WorldWideScience

Sample records for preheat ventilation air

  1. Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2015-01-01

    Full Text Available This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h and catalytic oxidation bed average temperature (20°C to 560°C within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry.

  2. Ventilated Double Window for the Preheating of the Ventilation Air Comparison of Its Performance in a Northern and a Southern European Climate

    Directory of Open Access Journals (Sweden)

    Jorge S. Carlos

    2013-01-01

    Full Text Available Keeping the indoor air quality within the reference levels requires that the polluted indoor air be replaced by fresh air coming from the outside. This paper presents a sensitivity analysis and a series of simulations where the performance of this passive system is studied. The influence of each relevant factor, like the wind, the solar radiation, and the outdoor air temperature, is assessed. Two different local sets of climatic data were chosen, a mild and a cold winter.

  3. A comparison of winter pre-heating requirements for natural displacement and natural mixing ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Andrew W. [BP Institute, University of Cambridge, Cambridge, CB3 OEZ (United Kingdom); Fitzgerald, Shaun; Livermore, Stephen [E-Stack Ltd., St Johns Innovation Centre, Cambridge (United Kingdom)

    2009-12-15

    In winter, natural ventilation can be achieved either through mixing ventilation or upward displacement ventilation (P.F. Linden, The fluid mechanics of natural ventilation, Annual Review of Fluid Mechanics 31 (1999) pp. 201-238). We show there is a significant energy saving possible by using mixing ventilation, in the case that the internal heat gains are significant, and illustrate these savings using an idealized model, which predicts that with internal heat gains of order 0.1 kW per person, mixing ventilation uses of a fraction of order 0.2-0.4 of the heat load of displacement ventilation assuming a well-insulated building. We then describe a strategy for such mixing natural ventilation in an atrium style building in which the rooms surrounding the atrium are able to vent directly to the exterior and also through the atrium to the exterior. The results are motivated by the desire to reduce the energy burden in large public buildings such as hospitals, schools or office buildings centred on atria. We illustrate a strategy for the natural mixing ventilation in order that the rooms surrounding the atrium receive both pre-heated but also sufficiently fresh air, while the central atrium zone remains warm. We test the principles with some laboratory experiments in which a model air chamber is ventilated using both mixing and displacement ventilation, and compare the energy loads in each case. We conclude with a discussion of the potential applications of the approach within the context of open plan atria type office buildings. (author)

  4. Improved design and operation of crude furnace air preheater for cold climates

    Energy Technology Data Exchange (ETDEWEB)

    Gollpudi, B. [Bantrel Co. (Canada); Nichols, D. [Husky Energy (Canada)

    2011-07-01

    In the heavy oil industry, air preheaters are used to heat combustion air with hot flue gas. Flue gas contains significant amounts of sulphur oxides which can result in acid dew point corrosion on the flue gas side. The air preheater metal has therefore to be kept at a temperature higher than this dew point to provide trouble free operation. This paper relates a case of dew point corrosion damage in an air preheater and the design modifications made to solve the problem. The case studied took place at the crude furnace at Husky Energy's Lloydminster Upgrader where a plate exchanger air preheater was installed in 2007 and corrosion was noticed in 2009. It was found that hot air recirculation helps in maintaining a sufficiently high temperature and that the ducting design avoids dead zones. This paper showed that improved design can help to prevent damage occurring in the air preheater.

  5. Prediction and mitigation of air preheater fouling due to ammonium bisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, R.; Tavoulareas, S.; Stallings, J. [Energy and Environmental Strategies, MA (United States)

    2001-07-01

    This paper provides a brief review of the fundamentals of ammonium bisulfate (ABS) formation, deposition and fouling in the air preheater. It presents a software-based predictive model for assessing the potential for air preheater fouling as a result of proposed SNCR or SCR retrofits and considering site-specific conditions and introduces a software-based cost-benefit model for assessing the economic trade-offs of various ABS fouling mitigation options. 7 refs., 13 figs.

  6. Adaptive preheating duration control for low-power ambient air quality sensor networks.

    Science.gov (United States)

    Baek, Yoonchul; Atiq, Mahin K; Kim, Hyung Seok

    2014-03-20

    Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback-large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC) method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  7. Adaptive Preheating Duration Control for Low-Power Ambient Air Quality Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yoonchul Baek

    2014-03-01

    Full Text Available Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback—large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  8. Corrosion on air preheaters and economisers; Korrosion hos luftfoervaermare och ekonomisrar

    Energy Technology Data Exchange (ETDEWEB)

    Nordling, Magnus

    2012-05-15

    Combustion plants in Sweden are exposed to considerable stress regarding low temperature corrosion, and failures due to low temperature corrosion occur regularly. Particularly common is corrosion problems connected to air preheaters and economisers. The number of combustion plants having air preheaters and economisers is however large, and the result of a collection of experiences regarding corrosion on air preheaters and economisers therefore has the potential to give a broad knowledge base. The summary of collection of experiences that has been done here, complemented with a literature survey, is expected to give plant owners and plant constructors a valuable tool to prevent corrosion on the flue gas side of air preheaters and economisers. The choice of plants for the inquiry was made using a list from the Swedish Naturvaardsverket (Environmental Protection Agency) indicating the emissions of NO{sub x}gases from Swedish combustion plants. From that list mainly the plants with the largest emissions were chosen, resulting in a number of 30 plants. Depending on that most of the plants have several boilers, and that the connected tubes often have several economisers and air preheaters, the number of economisers and air preheaters in this experience collection is at least 85. The study was however not limited to economisers and air preheaters, but also experiences connected to corrosion of other units were collected when mentioned, and the most interesting information here is also included in the report. Also a number of the plants were visited to improve the basis of the report, e.g. by photographing the most interesting parts. As the insight of the extension of the problem increased, renewed interview rounds were made, and the last one was made in August 2011.

  9. Transpired Solar Collector at NREL's Waste Handling Facility Uses Solar Energy to Heat Ventilation Air (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2010-09-01

    The transpired solar collector was installed on NREL's Waste handling Facility (WHF) in 1990 to preheat ventilation air. The electrically heated WHF was an ideal candidate for the this technology - requiring a ventilation rate of 3,000 cubic feet per meter to maintain safe indoor conditions.

  10. The benefit of solid oxide fuel cells with integrated air pre-heater

    Energy Technology Data Exchange (ETDEWEB)

    Costamagna, P. [Univ. degli Studi di Genova, Fac. di Ingegneria, ISTIC, Inst. di Ingegneria Chimica e di Processo `G.B. Bonino`, Genova (Italy)

    1997-11-01

    A new design has recently been proposed in the field of solid oxide fuel cells, consisting of a traditional electrochemical cell integrated with a pre-heater. In this paper a simulation model for the rectangular planar solid oxide fuel cell with integrated air pre-heater is presented. A two-dimensional stack simulation is presented as well, one axis coincides with the fuel flow direction, the other with the stack height. Local quantities such as current density, gas and solid temperatures are reported and cell characteristics predicted. In a parameter study, effects of oxygen utilisation and heat-transfer conditions in the pre-heater on the local temperature distribution of the solid structure are considered. As a result, the benefit of the new cell design becomes evident when low air flow rates are applied. A further advantage associated with the reduced flow rate is the low air temperature at the inlet. (orig.)

  11. Equivalence in Ventilation and Indoor Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  12. Electronically Controlling the System of Preheating Intake Air by Flame for Diesel Engine Cold-Start

    Institute of Scientific and Technical Information of China (English)

    杜巍; 赵福堂

    2003-01-01

    In order to improve the cold-start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self-ignite at the end of compression process at different temperatures of coolant and intake-air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro-controller unit (MCS-8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.

  13. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater

    Energy Technology Data Exchange (ETDEWEB)

    J. Menasha; D. Dunn-Rankin; L. Muzio; J. Stallings [University of California Irvine, Irvine, CA (United States). Department of Mechanical and Aerospace Engineering

    2011-07-15

    Ammonium bisulfate (ABS) forms in coal-fired power plant exhaust systems when ammonia slip from the NOx control system reacts with the sulfur oxides and water in the flue gas. The critical temperature range for ABS formation occurs in the air preheater, where ABS is known to cause corrosion and pluggage that can require unplanned outages and expensive cleaning. To develop mitigation strategies for the deleterious effects of ABS in air preheaters, it is important to know its formation temperature and deposition process. This paper describes a bench-scale experimental simulation of a single-channel air preheater, with the appropriate temperature gradient, used in conjunction with simulated coal combustion flue gas, including sulfur oxides, ammonia, and water vapor, to investigate the formation of ABS. Formation was observed optically, and the formation temperature, as well as deposition characteristics for a realistic range of reactant concentrations are presented and compared with previous studies on ABS formation. This study presents data at realistic concentrations not earlier tested, and the reported data has smaller experimental uncertainty than previously obtained. We found that the measured ABS formation temperatures under air preheater channel conditions lies between the temperatures reported by others, and is in the range of 500-520 K for typical flue gas concentrations of ammonia and sulfur oxide species. The results also show that, at least for this experimental configuration, ABS forms predominantly as an aerosol in the gas phase rather than as a condensate on the channel walls. 13 refs., 13 figs., 2 tabs.

  14. System Performance Measurement Supports Design Recommendations for Solar Ventilation Preheat System (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-08-01

    Technical briefing to report the outcomes of a data monitoring effort to determine the nature of solar vent preheat system performance problems at a U.S. military installation. The analysis reports up-to-date research and findings regarding system design, helping to clarify the issue as a factor of system design, rather than a shortcoming of SVP systems.

  15. Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fired Heat Treatment Furnace

    Directory of Open Access Journals (Sweden)

    E B Muhammed Shafi,

    2015-09-01

    Full Text Available This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating. The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC is obtained. The test was caaried out at Peekay Steels Casting (P ltd, Nallalam, Calicut.

  16. 空气预热器的改造%Revamping of air preheater

    Institute of Scientific and Technical Information of China (English)

    廖艳玲

    2011-01-01

    The revamping of air preheater in the waste heat recovery system of a 4.1 MM TPY diesel hy-drotreating unit in SINOPEC Qingdao Refining & Chemical Co. , Ltd. Was introduced. An analysis was performed on how to revamp the air preheater to reduce flue gas emission temperature of waste heat recovery system so as to improve the thermal efficiency of fired heaters. After revamping, the flue gas emission temperature is about 30 ℃ lower than that before the revamping, the thermal energy obtained by the air is much higher than that before replacement of pre-heater tubes and energy saving is significant.%介绍了中国石化青岛炼油化工有限责任公司余热回收系统的空气预热器的改造情况,分析了如何通过对空气预热器的改造来降低余热回收系统排烟温度,从而提高加热炉的热效率.改造后,烟气排烟温度比改造前降低30℃左右,空气所获得的能量比更换热管前有较大提高,节能效果显著.

  17. Short-term airing by natural ventilation

    DEFF Research Database (Denmark)

    Perino, Marco; Heiselberg, Per

    2009-01-01

    traditional mechanical ventilation components with natural ventilation devices, such as motorized windows and louvers. Among the various ventilation strategies that are currently available, buoyancy driven single-sided natural ventilation has proved to be very effective and can provide high air change rates...... that was aimed at developing and validating numerical models for the analysis of buoyancy driven single-sided natural ventilation systems. Once validated, these models can be used to optimize control strategies in order to achieve satisfactory indoor comfort conditions and IAQ....

  18. Hybrid Ventilation Air Flow Process

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols

    The scope of this annex is therefore to obtain better knowledge of the use of hybrid ventilation technologies. The annex focus on development of control strategies for hybrid ventilation, on development of methods to predict hybrid ventilation performance in office buildings and on implementation...

  19. Combustion Air Pre-heating from Ash Sensible Heat in Municipal Waste Incineration Systems

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    Zakariya Kaneesamkandi

    2014-01-01

    Full Text Available Heat recovery from bottom ash is more important in municipal waste combustion systems than in any other solid fuel combustion since almost 50% of it comprises of non-combustibles. In this study, an ash cooling system using air as the cooling medium has been modeled for pre-heating the combustion air. Air cooling has several advantages over water cooling methods. The study involves modeling using Gambit tool and is solved with the fluent solver. Municipal solid waste incineration systems have the advantage of being located near the waste collection area apart from the high volume reduction ratio. Improvements in the emission control systems and combustion technology can make incineration a highly feasible disposal method. Low furnace temperature due to heat losses through fuel moisture loss and ash sensible heat loss has been a disadvantage with these systems. In this study, a small percentage of the combustion air is pre-heated in a non-contact type heat exchanger and its effect on the available energy of combustion gases at the evaporator outlet is studied. The study is performed for two different waste samples. Results indicate significant increase in available energy at the evaporator outlet and better relative performance for the lower grade fuel. A comparison is made with similar methods reported in the literature along with a brief discussion on the methodologies adopted. The results confirm the importance of installing ash sensible heat recovery mechanism for waste incineration systems as well as the feasibility of the air based method.

  20. Air Distribution in a Furnished Room Ventilated by Mixing Ventilation

    DEFF Research Database (Denmark)

    Nielsen, June Richter; Nielsen, Peter V.; Svidt, Kjeld

    Using isothermal full-scale experiments and two-dimensional isothermal CFD simulations it is investigated how normal office furniture influences the air movements in a room with mixing ventilation. Three different set-ups are made in the experiments and different sizes and locations of the furnit......Using isothermal full-scale experiments and two-dimensional isothermal CFD simulations it is investigated how normal office furniture influences the air movements in a room with mixing ventilation. Three different set-ups are made in the experiments and different sizes and locations...

  1. VENTILATION INFLUENCE UPON INDOOR AIR RADON LEVEL

    Institute of Scientific and Technical Information of China (English)

    田德源

    1995-01-01

    Levels of indoor radon in air are studied by a continuous electrostatic radon monitor under normal living conditions to evaluate the influence of air conditioned ventilation on indoor air radon level.Results show that the indoor air radon concentrations are not much more than those without household conditioner living condition.although using household conditioner requires a sealed room which should lead to a higher radon level.Turning on air conditioner helps lower indoor radon level.Therefore.the total indoor air Rn levels are normal>ventilation>exhaust or indraft> exhaust plus indraft.

  2. Gasifier selection, design and gasification of oil palm fronds with preheated and unheated gasifying air.

    Science.gov (United States)

    Guangul, Fiseha M; Sulaiman, Shaharin A; Ramli, Anita

    2012-12-01

    Oil palm frond biomass is abundantly available in Malaysia, but underutilized. In this study, gasifiers were evaluated based on the available literature data and downdraft gasifiers were found to be the best option for the study of oil palm fronds gasification. A downdraft gasifier was constructed with a novel height adjustment mechanism for changing the position of gasifying air and steam inlet. The oil palm fronds gasification results showed that preheating the gasifying air improved the volumetric percentage of H(2) from 8.47% to 10.53%, CO from 22.87% to 24.94%, CH(4) from 2.02% to 2.03%, and higher heating value from 4.66 to 5.31 MJ/Nm(3) of the syngas. In general, the results of the current study demonstrated that oil palm fronds can be used as an alternative energy source in the energy diversification plan of Malaysia through gasification, along with, the resulting syngas quality can be improved by preheating the gasifying air.

  3. Waste Heat Recovery by Heat Pipe Air-Preheater to Energy Thrift from the Furnace in a Hot Forging Process

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

    Full Text Available Problem statement: Currently, the heat pipe air-preheater has become importance equipment for energy recovery from industrial waste heat because of its low investment cost and high thermal conductivity. Approach: This purpose of the study was to design, construct and test the waste heat recovery by heat pipe air-preheater from the furnace in a hot brass forging process. The mathematical model was developed to predict heat transfer rate and applied to compute the heat pipe air-preheater in a hot brass forging process. The heat pipe air-preheater was designed, constructed and tested under medium temperature operating conditions with inlet hot gas ranging between 370-420°C using water as the working fluid with 50% filling by volume of evaporator length. Results: The experiment findings indicated that when the hot gas temperature increased, the heat transfer rate also increased. If the internal diameter increased, the heat transfer rate increased and when the tube arrangement changed from inline to staggered arrangement, the heat transfer rate increased. Conclusion/Recommendations: The heat pipe air-preheater can reduced the quantity of using gas in the furnace and achieve energy thrift effectively.

  4. Heating, ventilation and air conditioning system modelling

    Energy Technology Data Exchange (ETDEWEB)

    Whalley, R.; Abdul-Ameer, A. [British University in Dubai (United Arab Emirates)

    2011-03-15

    Heating, ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. Existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of distributed-lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system element characteristics, is advocated. A dynamic model for a heating, ventilation and air conditioning system comprising inlet and exhaust fans, with air recirculation, heating/cooling and filtration units is presented. Pressure, airflow and temperature predictions within the system are computed following input, disturbance changes and purging operations. The generalised modelling advancements adopted and the applicability of the model for heating, ventilation and air conditioning system simulation, re-configuration and diagnostics is emphasised. The employment of the model for automatic, multivariable controller design purposes is commented upon. (author)

  5. Short Term Airing by Natural Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Perino, M.

    2010-01-01

    principles is necessary. The present study analyses and presents the results of an experimental evaluation of airing performance in terms of ventilation characteristics, IAQ and thermal comfort. It includes investigations of the consequences of opening time, opening frequency, opening area and expected...... airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective...... and can provide both acceptable IAQ and thermal comfort conditions in buildings....

  6. [Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

    Science.gov (United States)

    Bellucci Sessa, R; Riccio, G

    2004-01-01

    After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

  7. Perceived Air Quality in a Displacement Ventilated Room

    DEFF Research Database (Denmark)

    Brohus, Henrik; Knudsen, Henrik Nellemose; Nielsen, Peter V.

    In a displacement ventilated room the non-uniform contaminant distribution causes an improved indoor air quality in the occupied zone compared with conventional mixing ventilation. This has been demonstrated in numerous studies by chemical measurements. In this study the air quality...... in a displacement ventilated room was determined directly by asking humans about how they perceived the air quality. A trained sensory panel comprising 12 subjects assessed the perceived air quality immediately after entering a climate chamber. The experiments showed that the perceived air quality...... in the displacement ventilated chamber was substantially better than in the case of mixing ventilation....

  8. FAILURE ANALYSIS IN TUBING OF AIR PREHEATER OF BOILER FROM A SUGARCANE MILL

    Directory of Open Access Journals (Sweden)

    Joner Oliveira Alves

    2014-10-01

    Full Text Available The increased demand for energy from sugarcane bagasse has made the sugar and alcohol mills search alternatives to reduce maintenance of the boilers, releasing more time to the production. The stainless steel use has become one of the main tools for such reduction. However, specification errors can lead to premature failures. This work reports the factors that led tubes of AISI 409 stainless steel fail after half season when applied in a air preheater of boiler from a sugarcane mill. In such application, the AISI 304 lasts about 15 seasons and the carbon steel about 3. A tube sent by the sugar mill was characterized by wet chemical analysis, optical microscopy and EDS. Results indicated chloride formation on the internal walls of the tube, which combined with the environment, accelerated the corrosion process. The carbon steel showed high lifetime due to a 70% higher thickness. Due to the work condictions is recommended the use of stainless steels with higher corrosion resistance, such as the traditional AISI 304 or the ferritic AISI 444, the last presents better thermal exchange.

  9. Design of a DCS Based Model for Continuous Leakage Monitoring System of Rotary Air Preheater of a Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    Madan BHOWMICK

    2011-01-01

    Full Text Available The leakage in rotary air preheater makes a considerable contribution to the reduced overall efficiency of fossil-fuel-fired thermal power plants and increase the effect on environment. Since it is normal phenomenon, continuous monitoring of leakage is generally omitted in most power plants. But for accurate analysis of the operation of the thermal power plant, this leakage monitoring plays a vital role. In the present paper, design of a DCS based model for continuous leakages monitoring of rotary air preheater has been described. In the proposed model, the existing DCS based instrumentation system has been modified and online leakage monitoring system has been developed. This model has been installed in a captive power plant with high capacity boilers and very much satisfactory operation of this system has been observed. The observed online data along with their analysis results are presented in this paper.

  10. Demonstration of the Performance of an Air-Type Photovoltaic Thermal (PVT System Coupled with a Heat-Recovery Ventilator

    Directory of Open Access Journals (Sweden)

    Jin-Hee Kim

    2016-09-01

    Full Text Available A heat-recovery ventilator (HRV effectively conducts ventilation by recovering waste heat from indoors to outdoors during heating periods. However, dew condensation associated with the HRV system may arise due to the difference between the indoor temperature and the very low outdoor temperature in winter, and this can decrease the heat exchange efficiency. These problems can be solved by the pre-heating of the incoming air, but additional energy is required when pursuing such a strategy. On the other hand, an air-type photovoltaic thermal (PVT system produces electricity and thermal energy simultaneously using air as the heat transfer medium. Moreover, the heated air from the air-type PVT system can be connected to the HRV to pre-heat the supply air instead of taking in the cold outdoor air. Thus, the ventilation efficiency can be improved and the problems arising during the heating period can be resolved. Consequentially, the heating energy required in a building can be reduced, with additional electricity acquired as well. In this paper, the performance of an air-type PVT system coupled with an HRV is assessed. To do this, air-type PVT collectors operating at 1 kWp were installed in an experimental house and coupled to an HRV system. Thermal performance and heating energy required during the winter season were analyzed experimentally. Furthermore, the electrical performances of the air-type PVT system with and without ventilation at the back side of the PV during the summer season were analyzed.

  11. Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

    Science.gov (United States)

    The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

  12. Experimental evaluation of air distribution in mechanically ventilated residential rooms

    DEFF Research Database (Denmark)

    Tomasi, R.; Krajčík, M.; Simone, A.

    2013-01-01

    The effect of low ventilation rates (1 or 0.5 air change per hour) on thermal comfort and ventilation effectiveness was experimentally studied in a simulated residential room equipped with radiant floor heating/cooling and mixing ventilation systems. The tests were performed for various positions...... removal effectiveness (CRE) and local air change index was measured in order to characterize ventilation effectiveness in the occupied zone. Acceptable thermal comfort was found in most experiments; however, air temperature differences higher than 3 °C occurred when floor cooling was combined...... with unconditioned outdoor air supply, i.e. at the supply air temperatures higher than the room air temperature. Moreover, low floor temperatures were needed to maintain the desired reference temperature in the stratified thermal environment. Mainly in cooling conditions the ventilation effectiveness depended...

  13. Experimental Analysis and Model Validation of an Opaque Ventilated Facade

    DEFF Research Database (Denmark)

    López, F. Peci; Jensen, Rasmus Lund; Heiselberg, Per

    2012-01-01

    Natural ventilation is a convenient way of reducing energy consumption in buildings. In this study an experimental module of an opaque ventilated façade (OVF) was built and tested for assessing its potential of supplying free ventilation and air preheating for the building. A numerical model was ...

  14. Energy Efficiency for Heating, Ventilating, Air-Conditioning Instructors.

    Science.gov (United States)

    Scharmann, Larry, Ed.; Lay, Gary, Ed.

    Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains five units on energy efficiency that were designed to be incorporated into an existing program in heating, ventilating, and air-conditioning. The following topics are examined: how energy conservation pays, heating, ventilation, air-conditioning,…

  15. Energy Efficiency for Heating, Ventilating, Air-Conditioning Instructors.

    Science.gov (United States)

    Scharmann, Larry, Ed.; Lay, Gary, Ed.

    Intended primarily but not solely for use at the postsecondary level, this curriculum guide contains five units on energy efficiency that were designed to be incorporated into an existing program in heating, ventilating, and air-conditioning. The following topics are examined: how energy conservation pays, heating, ventilation, air-conditioning,…

  16. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air systems...

  17. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.; Bergey, D.

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  18. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Somerville, MA (United States); Bergey, Daniel [Building Science Corporation, Somerville, MA (United States)

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  19. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    Science.gov (United States)

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry ( 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  20. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate... holding of a drug product. (c) Air filtration systems, including prefilters and particulate matter...

  1. New Air Cleaning Strategies for Reduced Commercial Building Ventilation Energy

    Energy Technology Data Exchange (ETDEWEB)

    Sidheswaran, Meera; Destaillats, Hugo; Sullivan, Douglas P.; Fisk, William J.

    2010-10-27

    Approximately ten percent of the energy consumed in U.S. commercial buildings is used by HVAC systems to condition outdoor ventilation air. Reducing ventilation rates would be a simple and broadly-applicable energy retrofit option, if practical counter measures were available that maintained acceptable concentrations of indoor-generated air pollutants. The two general categories of countermeasures are: 1) indoor pollutant source control, and 2) air cleaning. Although pollutant source control should be used to the degree possible, source control is complicated by the large number and changing nature of indoor pollutant sources. Particle air cleaning is already routinely applied in commercial buildings. Previous calculations indicate that particle filtration consumes only 10percent to 25percent of the energy that would otherwise be required to achieve an equivalent amount of particle removal with ventilation. If cost-effective air cleaning technologies for volatile organic compounds (VOCs) were also available, outdoor air ventilation rates could be reduced substantially and broadly in the commercial building stock to save energy. The research carried out in this project focuses on developing novel VOC air cleaning technologies needed to enable energy-saving reductions in ventilation rates. The minimum required VOC removal efficiency to counteract a 50percent reduction in ventilation rate for air cleaning systems installed in the HVAC supply airstream is modest (generally 20percent or less).

  2. Air distribution and ventilation effectiveness in an occupied room heated by warm air

    DEFF Research Database (Denmark)

    Krajcik, Michal; Simone, Angela; Olesen, Bjarne W.

    2012-01-01

    and at different simulated outside conditions, internal heat gains and air change rates. Floor heating was also simulated and compared with the warm air heating system. Vertical air temperature profiles, air velocity profiles and equivalent temperatures were derived in order to describe the thermal environment......Air distribution, ventilation effectiveness and thermal environment were experimentally studied in a simulated room in a low-energy building heated and ventilated by warm air supplied by a mixing ventilation system. Measurements were performed for various positions of the air terminal devices....... Contaminant removal effectiveness and air change efficiency were used to evaluate ventilation effectiveness. No significant risk of thermal discomfort due to vertical air temperature differences or draught was found. When the room was heated by warm air, buoyancy forces were important for ventilation...

  3. Mixing Ventilation. Guide on mixing air distribution design

    DEFF Research Database (Denmark)

    Kandzia, Claudia; Kosonen, Risto; Melikov, Arsen Krikor

    In this guidebook most of the known and used in practice methods for achieving mixing air distribution are discussed. Mixing ventilation has been applied to many different spaces providing fresh air and thermal comfort to the occupants. Today, a design engineer can choose from large selection...... of air diffusers and exhaust openings....

  4. Mixing ventilation guide on mixing air distribution design

    CERN Document Server

    Kandzia, Claudia; Kosonen, Risto; Krikor Melikov, Arsen; Nielsen, Peter Vilhelm

    2013-01-01

    In this guidebook most of the known and used in practice methods for achieving mixing air distribution are discussed. Mixing ventilation has been applied to many different spaces providing fresh air and thermal comfort to the occupants. Today, a design engineer can choose from large selection of air diffusers and exhaust openings.

  5. Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met. ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM2.5, formaldehyde and NO2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.

  6. The influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation.

    Directory of Open Access Journals (Sweden)

    Jícha M.

    2013-04-01

    Full Text Available The paper deals with instigation of influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation. CFD approach was used for investigation and model geometry was based on small aircraft cabin mock-up geometry. Model was also equipped by nine seats and five manikins that represent passengers. The air jet direction was observed for selected ambient environment parameters and several types of air duct geometry and influence of main air duct geometry on jets direction is discussed. The model was created in StarCCM+ ver. 6.04.014 software and polyhedral mesh was used.

  7. The influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation.

    Science.gov (United States)

    Fišer, J.; Jícha, M.

    2013-04-01

    The paper deals with instigation of influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation. CFD approach was used for investigation and model geometry was based on small aircraft cabin mock-up geometry. Model was also equipped by nine seats and five manikins that represent passengers. The air jet direction was observed for selected ambient environment parameters and several types of air duct geometry and influence of main air duct geometry on jets direction is discussed. The model was created in StarCCM+ ver. 6.04.014 software and polyhedral mesh was used.

  8. Experimental Investigation on Local Air Age and Air Distribution of Stratum Ventilation

    Institute of Scientific and Technical Information of China (English)

    WANG Feng-hao; LI Yuan-bin; LIU Xiao-dong; WANG Xin-ke

    2009-01-01

    Because of the multiple problems on high energy consumption and unbalanced thermal comfort caused by the traditional ventilation system,a new concept of ventilation-stratum ventilation has been proposed,which sends the fresh air to the breathing zone directly.In this paper,the local air distributions of the displace-ment ventilation and the stratum ventilation in a model office were measured.The air ages in the breathing zone for the displacement ventilation and stratum ventilation were compared with the tracer gas concentration decay method.The decay curves of tracer gas concentration for these two ventilation systems in the breathing zonewere obtained, and the air ages were calculated.The experimental results show that the stratum ventilation sys-tem can offer lower air age for four mechanically ventilated cases in the breathing zone,and it can also provide better thermal comfort,which renews the air of breathing zone more quickly and reduces the energy consump-tion in some degree.The experimental investigation provides a theoretical basis for the application of stratum ventilation system.

  9. Measurements and prediction of inhaled air quality with personalized ventilation

    DEFF Research Database (Denmark)

    Cermak, Radim; Majer, M.; Melikov, Arsen Krikor

    2002-01-01

    This paper examines the performance of five different air terminal devices for personalized ventilation in relation to the quality of air inhaled by a breathing thermal manikin in a climate chamber. The personalized air was supplied either isothermally or non-isothermally (6 deg.C cooler than...... the room air) at flow rates ranging from less than 5 L/s up to 23 L/s. The air quality assessment was based on temperature measurements of the inhaled air and on the portion of the personalized air inhaled. The percentage of dissatisfied with the air quality was predicted. The results suggest...

  10. Capture and Use of Coal Mine Ventilation Air Methane

    Energy Technology Data Exchange (ETDEWEB)

    Deborah Kosmack

    2008-10-31

    CONSOL Energy Inc., in conjunction with MEGTEC Systems, Inc., and the U.S. Department of Energy with the U.S. Environmental Protection Agency, designed, built, and operated a commercial-size thermal flow reversal reactor (TFRR) to evaluate its suitability to oxidize coal mine ventilation air methane (VAM). Coal mining, and particularly coal mine ventilation air, is a major source of anthropogenic methane emissions, a greenhouse gas. Ventilation air volumes are large and the concentration of methane in the ventilation air is low; thus making it difficult to use or abate these emissions. This test program was conducted with simulated coal mine VAM in advance of deploying the technology on active coal mine ventilation fans. The demonstration project team installed and operated a 30,000 cfm MEGTEC VOCSIDIZER oxidation system on an inactive coal mine in West Liberty, WV. The performance of the unit was monitored and evaluated during months of unmanned operation at mostly constant conditions. The operating and maintenance history and how it impacts the implementation of the technology on mine fans were investigated. Emission tests showed very low levels of all criteria pollutants at the stack. Parametric studies showed that the equipment can successfully operate at the design specification limits. The results verified the ability of the TFRR to oxidize {ge}95% of the low and variable concentration of methane in the ventilation air. This technology provides new opportunities to reduce greenhouse gas emissions by the reduction of methane emissions from coal mine ventilation air. A large commercial-size installation (180,000 cfm) on a single typical mine ventilation bleeder fan would reduce methane emissions by 11,000 to 22,100 short tons per year (the equivalent of 183,000 to 366,000 metric tonnes carbon dioxide).

  11. MARANGONI CONVECTION AROUND A VENTILATED AIR BUBBLE UNDER MICROGRAVITY CONDITIONS

    NARCIS (Netherlands)

    HOEFSLOOT, HCJ; JANSSEN, LPBM; HOOGSTRATEN, HW

    Under microgravity conditions in both parabolic and sounding rocket flights, the mass-transfer-induced Marangoni convection around an air bubble was studied. To prevent the bubble from becoming saturated, the bubble was ventilated. It turned out that the flow rate of the air through the bubble

  12. Air Distribution and Ventilation Effectiveness in a room with Floor/Ceiling Heating and Mixing/Displacement Ventilation

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.

    2014-01-01

    The present study investigated different combinations of floor/ceiling heating with mixing/displacement ventilation and their impacts on the indoor air distribution and ventilation effectiveness. Measurements were performed in a room during heating season in December. The results show that indoor...... combined with floor/ceiling heating systems is approximately equal to 1.0, and ventilation effectiveness of displacement ventilation system combined with floor/ceiling heating systems ranges from 1.0 to 1.2. The floor/ceiling heating systems combined with mixing ventilation system have more uniform indoor...... air distribution but smaller ventilation effectiveness compared with the floor/ceiling heating systems combined with displacement ventilation system. With regard to the building heat loss increased by non-uniform indoor air distribution and small ventilation effectiveness, there should be an optimal...

  13. INTEGRATED PURIFICATION OF VENTILATED AIR IN AIR LAYERS OF DAMP BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    V. V. Shitov

    2011-04-01

    Full Text Available Problem statement. Intensive wear of the structure bearing elements in premises with high moisture content in ventilated air is associated with cyclic changes in temperature and humidity indicators of steam-air environment; hence, the problem of ventilated air treatment in such premises is topical.Results. The design of device for integrated purification of atmospheric ventilated air from fine-dispersed pollutants in premise with high moisture content in indoor air is developed.Conclusions. The proposed device provides reliable and long-term operation of bearing building elements.

  14. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat…

  15. Cast iron air preheater and commercial application%铸铁式空气预热器及工业应用

    Institute of Scientific and Technical Information of China (English)

    王德瑞

    2012-01-01

    As cast iron has a high corrosion resistance performance, the air preheater fabricated from cast iron material is resistant to corrosion and extended in service life. It is especially applicable for the low-temperature section of waste heat recovery system for industry furnace flue gas. The past and present applications of cast iron air preheaters in boiler, iron & steel production and petrochemical industries are described in detail , and the new development of large cast iron plate air preheater developed by SINOPEC in recent years is presented. Up to now, the large cast iron plate air preheaters have been selected in the design of a large number of fired heaters and its design, fabrication and installation technologies are becoming commercially proven. In April, 2010, China' s first new type cast iron plate air preheater came on stream in No. 2 atmospheric-vacuum distillation unit in No. 2 atmospheric-vacuum distillation unit in SINOPEC Wuhan Petrochemical Company. In 19 months' operation, the heat efficiency of the furnace has been maintained at over 92% and the temperature of flue gas emission was lower than 130 t. The preheater has been operating smoothly ever since.%铸铁具有很强的耐硫酸腐蚀能力,因此,采用铸铁材料制作的空气预热器具有耐腐蚀、长寿命的特点,特别适合在工业炉烟气余热回收系统中的低温段采用.介绍了铸铁式空气预热器在国内锅炉、钢铁和石化行业过去和现在的工业应用情况,以及中国石化近年开发的大型铸铁板式空气预热器的最新进展.目前,国产大型铸铁板式空气预热器已在多台火焰加热炉的设计中采用,设计、制造、安装技术日臻成熟.2010年4月,武汉石化2号常减压蒸馏装置投用了国产第一台新型铸铁板式空气预热器,运行19个月,加热炉热效率一直稳定在92%以上,排烟温度一直稳定在130℃以下,运行良好.

  16. Prediction of Perceived Air Quality for Personalized Ventilation Systems

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingfan; ZHAO Rongyi

    2005-01-01

    The characteristics of the air jet from the outlet of a personalized ventilation system were related to the perceived air quality and ventilation rate. The perceived air quality was expressed as percentage of dissatisfied people for a system supplying isothermal fresh air. The relationship was verified using a thermal manikin with a breathing function in a climate chamber sitting by a desk equipped with a personalized ventilation system. A trace gas was introduced into the climate chamber and fully mixed. The personal exposure effectiveness (εp) is based on concentrations of trace gas in the chamber and in the manikin nose which is affected more by the distance between the movable outlet and the occupant's breathing zone than by the personalized air flowrate and does not change much for the personalized air flowrate higher than 10 L/s when the distance is fixed. Some predicted dissatisfied values for a personalized ventilation system compared with those acquired in human subject experiments have an absolute difference of less than 3%.

  17. Experimental study of air distribution and ventilation effectiveness in a room heated by warm air and/or floor heating

    DEFF Research Database (Denmark)

    Simone, Angela; Olesen, Bjarne W.; Krajčík, Michal

    2010-01-01

    The levels of required ventilation depend on the criteria for indoor air quality in existing standards and guidelines. On top of that, the resulting ventilation in air changes per hour is depending on the ventilation effectiveness. In the standard CR 1752 the recommended values for ventilation...

  18. Displacement and air distribution ventilation systems; Verdringingsventilatie- en luchtverdeelsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Van Holten, P. [Solid Air, Amsterdam (Netherlands)

    2009-06-15

    Since an evaporative cooling system uses 100% clean outdoor air; it is ideal for positive displacement ventilation. By using the overpressure inside the building or room, windows and doors can be opened without affecting the controlled room temperature. The combination of positive displacement ventilation/balance ventilation with heat recovery is a very attractive solution. In this article you will find a brief explanation of the operation, application and basic principles of positive displacement ventilation. [Dutch] Verdampingskoeling leent zich in het bijzonder voor verdringingsventilatie dankzij het gebruik van 100% buitenlucht. Gebruikmakend van overdruk kunnen daarbij ramen en deuren worden geopend zonder dat de temperatuur hierdoor sterk wordt beinvloed. De combinatie verdringingsventilatie/balansventilatie met WTW, zoals in De Vijfhoek, is daarbij een voor de hand liggende optie. In dit artikel worden de basisprincipes van verdringingsventilatie, alsmede de werking en toepassing hiervan, toegelicht.

  19. Are Ventilation Filters Degrading Indoor Air Quality in California Classrooms?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Destaillats, H.; Apte, M.G.; Destaillats,, Hugo; Fisk, Michael G. Apte and William J.

    2008-10-01

    Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects studenthealth and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air?conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone deposition in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent towhich filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.

  20. Indoor Air Quality and Ventilation in Residential Deep Energy Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan; Walker, Iain

    2014-06-01

    Because airtightening is a significant part of Deep Energy Retrofits (DERs), concerns about ventilation and Indoor Air Quality (IAQ) have emerged. To investigate this, ventilation and IAQ were assessed in 17 non-smoking California Deep Energy Retrofit homes. Inspections and surveys were used to assess household activities and ventilation systems. Pollutant sampling performed in 12 homes included six-day passive samples of nitrogen dioxide (NO2), formaldehyde and air exchange rate (AER); time-resolved data loggers were used to measure particle counts. Half of the homes provided continuous mechanical ventilation. Despite these homes being twice as airtight (3.0 and 7.6 ACH50, respectively), their median AER was indistinguishable from naturally vented homes (0.36 versus 0.37 hr--1). Numerous problems were found with ventilation systems; however, pollutant levels did not reach levels of concern in most homes. Ambient NO2 standards were exceeded in some gas cooking homes that used legacy ranges with standing pilots, and in Passive House-style homes without range hoods exhausted to outside. Cooking exhaust systems were installed and used inconsistently. The majority of homes reported using low-emitting materials, and formaldehyde levels were approximately half those in conventional new CA homes (19.7 versus 36 ?g/m3), with emissions rates nearly 40percent less (12.3 versus 20.6 ?g/m2/hr.). Presence of air filtration systems led to lower indoor particle number concentrations (PN>0.5: 8.80E+06 PN/m3 versus 2.99E+06; PN>2.5: 5.46E+0.5 PN/m3 versus 2.59E+05). The results indicate that DERs can provide adequate ventilation and IAQ, and that DERs should prioritize source control, particle filtration and well-designed local exhaust systems, while still providing adequate continuous ventilation.

  1. Design of energy efficient ventilation and air-conditioning systems

    CERN Document Server

    Seppänen, Olli; Bertilsson, Thore; Maripuu, Mari-Liis; Lamy, Hervé; Vanden Borre, Alex

    2012-01-01

    This guidebook covers numerous system components of ventilation and air-conditioning systems and shows how they can be improved by applying the latest technology products. Special attention is paid to details, which are often overlooked in the daily design practice, resulting in poor performance of high quality products once they are installed in the building system.

  2. State Skill Standards: Heating, Ventilation, Air Conditioning, and Refrigeration

    Science.gov (United States)

    Ball, Larry; Soukup, Dennis

    2006-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide career and technical education skill standards. The standards in this document are for Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) programs and are designed to clearly state what the student should know and be able to do upon completion of…

  3. Ductless personalized ventilation with local air cleaning

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Vesely, Michal; Melikov, Arsen Krikor

    2012-01-01

    was equipped with an activated carbon filter installed at the air intake, while the DPV at the second desk was without such a filter. The air temperature in the occupied zone (1.1 m above the floor) was 29 °C. The pollution load in the room was simulated by PVC floor covering. The subjects assessed...

  4. Ventilation as mitigation of PCB contaminated air in buildings

    DEFF Research Database (Denmark)

    Lyng, Nadja; Trap, Niels; Andersen, Helle Vibeke;

    2014-01-01

    The effect of ventilation on indoor concentrations was evaluated in 9 buildings constituting a total of 30 rooms. All cases had interior and/or exterior sealants containing PCB as primary source. Criteria for inclusion in the evaluation were that the indoor concentrations of PCBtotal In the remai......The effect of ventilation on indoor concentrations was evaluated in 9 buildings constituting a total of 30 rooms. All cases had interior and/or exterior sealants containing PCB as primary source. Criteria for inclusion in the evaluation were that the indoor concentrations of PCBtotal...... In the remaining four cases, the pressure difference between the room measured and the surroundings showed a tremendous effect on the concentration as opposed to the effect of ventilation. Pressure differences might affect the emission of PCB by motion of air through gaps and cracks along the PCB sealants. were...... measured in the same room at least twice and under different ventilation conditions. In general, PCB concentrations decrease with increased ventilation making the effect of ventilation to reduce human exposure feasible. In 26 case rooms, the mean reduction of the concentration was found to be 51% (median...

  5. Impacts of Ventilation Ratio and Vent Balance on Cooling Load and Air Flow of Naturally Ventilated Attics

    Directory of Open Access Journals (Sweden)

    Zhigang Shen

    2012-08-01

    Full Text Available The impacts of ventilation ratio and vent balance on cooling load and air flow of naturally ventilated attics are studied in this paper using an unsteady computational fluid dynamics (CFD model. Buoyancy-driven turbulent ventilations in attics of gable-roof residential buildings are simulated for typical summer conditions. Ventilation ratios from 1/400 to 1/25 combined with both balanced and unbalanced vent configurations are investigated. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the variations in ventilation ratio and vent configuration. The predicted temperature fields are characterized by thermal stratification, except for the soffit regions. It is demonstrated that an increase in ventilation ratio will reduce attic cooling load. Compared with unbalanced vent configurations, balanced attic ventilation is shown to be the optimal solution in both maximizing ventilating flow rate and minimizing cooling load for attics with ventilation ratio lower than 1/100. For attics with ventilation ratios greater than 1/67, a configuration of large ridge vent with small soffit vent favors ventilating air flow enhancement, while a configuration of small ridge vent with large soffit vent results in the lowest cooling energy consumption.

  6. An algorithm for calculating fresh air age in central ventilation system

    Institute of Scientific and Technical Information of China (English)

    LI; Xianting; (李先庭); Li; Dongning; (李冬宁); DOU; Chunpeng; (窦春鹏)

    2003-01-01

    Fresh air age is an important index to evaluate indoor environment. The conventional method for measuring or calculating fresh air age is only suitable for simple ventilation systems and not for central ventilation systems. In this paper, an algorithm for calculating fresh air age in central ventilation system is presented, which is based on the analysis of air flow in duct and air mixing. An example is given to illustrate the algorithm. The fresh air age in every ventilated room and duct can be acquired after all rooms and duct are directly calculated in turn without iteration. The algorithm is suitable for different central ventilation systems.

  7. Personalized ventilation: evaluation of different air terminal devices

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Cermak, Radim; Majer, M.

    2002-01-01

    was simulated in a climate chamber. A breathing thermal manikin was used to simulate a human being. Experiments at room air temperatures of 26 and 20 deg.C and personalized air temperatures of 20 deg.C supplied from the ATDs were performed. The flow rate of personalized air was changed from less than 5 up to 23...... of the personalized air with the polluted room air needs to be developed.......Personalized ventilation (PV) aims to provide clean air to the breathing zone of occupants. Its performance depends to a large extent on the supply air terminal device (ATD). Five different ATDs were developed, tested and compared. A typical office workplace consisting of a desk with mounted ATDs...

  8. Performance of personalized ventilation combined with chilled ceiling in an office room: inhaled air quality and contaminant distribution

    DEFF Research Database (Denmark)

    Lipczynska, Aleksandra; Kaczmarczyk, Jan; Melikov, Arsen Krikor

    2014-01-01

    In a simulated two persons’ office room inhaled air quality and contaminant distribution provided with personalized ventilation combined with chilled ceiling, mixing ventilation only, chilled ceiling with mixing ventilation and chilled ceiling with mixing and personalized ventilation was studied...

  9. Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

    Science.gov (United States)

    Katunská, Jana; Bullová, Iveta; Špaková, Miroslava

    2016-12-01

    The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

  10. Personalized ventilation: evaluation of different air terminal devices

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Cermak, Radim; Majer, M.

    2002-01-01

    of the body. An index, personal exposure effectiveness, was used to assess the performance of ATDs in regard to quality of the air inhaled by the manikin. The personal exposure effectiveness increased with the increase of the airflow rate from the ATD to a constant maximum value. A further increase......Personalized ventilation (PV) aims to provide clean air to the breathing zone of occupants. Its performance depends to a large extent on the supply air terminal device (ATD). Five different ATDs were developed, tested and compared. A typical office workplace consisting of a desk with mounted ATDs...... was simulated in a climate chamber. A breathing thermal manikin was used to simulate a human being. Experiments at room air temperatures of 26 and 20 deg.C and personalized air temperatures of 20 deg.C supplied from the ATDs were performed. The flow rate of personalized air was changed from less than 5 up to 23...

  11. Ventilation, indoor air quality, and health in homes undergoing weatherization.

    Science.gov (United States)

    Francisco, P W; Jacobs, D E; Targos, L; Dixon, S L; Breysse, J; Rose, W; Cali, S

    2017-03-01

    Ventilation standards, health, and indoor air quality have not been adequately examined for residential weatherization. This randomized trial showed how ASHRAE 62-1989 (n=39 houses) and ASHRAE 62.2-2010 (n=42 houses) influenced ventilation rates, moisture balance, indoor air quality, and self-reported physical and mental health outcomes. Average total airflow was nearly twice as high for ASHRAE 62.2-2010 (79 vs. 39 cfm). Volatile organic compounds, formaldehyde and carbon dioxide were all significantly reduced for the newer standard and first-floor radon was marginally lower, but for the older standard, only formaldehyde significantly decreased. Humidity in the ASHRAE 62.2-2010 group was only about half that of the ASHRAE 62-1989 group using the moisture balance metric. Radon was higher in the basement but lower on the first floor for ASHRAE 62.2-2010. Children in each group had fewer headaches, eczema, and skin allergies after weatherization and adults had improvements in psychological distress. Indoor air quality and health improve when weatherization is accompanied by an ASHRAE residential ventilation standard, and the 2010 ASHRAE standard has greater improvements in certain outcomes compared to the 1989 standard. Weatherization, home repair, and energy conservation projects should use the newer ASHRAE standard to improve indoor air quality and health. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Indoor Air Quality and Ventilation in Residential Deep Energy Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-06-01

    Because airtightening is a significant part of Deep Energy Retrofits (DERs), concerns about ventilation and Indoor Air Quality (IAQ) have emerged. To investigate this, ventilation and IAQ were assessed in 17 non-smoking California Deep Energy Retrofit homes. Inspections and surveys were used to assess household activities and ventilation systems. Pollutant sampling performed in 12 homes included six-day passive samples of nitrogen dioxide (NO2), formaldehyde and air exchange rate (AER); time-resolved data loggers were used to measure particle counts. Half of the homes provided continuous mechanical ventilation. Despite these homes being twice as airtight (3.0 and 7.6 ACH50, respectively), their median AER was indistinguishable from naturally vented homes (0.36 versus 0.37 hr-1). Numerous problems were found with ventilation systems; however, pollutant levels did not reach levels of concern in most homes. Ambient NO2 standards were exceeded in some gas cooking homes that used legacy ranges with standing pilots, and in Passive House-style homes without range hoods exhausted to outside. Cooking exhaust systems were installed and used inconsistently. The majority of homes reported using low-emitting materials, and formaldehyde levels were approximately half those in conventional new CA homes (19.7 versus 36 μg/m3), with emissions rates nearly 40percent less (12.3 versus 20.6 μg/m2/hr.). Presence of air filtration systems led to lower indoor particle number concentrations (PN>0.5: 8.80E+06 PN/m3 versus 2.99E+06; PN>2.5: 5.46E+0.5 PN/m3 versus 2.59E+05). The results indicate that DERs can provide adequate ventilation and IAQ, and that DERs should prioritize source control, particle filtration and well-designed local exhaust systems, while still providing adequate continuous ventilation.

  13. Centrifugal Blower for Personal Air Ventilation System (PAVS) - Phase 1

    Science.gov (United States)

    2015-02-01

    functionality. 15. SUBJECT TERMS COOLING SBIR REPORTS AXIAL FLOW FANS OFF THE SHELF EQUIPMENT BLOWERS LIGHTWEIGHT CENTRIFUGAL FORCE...HEAT STRESS (PHYSIOLOGY) AIR FLOW VENTILATION PORTABLE EQUIPMENT PERSONAL COOLING SYSTEMS EFFICIENCY EVAPORATION INTEGRATED SYSTEMS PROTOTYPES...gH Vn ad s ad s 4 1 4 3     is angular speed (2rpm) V is volumetric flow rate Had is the fan pumping head (in meters) g is the

  14. HVAC; Heating, Ventilation, Air Conditioning - Aerosol Duct Sealant

    Science.gov (United States)

    2016-09-01

    Approved for public release: distribution unlimited TDS-NAVFAC-EXWC-PW-1603 Sep 2016 HVAC ; Heating, Ventilation, Air Conditioning - Aerosol...energy consumption, depending on the HVAC system type and the location of the ducts that were sealed. The cost effectiveness of the technology is...Although several studies have been done on the effectiveness of sealing leaky HVAC ductwork with aerosol duct sealant, few studies have been done on

  15. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    OpenAIRE

    H. Mirinejad; Sadati, S.H.; M Ghasemian; H. Torab

    2008-01-01

    Problem statement: Heating, Ventilating and Air Conditioning (HVAC) systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort fiel...

  16. Transmission of exhaled air between occupants in rooms with personalized and underfloor ventilation

    DEFF Research Database (Denmark)

    Cermak, Radim; Melikov, Arsen Krikor

    2004-01-01

    in rooms. The concentration of exhaled air from one occupant was measured in air inhaled by another occupant who used or did not use personalized ventilation. The results showed that the type of personalized ventilation, together with the throw height of underfloor ventilation, affects mixing...

  17. Air Distribution and Ventilation Effectiveness in a room with Floor/Ceiling Heating and Mixing/Displacement Ventilation

    OpenAIRE

    Wu, Xiaozhou; Fang,Lei; Olesen, Bjarne W.; Zhao, Jianing

    2014-01-01

    The present study investigated different combinations of floor/ceiling heating with mixing/displacement ventilation and their impacts on the indoor air distribution and ventilation effectiveness. Measurements were performed in a room during heating season in December. The results show that indoor vertical air temperature differences and air velocities for different hybrid systems are less than 3 C and 0.2 m/s when supply air temperature is 19 C, air change rate is 4.2 h-1, and heated surface ...

  18. Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    A. Rudd and D. Bergey

    2015-08-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.

  19. Thermal calculation method for quad-sectional regenerative air preheater%四分仓回转式空气预热器热力计算方法

    Institute of Scientific and Technical Information of China (English)

    陈昌贤; 孙奉仲; 李飞; 吴艳艳

    2014-01-01

    A new thermal calculation model for quad-sectional regenerative air preheater was investigated based on the analysis of operating mode and heat transfer characteristics of quad-sectional air preheaters.The model included two cal-culating steps:the average outlet flue gas temperature and the weighted average outlet air temperature were obtained through the first step calculation;and based on the first step calculation results, the average outlet air temperatures were obtained in right-secondary airside, primary air side and left-secondary airside respectively by the second step calcula-tion.The results showed that the maximum and minimum relative deviations between calculated values and design val-ues were 2.27% and 0.21% respectively.For a 300 MW circulating fluidized bed boiler unit with quad-sectional air preheater, the maximum and average relative deviations between calculated values and actual operation data were 4%and 1.8%respectively, the accuracy and reliability of this thermal calculation model were verified.%基于四分仓空气预热器的运行方式和传热特点的分析,建立了先合仓再分仓的热力计算模型。模型包含合仓和分仓两步计算,通过合仓计算获得平均出口烟温和有加权的平均出口风温;利用合仓计算结果进行分仓计算,获得右二次风仓、一次风仓和左二次风仓的平均出口风温。结果表明,计算值与设计值的最大相对偏差为2.27%,最小相对偏差为0.21%。以某300 MW循环流化床锅炉机组的四分仓空气预热器为实例,在4个常用工况下,计算值与实际运行数据的最大相对偏差为4%,平均相对偏差为1.8%,验证了此计算方法的准确性和可靠性。

  20. Ventilation and air-conditioning concept for CNGS underground areas

    CERN Document Server

    Lindroos, J

    2002-01-01

    The aim of the CNGS project is to prove the existence of neutrino oscillation by generating an intense neutrino beam from CERN in the direction of the Gran Sasso laboratory in Italy, where two large neutrino detectors are built to detect the neutrinos. All the components for producing the neutrino beam will be situated in the underground tunnels, service galleries and chambers. The ventilation and air-conditioning systems installed in these underground areas have multiple tasks. Depending on the operating mode and structure to be air-conditioned, the systems are required to provide fresh air, cool the machine, dehumidify areas housing sensible equipment or assure the smoke removal in a case of a fire. This paper presents the technical solutions foreseen to meet these requirements.

  1. [Sanitary and epidemiological evaluation of the ventilation and air-conditioning systems of public buildings].

    Science.gov (United States)

    Dvorianov, V V

    2012-01-01

    The microbial contamination of ventilation and air conditioning systems was examined in the administrative buildings. The author proposes a set of indicators, methods for determining the scope of investigations, as well as sampling tactics and criteria for evaluating the microbial contamination of the ventilation and air-conditioning systems. The content of yeasts and molds in the delivered air has been found to be of importance for evaluating the sanitary-and epidemiological state of ventilation systems.

  2. The air quality in ventilation installations. Practical guidelines; Qualite de l'air dans les installations aerauliques. Guide pratique

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, L. [France Air, 91 - Chilly Mazarin (France); Bianchina, M. [Unelvent, 93 - Le Bourget (France); Blazy, M. [Anjos, 01 - Torcieu (France); Boulanger, X. [Aldes, 21 - Chenove (France); Chiesa, M. [Atlantic (France); Duclos, M. [Groupe Titanair, 69 - Lyon (France); Hubert, D.; Kridorian, O. [Groupe Astato, Blanc Mesnil (France); Josserand, O. [Carrier (Belgium); Lancieux, C. [Camfil, 60 - Saint Martin Longueau (France); Lemaire, J.C. [Agence de l' Environnement et de la Maitrise de l' Energie, ADEME, 75 - Paris (France); Petit, Ph. [Compagnie Industrielle d' Applications Thermiques ( CIAT ), 75 - Paris (France); Ribot, B. [Electricite de France (EDF), 75 - Paris (France); Tokarek, S. [Gaz de France (GDF), 75 - Paris (France); Bernard, A.M.; Tissot, A. [Centre Technique des Industries Aerauliques et Thermiques (CETIAT), 69 - Villeurbanne (France)

    2004-07-01

    The present guide aims to provide design departments, maintenance companies and builders with practical guidelines and recommendations for the installation of ventilation and air-conditioning systems. The objective is to ensure good Indoor Air Quality (IAQ) and to safeguard the health and well-being of the occupants. The guide deals with aspects of design, dimensioning, installation and servicing, all of which play a major role in guaranteeing IAQ and duct-work hygiene. These steps are reviewed for the principal ventilation systems met in both residential and commercial premises. The first part presents the system and draws the attention of the user to specific points which require particular care in term of IAQ. The second part details recommended practice component by component, in respect of design, installation and servicing. Application of these simple guidelines during the various project stages is essential, in order to ensure a good IAQ in ventilation systems. Content: introduction; good ventilation; systems: exhaust ventilation, balanced ventilation, air handling unit, terminal ventilation units, impact of systems on indoor air quality, components: air inlet, air filter, heat recovery unit, heating or cooling coil, humidifier, mechanical fan unit, cowl and hybrid ventilation fan, mixing box, ventilation duct-work, air outlet and air terminal device; references.

  3. Enrichment of ventilation air methane (VAM) with carbon fiber composites.

    Science.gov (United States)

    Bae, Jun-Seok; Su, Shi; Yu, Xin Xiang

    2014-05-20

    Treatment of ventilation air methane (VAM) with cost-effective technologies has been an ongoing challenge due to its high volumetric flow rate with low and variable methane concentrations. In this work, honeycomb monolithic carbon fiber composites were developed and employed to capture VAM with a large-scale test unit at various conditions such as VAM concentration, ventilation air (VA) flow rate, temperature, and purging fluids. Regardless of inlet VAM concentrations, methane was captured at almost 100%. To regenerate the composites, the initial vacuum swing followed by combined temperature and vacuum swing adsorption (TVSA) was applied. It was found that initial vacuum swing is a control step for the final methane concentration having 5 or 11 times the VAM enrichment by one-step adsorption, which is, to our knowledge, the best performance achieved in VAM enrichment technologies worldwide. Five-time enriched VAM can be utilized as a principle fuel for lean burn turbine. Also, it can be further enriched by second step adsorption to more than 25% which then can be used for commercially available gas engines. In this way, the final product can be out of the methane explosive range (5-15%).

  4. Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

    Energy Technology Data Exchange (ETDEWEB)

    2015-08-01

    ?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.

  5. Fresh air supply in airtight, well insulated houses; Friskluftforsyning i taette, velisolerede huse

    Energy Technology Data Exchange (ETDEWEB)

    Wittchen, K.

    1988-12-01

    Modern Danish houses are often built with a great respect for insulation and air tightness. Because of this it can be necessary to install mechanical ventilation systems in order to obtain a good indoor air quality. To meet the demand for low energy consumption, air-to-air heat exchangers are often added to the ventilation systems. Heat exchangers typically operate with a thermal efficiency of 0.6-0.7. However it is possible to achieve further energy savings by preheating the cold ventilation air before it reaches the heat exchanger. This preheating could be achieved by leading the cold air through surroundings with a temperature higher than the external air temperature. Surroundings of this kind can be found in attics, crawl spaces, underground ducts etc. Analysis have been made of the preheating of the ventilation air in 3 of 6 monitored low energy houses at Hjortekaer, about 20 km north of Copenhagen. The houses each had different types of ventilation systems with heat exchangers, namely preheating in an attic, preheating in a crawl space and a traditional simple ventilation system in a low energy house. Furthermore, a theoretical analysis of the preheating in an underground duct system has been made. Investigations showed that compatibility is best between heating demand and possible energy gain when the preheating comes from a ground-connected system (crawl spaces or an underground duct system). Ventilation systems of this type will, beside the preheating gains, offer the opportunity of cooling the house in periods with high ambient temperatures. (AB) 57 p.

  6. Experimental Study of Air Distribution and Ventilation Effectiveness in a Room with a Combination of Different Mechanical Ventilation and Heating/Cooling Systems

    DEFF Research Database (Denmark)

    Olesen, Bjarne W.; Simone, Angela; Krajcik, Michal;

    2011-01-01

    Mixing and displacement ventilation are common systems in commercial buildings, while mixing ventilation is used in residential buildings. Displacement ventilation provides fresh air to the occupied zone in a more efficient way than mixing ventilation but it is important to know how well it works...... with a floor system for heating or cooling. Can, for example, a floor heating system warm up the supply air too fast and destroy the displacement effect? Will floor cooling, combined with displacement ventilation, result in too high a vertical temperature difference and too low a temperature at feet level......? The required amount of ventilation depends on the ventilation effectiveness. In standards, the recommended values for ventilation effectiveness depend on the position of the supply and exhaust device and on the difference between supply and room air temperature. Among others, for warm air heating...

  7. Effects of energy-efficient ventilation rates on indoor air quality at an Ohio elementary school

    Science.gov (United States)

    Berk, J. V.; Young, R.; Hollowell, C. D.; Turiel, I.; Pepper, J.

    1980-04-01

    A mobile laboratory was used to monitor air outdoors and at three indoor sites (two classrooms and a large multipurpose room); tests were made at three different ventilation rates. The parameters measured were outside air flow rates, odor perception, microbial burden, particulate mass, total aldehydes, carbon dioxide, ozone, and nitrogen oxides. The results of these measurements are given and compared with the existing outdoor air quality standards. Carbon dioxide concentrations increased as the ventilation rate decreased, but still did not exceed current standards. Odor perceptibility increased slightly at the lowest ventilation rate. Other pollutants showed very low concentrations, which did not change with reductions in ventilation rate.

  8. [Bipolar ionisation of indoor air through ion generators mountable into inflow ventilation and conditioning].

    Science.gov (United States)

    Dudarev, A A; Spichkin, G L; Denisikhina, D M; Burtsev, S I

    2010-01-01

    Experimental studies and digital modelling of artificial indoor air ionisation through bipolar ionisers mountable into inflow ventilation and conditioning proved possible creation of continuous even bipolar ion background in indoor air, similar to the natural one.

  9. Influence of Ventilation Ratio on Desiccant Air Conditioning System's Efficiency Performance

    Science.gov (United States)

    Tran, Thien Nha; Akisawa, Atsushi; Kashiwagi, Takao; Hamamoto, Yoshinori

    Ventilation air is a concern for engineers since ventilated air controls indoor air contamination; additional ventilation, however, increases the energy consumption of buildings. The study investigates the energy efficiency performance of the desiccant dehumidification air conditioning system in the context of ventilation for a hot-humid climate such as summer in Japan. The investigation focuses on the variable ratio of ventilation air as required by the application of air conditioning system. The COP of the desiccant air conditioning system is determined. The evaluation is subsequently performed by comparing the desiccant based system with the conventional absorption cooling system and the vapor compression cooling system. Based on 12 desiccant rotor simulations, it is found that the desiccant regeneration temperature required varies between 47°C to 85°C as ventilation ratio increases from 0. 0 to 100%, and up to 52. 5°C as the ventilation ratio achieves 14%. The heat required for regenerating desiccant accounts for 55% and higher of the system's total heat consumption; the system is expected to be energy efficient by using wasted heat from the absorption chiller for desiccant regeneration; and its energy efficiency expands as the ratio of ventilation air rises above 15% compared with the conventional absorption cooling system. The energy efficiency also benefits as the ratio rises beyond 70% against the conventional vapor compression cooling system.

  10. 8th International Symposium on Heating, Ventilation and Air Conditioning

    CERN Document Server

    Zhu, Yingxin; Li, Yuguo; Vol.1 Indoor and Outdoor Environment; Vol.2 HVAC&R Component and Energy System; Vol.3 Building Simulation and Information Management

    2014-01-01

    Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proce...

  11. Internal air ventilated crawl-space : an evaluation of two manufactures

    OpenAIRE

    Rönngren, Andreas

    2002-01-01

    This Diploma work investigates internal air ventilated crawl-space in respect to construction and damp. The Diploma work assumes from a general description of crawl-space and general dump problems in ground construction. An internal air ventilated crawl-space is a construction where you take the ventilation air from the building and bring it down to the crawl-space and lets the air circulate before it passes through a retaining aggregate on the way out from the crawl-space. In this matter yo...

  12. Ventilation System Type and the Resulting Classroom Temperature and Air Quality During Heating Season

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows...... windows. Classrooms with automatically operable windows and exhaust fan and with mechanical ventilation systems achieved the best thermal environment and air quality during heating season among all classrooms examined....... with and without exhaust fan and by mechanical ventilation system. Temperature, relative humidity, carbon dioxide (CO2) concentration and opening of windows were continuously monitored for one month during heating season in 2012. Classroom with manually operable windows had the highest carbon dioxide concentration...

  13. Natural Ventilation of Indoor Air Temperature: A Case Study of the Traditional Malay House in Penang

    Directory of Open Access Journals (Sweden)

    Ahmad S. Hassan

    2010-01-01

    Full Text Available Problem statement: It was the aim of the study to analyze the level of performance of natural air ventilation with a case study of the traditional Malay house in Penang, Malaysia. This study provided information on the architectural design in relation to natural air ventilation. It promoted passive design in contrast to most housing design which has poor natural air ventilation because the design was orientated to energy consumption that slightly more than one third of the electric energy was used for heating, ventilating and air conditioning systems. Approach: This analysis used quantitative method which measured temperature, humidity and wind speed of the traditional house. The result indicated the level of performance of cross air ventilation and stack effect. Results: The analysis showed that the traditional house has a design integrated with natural air ventilation system. The indoor house temperature and relative humidity had slightly lower than its outdoor area. However, the indoor area had lower wind speed level than the outdoor area. Conclusion: The study showed that maximum openings on the building walls created high air intakes outside the house to give poor performance of stack effect. The design had more emphasis to cross air ventilation.

  14. Can we establish relationship between outdoor air ventilation and health based on the published epidemiological data?

    DEFF Research Database (Denmark)

    Carrer, Paolo; Wargocki, Pawel; Fanetti, Annaclara

    2015-01-01

    , multidisciplinary review was carried out of the scientific literature on health and outdoor air ventilation in non-industrial indoor environments (not covered by previous reviews on this topic) and of major reviews on this topic. The results show, that effects on health were seen for wide range of ventilation rates......Appropriate exposure control is prerogative for reducing the burden of disease (BOD) due to inadequate air quality indoors (IAQ). Ventilation with outdoor air is one of the available exposure control methods and is widespread. It is often assumed that this method will bring tangible effects...... on health. This paper examines whether the available archival epidemiological evidence provides information on the link between outdoor air ventilation and health that can be used for regulative purposes, when ventilation requirements for non-industrial built environments are set. To achieve this goal...

  15. The effect of ventilation on the indoor air concentration of PCB

    DEFF Research Database (Denmark)

    Lyng, Nadja; Gunnarsen, Lars Bo; Andersen, Helle Vibeke

    2015-01-01

    The impact of increased ventilation on polychlorinated biphenyl (PCB) air concentration by installation of mechanical balanced ventilation units was studied. The intervention was carried out in three PCB-contaminated rooms; one classroom in an elementary school and two small bedrooms...... in an apartment in a residential building. In the classroom, the air exchange rate (ACH) was raised from 0.2 (without mechanical ventilation) to 5.5 /h during the intervention. In the two bedrooms, the highest ACH was 6.6 /h and 0.5 /h without mechanical ventilation. The corresponding concentration decrease...... achieved from the intervention was 30% and in one of the bedrooms 45%. Emissions of PCB rose dramatically during periods of increased ventilation as the drop in concentration did not match the increased ACH. When ventilation in the bedrooms was increased incrementally from 0.5 to 2.2, 4.5, and 6.6 /h...

  16. 组合式空气预热器振动原因分析及解决措施%CAUSE ANALYSIS FOR THE VIBRATION OFCOMBINED AIR PREHEATER AND THE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    颜祥富; 侯杰; 龙运国

    2012-01-01

    某组合式空气预热器试运行时产生强烈振动,文章对空气预热器产生震动的原因进行了分析,指出卡门涡流是预热器产生振动的主要原因,因为当气流横向绕流管束时,卡门涡流的交替脱落会引起空气预热器中气柱的振动.当漩涡的脱落频率(fK)与管箱的声学驻波振动频率接近或一致时,会诱发强烈的管箱声学驻波振动,造成空气预热器管箱的共振.为了消除振动,对预热器进行了改造:沿换热管方向安装消振隔板,将预热器从上至下贯通均等分成3个气室(相当于减小气室宽度),以提高气室固有频率及振风量.改造后预热器的卡门涡流频率和气室固有频率不会重合,也就不会产生声学共振.通过改造,该预热器消除了振动,恢复了正常的运行,确保炼化加热炉高效、长周期安全稳定运转.%Certain combined air preheater produced strong vibration during test run. This paper analyzes the causes for the vibration of the air preheater and points out that Karman vortex is the main reason for the vibration of the preheater because the alternating shedding of Karman vortex may cause the column vibration of the air preheater when the air flows through the tube bundle transversely. When the vortex shedding frequency ( /k ) and the frequency of the acoustic standing wave vibration of the tube box is close to each other or consistent, strong acoustic standing wave vibration of the tube box will be induced. And this may cause the resonance of the tube box of the air preheater. In order to eliminate the vibration, the preheater has been transformed. Vibration elimination separators are installed along the heat transfer tube direction and the preheater is divided into three equal chambers from the top to the bottom, which equals to reducing the width of the chamber. This may increase the natural frequency of the chamber and the vibration air volume. After the transformation, the Karman vortex

  17. The Contaminant Distribution in a Ventilated Room with Different Air Terminal Devices

    DEFF Research Database (Denmark)

    Heiselberg, Per; Nielsen, Peter V.

    of the jets and the comfort requirements applied to measured air velocities in the occupied zone. Normalized concentration distribution in the test room is determined along a vertical line through the middle of the room as a function of the air exchange rate and the density of the tracer gas. The relative......The room ventilation is investigated for three different air terminal devices under isothermal conditions. Velocity distribution in the occupied zone is measured for each air terminal device at different air exchange rates. The maximum air exchange rate is determined on the base of both the throw...... ventilation efficiency, , based on the room average concentration is also determined as a function of the air exchange rate and the density of the tracer gas. The influence from the position of the return opening on the relative ventilation efficiency is found for one air terminal device....

  18. Air temperature regulation in mine workings on the basis of local and block ventilation systems with boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Bobrov, A.I.; Batmanov, Y.K.; Lunev, S.G.; Martynov, A.A. [Makeyevka Safety in Mines Research Institute, Makeyevka (Ukraine)

    1997-12-31

    The thermal factor is one of the main factors complicating coal mining in the Donetsk Basin (Ukraine). Local ventilation systems (small diameter boreholes to improve ventilation in individual headings at deep levels) and block ventilation systems (large diameter boreholes for ventilation and air temperature control in independently mined blocks and panels) are discussed. 4 refs., 3 figs.

  19. Carbon fibre composite for ventilation air methane (VAM) capture

    Energy Technology Data Exchange (ETDEWEB)

    Thiruvenkatachari, Ramesh [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Su Shi, E-mail: Shi.Su@csiro.au [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Yu Xinxiang [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia)

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment.

  20. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    H. Mirinejad

    2008-01-01

    Full Text Available Problem statement: Heating, Ventilating and Air Conditioning (HVAC systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort field is introduced, followed by a review and comparison of the main existing control techniques used in HVAC systems to date. Results: The present overview shows that intelligent controllers which are based on the human sensation of thermal comfort have a better performance in providing thermal comfort as well as energy saving than the traditional controllers and those based on a model of the HVAC system. Conclusion: Such an overview provides an insight into current control methods in HVAC systems and can help scholars and HVAC learners to have the comprehensive information about a variety of control techniques in the field of HVAC and therefore to better design a proper controller for their work

  1. Carbon fibre composite for ventilation air methane (VAM) capture.

    Science.gov (United States)

    Thiruvenkatachari, Ramesh; Su, Shi; Yu, Xin Xiang

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment.

  2. New Air Cleaning Strategies for Reduced Commercial Building Ventilation Energy ? FY11 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sidheswaran, Meera; Destaillats, Hugo; Cohn, Sebastian; Sullivan, Douglas P.; Fisk, William J.

    2011-10-31

    The research carried out in this project focuses on developing novel volatile organic compounds (VOCs) air cleaning technologies needed to enable energy-saving reductions in ventilation rates. we targeted a VOC air cleaning system that could enable a 50% reduction in ventilation rates. In a typical commercial HVAC system that provides a mixture of recirculated and outdoor air, a VOC air cleaner in the supply airstream must have a 15% to 20% VOC removal efficiency to counteract a 50% reduction in outdoor air supply.

  3. Experimental analysis of fuzzy controlled energy efficient demand controlled ventilation economizer cycle variable air volume air conditioning system

    Directory of Open Access Journals (Sweden)

    Rajagopalan Parameshwaran

    2008-01-01

    Full Text Available In the quest for energy conservative building design, there is now a great opportunity for a flexible and sophisticated air conditioning system capable of addressing better thermal comfort, indoor air quality, and energy efficiency, that are strongly desired. The variable refrigerant volume air conditioning system provides considerable energy savings, cost effectiveness and reduced space requirements. Applications of intelligent control like fuzzy logic controller, especially adapted to variable air volume air conditioning systems, have drawn more interest in recent years than classical control systems. An experimental analysis was performed to investigate the inherent operational characteristics of the combined variable refrigerant volume and variable air volume air conditioning systems under fixed ventilation, demand controlled ventilation, and combined demand controlled ventilation and economizer cycle techniques for two seasonal conditions. The test results of the variable refrigerant volume and variable air volume air conditioning system for each techniques are presented. The test results infer that the system controlled by fuzzy logic methodology and operated under the CO2 based mechanical ventilation scheme, effectively yields 37% and 56% per day of average energy-saving in summer and winter conditions, respectively. Based on the experimental results, the fuzzy based combined system can be considered to be an alternative energy efficient air conditioning scheme, having significant energy-saving potential compared to the conventional constant air volume air conditioning system.

  4. Air Distribution in Aircraft Cabins Using Free Convection Personalized Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The aim of the ventilation system is to control cross infection in an aircraft cabin if one or a number of the passengers are “source patients” (source of airborne disease). The Personalized Ventilation described in this text is of the type mentioned in “Free Convection Personalized Ventilation”....

  5. The results of air treatment process modeling at the location of the air curtain in the air suppliers and ventilation shafts

    Directory of Open Access Journals (Sweden)

    Nikolaev Aleksandr

    2017-01-01

    Full Text Available In the existing shaft air heater installations (AHI, that heat the air for air suppliers in cold seasons, a heater channel is used. Some parts of the air from the heater go to the channel, other parts are sucked through a pithead by the general shaft pressure drawdown formed by the main ventilation installation (MVI. When this happens, a mix of two air flows leads to a shaft heat regime violation that can break pressurization of intertubular sealers. The problem of energy saving while airing underground mining enterprises is also very important. The proposed solution of both tasks due to the application of an air curtain is described in the article. In cold seasons the air treatment process should be used and it is offered to place an air curtain in the air suppliers shaft above the place of interface of the calorifer channel to a trunk in order to avoid an infiltration (suction of air through the pithead. It’s recommended to use an air curtain in a ventilation shaft because it reduces external air leaks thereby improving energy efficiency of the MVI work. During the mathematical modeling of ventilation and air preparation process (in SolidWorks Flowsimulation software package it was found out that the use of the air curtain in the air supply shaft can increase the efficiency of the AHI, and reduce the electricity consumption for ventilation in the ventilation shaft.

  6. Exposure to aerosol and gaseous pollutants in a room ventilated with mixing air distribution

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Ondráček, Jakub; Ždímal, Vladimír

    2016-01-01

    The present study investigates the aerosol and gas dispersal in a mechanically ventilated room and the personal exposure to these contaminants. The study was performed in a full-scale climate chamber. The room was air conditioned via mixing total volume ventilation system. The room occupancy...... of the thermal manikin were measured. The results showed higher exposure to the contaminants measured at the breathing zone than at the ambient air. The behaviour of the tracer gas and the aerosols was similar....

  7. Experimental analysis of indoor air quality improvement achieved by using a Clean-Air Heat Pump (CAHP) air-cleaner in a ventilation system

    DEFF Research Database (Denmark)

    Sheng, Ying; Fang, Lei; Nie, Jinzhe

    2017-01-01

    This study investigated the air purification effect of a Clean-Air Heat Pump (CAHP) air-cleaner which combined a silica gel rotor with a heat pump to achieve air cleaning, heating and ventilation in buildings. The experiments were conducted in a field laboratory and compared a low outdoor air...

  8. Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air%使用加热空气的预混天然气催化燃烧的实验研究

    Institute of Scientific and Technical Information of China (English)

    许考; 刘中良; 何洪; 程水源; 马重芳

    2007-01-01

    In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC),NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied.Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃,100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.

  9. The effect of a personalized ventilation system on perceived air quality and SBS symptoms

    DEFF Research Database (Denmark)

    Kaczmarczyk, Jan; Zeng, Q.; Melikov, Arsen Krikor

    2002-01-01

    Perceived air quality, SBS symptoms and performance were studied with 30 human subjects. Experiments were performed in an office set-up with six workplaces, each equipped with a Personalized Ventilation System (PVS). Each PVS allowed the amount of supply air and its direction to be controlled...... condition in regard to perceived air quality, perception of freshness and intensity of SBS symptoms was when PVS supplied outdoor air at 20 deg.C. Perceived air quality in this case was significantly better (p...

  10. Use of perforated acoustic panels as supply air diffusers in diffuse ceiling ventilation systems

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Kazemi, Seyed Hossein; Ardkapan, Siamak Rahimi

    manufacturing perforated acoustic panels for the last 13 years. The panels can be used not only in applications related to acoustics but also as low pressure drop supply air diffusers, particularly in diffuse ceiling ventilation systems. The present study verifies on a theoretically level the performance......Ventilation is needed for diluting and removing the contaminants, odour and excess heat from the building interior. It is important that the inhabitants perceive the ventilated spaces as comfortable. Therefore, the supply air should reach all parts of the occupied zones. Troldtekt has been...

  11. Use of perforated acoustic panels as supply air diffusers in diffuse ceiling ventilation systems

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Kazemi, Seyed Hossein; Ardkapan, Siamak Rahimi

    Ventilation is needed for diluting and removing the contaminants, odour and excess heat from the building interior. It is important that the inhabitants perceive the ventilated spaces as comfortable. Therefore, the supply air should reach all parts of the occupied zones. Troldtekt has been...... manufacturing perforated acoustic panels for the last 13 years. The panels can be used not only in applications related to acoustics but also as low pressure drop supply air diffusers, particularly in diffuse ceiling ventilation systems. The present study verifies on a theoretically level the performance...

  12. Application of high strength sonic soot blower in air preheater of 1 000 MW units%高强声波吹灰器在1000 MW机组空预器中的应用

    Institute of Scientific and Technical Information of China (English)

    李彦民; 王俊杰

    2016-01-01

    There are some problems existed in the running of air preheater in CLP vote of Henan Electric Power co. LTD. ,Pingdingshan Power 2 x 1 000 MW ultra supercritical units. The air preheater had a large amount of dust ,so the resistance increased which is one of the important reasons affecting the safe and economic opera-tion. The sonic soot blower is applied in air preheater to prevent the dust and its effect is analyzed. The practi-cal application results show that the efficient acoustic wave sootblower are deposited in the air preheater and has obvious effect, the safety benefit, economic benefit and social benefit are remarkable.%介绍了中电投河南电力有限公司平顶山发电分公司2×1000 MW超超临界机组空预器在运行中出现的大量积灰情况,空预器阻力的大幅增加是影响机组安全、经济运行的重要原因。分析通过空预器加装声波吹灰器后对防止空预器大量积灰的效果,根据实践应用结果表明,高效声波吹灰器对空预器积灰有明显效果,安全效益、经济效益及社会效益显著。

  13. 350 MW超临界直流锅炉空预器堵塞原因分析及处理%Analysis and Treatment of Blockage in Air Preheater of 350 MW Supercritical Once Through Boiler

    Institute of Scientific and Technical Information of China (English)

    崔鹏

    2016-01-01

    The selective catalytic reduction (SCR) by reducing agent of ammonia (NH3) is used to achieve the purpose of removal of NOx in flue gas in boiler denitration system in Hohhot Thermal Power Plant. In the operation of ammonia and NOx cannot all mix, escape is inevitable, when the escape rate of overweight ammonia and sulfur trioxide in flue gas reaction generated hydrogen sulfate ammonia block in air preheater, due to differential pressure increasing of the air preheater. The application of ammonium hydrogen sulfate physical properties will be ammonia decomposition hydrogen sulfate, air preheater body heat will ammonia gasification hydrogen sulfate, eliminating air preheater clogging. Experience can be used as reference in the same type unit.%呼和浩特热电厂2×350 MW机组锅炉脱硝系统采取选择性催化还原法(SCR),使用还原剂氨(NH3)来达到除去烟气中NOx的目的。运行中氨气和NOx不可能全部混合,逃逸无法避免,当逃逸率超标时,氨气与烟气中三氧化硫反应生成硫酸氢铵堵塞空预器,导致空预器前后差压增大。对此根据硫酸氢铵的物理性质,采用空预器降风量升烟温的方法将硫酸氢铵气化,消除空预器堵塞,经验可供同类型机组参考。

  14. Preheating in New Inflation

    CERN Document Server

    Desroche, M; Kratochvil, J; Linde, Andrei D; Desroche, Mariel; Felder, Gary N.; Kratochvil, Jan M.; Linde, Andrei

    2005-01-01

    During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We do a full analysis of preheating in new inflation, using a combination of analytical and numerical methods. We find that the decay of the homogeneous component of the inflaton field and the resulting process of spontaneous symmetry breaking in the simplest models of new inflation usually occurs almost instantly: for the new inflation on the GUT scale it takes only about 5 oscillations of the field distribution. The decay of the homogeneous inflaton field is so efficient because of a combined effect of tachyonic preheating and parametric resonance. At that stage, the homogeneous oscillating inflaton field decays into a collection of waves of the inflaton field, with a typical wavelength of the order of the inverse inflaton mass. This stage usually is followed by a long st...

  15. Summarized Data of Test Space Heating, Ventilation and Air Conditioning Inspections from the Building Assessment Survey and Evaluation Study

    Science.gov (United States)

    Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

  16. 煤气锅炉空气预热器腐蚀原因及对策%Reason and Treatment of Air Preheater Corrosion of Gas-Fired Boiler

    Institute of Scientific and Technical Information of China (English)

    王锐; 刘启学; 孙保顺

    2013-01-01

    结合对75t煤气锅炉低温段空气预热器的改造实例,阐述了煤气锅炉低温段空气预热器因锅炉负荷变化、掺烧焦炉煤气增大等因素而引起的低温段空气预热器低温腐蚀现象,分析了低温段空气预热器腐蚀损坏的原因并提出了相应的预防改进措施。%Combine a instance of the remould to the air preheater of the 75 t gas-fired boiler low temperature segment in Xingtai Iron& Steel Corp .Ltd., describe the actualities of air preheater corrosion of gas-fired boiler be-cause of the boiler load carries change and coke-oven gas flow enlarged etc ..Reasons of air preheater corrosion was an-alyzed, and the solution measures are proposed .

  17. Ventilation, indoor air quality, and human health and comfort in dwellings and day-care centers

    Energy Technology Data Exchange (ETDEWEB)

    Ruotsalainen, R.

    1995-12-31

    The objective of the study was to assess the actual ventilation and indoor air quality in the Finnish building stock (dwellings and day-care centers) with special reference to the existing guideline values. Furthermore, the objective was to evaluate the occurrence of symptoms and perceptions among occupants (adult residents, children, workers) in relation to ventilation system, ventilation rate and dampness. The measurements of ventilation and indoor air quality in the dwellings and day-care centers included ventilation rate, CO{sub 2} concentration, and temperature and humidity. Self- and parent-administered questionnaires were distributed to the occupants inquiring their personal characteristics, occurrence of symptoms of interest, perceived indoor air quality and details of their home and work environments. Airflows and air change rates varied remarkably both in the dwellings and day-care centers. In the majority of the dwellings and day-care centers, the Finnish guideline values of ventilation rates were not achieved. No consistent associations were observed between the magnitude of mechanical ventilation rates and the occurrence of eye, respiratory, skin and general symptoms, that is, symptoms of sick building syndrome (SBS) among the day-care workers. The results indicate that there is much room for improvement in the ventilation and indoor air quality of Finnish dwellings and day-care centers. The control of ventilation, temperature and humidity and the prevention of water damage are important issues on which to concentrate in the future. There is need to improve the quality in all phases of construction: design, installation, adjustment, operation, and maintenance

  18. A Simplified Tool for Predicting the Thermal Behavior and the Energy Saving Potential of Ventilated Windows

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per Kvols; Larsen, Olena Kalyanova

    2016-01-01

    windows in the early design stage. The simplified tool is developed to treat different ventilation modes: pre-heating, self-cooling and by–pass, and an operational strategy is established to determine the most energy efficient mode in each time step. Cavity air temperature and energy demand are calculated...

  19. Measuring Air Temperature in Glazed Ventilated Facades in the Presence of Direct Solar Radiation

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Zanghirella, Fabio; Heiselberg, Per

    2007-01-01

    A distinctive element of buildings with a double glazed façade is naturally or mechanically driven flow in a ventilated cavity. Accurate air temperature measurements in the cavity are crucial to evaluate the dynamic performance of the façade, to predict and control its behavior as a significant...... part of the complete ventilation system. Assessment of necessary cooling/heating loads and of the whole building energy performance will then depend on the accuracy of measured air temperature. The presence of direct solar radiation is an essential element for the façade operation, but it can heavily...... irradiance, in order to achieve an accurate and reliable way to measure the air temperature reducing the error caused by radiation. Experiments include bare thermocouple, naturally and mechanically ventilated shielded thermocouples, mechanically ventilated thermocouple with double shielding, silver coated...

  20. Preheating after modular inflation

    Science.gov (United States)

    Barnaby, Neil; Bond, J. Richard; Huang, Zhiqi; Kofman, Lev

    2009-12-01

    We study (p)reheating in modular (closed string) inflationary scenarios, with a special emphasis on Kähler moduli/Roulette models. It is usually assumed that reheating in such models occurs through perturbative decays. However, we find that there are very strong non-perturbative preheating decay channels related to the particular shape of the inflaton potential (which is highly nonlinear and has a very steep minimum). Preheating after modular inflation, proceeding through a combination of tachyonic instability and broad-band parametric resonance, is perhaps the most violent example of preheating after inflation known in the literature. Further, we consider the subsequent transfer of energy to the standard model sector in scenarios where the standard model particles are confined to a D7-brane wrapping the inflationary blow-up cycle of the compactification manifold or, more interestingly, a non-inflationary blow-up cycle. We explicitly identify the decay channels of the inflaton in these two scenarios. We also consider the case where the inflationary cycle shrinks to the string scale at the end of inflation; here a field theoretical treatment of reheating is insufficient and one must turn instead to a stringy description. We estimate the decay rate of the inflaton and the reheat temperature for various scenarios.

  1. Human Response to Ductless Personalised Ventilation: Impact of Air Movement, Temperature and Cleanness on Eye Symptoms

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Fillon, Maelys; Bivolarova, Maria;

    2013-01-01

    The performance of ductless personalized ventilation (DPV) in conjunction with displacement ventilation (DV) was studied in relation to peoples’ health, comfort and performance. This paper presents results on the impact of room air temperature, using of DPV and local air filtration on eye blink...... rate and tear film quality. In a test room with DV and six workstations 30 human subjects were exposed for four hours to each of the following 5 experimental conditions: 23 °C and DV only, 23 °C and DPV with air filter, 29 °C and DV only, 29 °C and DPV, and 29 °C and DPV with air filter. At warm...... environment facially applied individually controlled air movement of room air, with or without local filtering, did not have significant impact on eye blink frequency and tear film quality. The local air movement and air cleaning resulted in increased eye blinking frequency and improvement of tear film...

  2. Seat headrest-incorporated personalized ventilation: Thermal comfort and inhaled air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Ivanova, T.; Stefanova, G.

    2012-01-01

    and a decreased risk of airborne cross-infection when SHPV is used. Subjects assessed the air movement and the cooling provided by the SHPV as acceptable. Acceptability was unchanged over in time and increased with the increase of the air temperature. No draught was reported. The SHPV can be used in spaces where......The performance of personalized ventilation with seat headrest-mounted air supply terminal devices (ATD), named seat headrest personalized ventilation (SHPV), was studied. Physical measurements using a breathing thermal manikin were taken to identify its ability to provide clean air to inhalation...... depending on design, shape, size and positioning of the ATD, flow rate and temperature of personalized air, room temperature, clothing thermal insulation of the manikin, etc. Tracer gas was mixed with the room air. The air supplied by the SHPV was free of tracer gas. Tracer gas concentration in the air...

  3. Bringing coal preheating in drum dryers to a commercial level

    Energy Technology Data Exchange (ETDEWEB)

    Babanin, B.I.; Proushin, Yu.E.; Dinel' t, V.M.; Nikolaeva, V.Z.; Shabarshova, Yu.V.; Patrushev, A.N.; Vodop' yanov, A.G.; Vlasov, V.S.; Sementin, V.P.

    1988-10-01

    Discusses operation of a system for coal charge preheating used in Western Siberia since 1965. It is the first coal preheating system constructed in the USSR. The following aspects of system operation are discussed: composition of combustion gases used for coal drying, drying temperature, consumption rate of combustion gases depending on coal moisture content, flue gas recirculation system, transport and storage of dried coal, methods for dust separation (wet and dry), air pollution from coal dryers, and efficiency of air pollution control. Operation of the coal preheating system shows that one-stage coal drying and preheating is economic but associated with increased investment (construction cost) and with increased coal comminution. Large one-stage dryers also cause irregular coal preheating depending on distribution of coal grain size (with overheating of coal fines). Recommendations for design modifications of one-stage dryers are made. 3 refs.

  4. Ventilation patterns of the songbird lung/air sac system during different behaviors.

    Science.gov (United States)

    Mackelprang, Rebecca; Goller, Franz

    2013-10-01

    Unidirectional, continuous airflow through the avian lung is achieved through an elaborate air sac system with a sequential, posterior to anterior ventilation pattern. This classical model was established through various approaches spanning passively ventilated systems to mass spectrometry analysis of tracer gas flow into various air sacs during spontaneous breathing in restrained ducks. Information on flow patterns in other bird taxa is missing, and these techniques do not permit direct tests of whether the basic flow pattern can change during different behaviors. Here we use thermistors implanted into various locations of the respiratory system to detect small pulses of tracer gas (helium) to reconstruct airflow patterns in quietly breathing and behaving (calling, wing flapping) songbirds (zebra finch and yellow-headed blackbird). The results illustrate that the basic pattern of airflow in these two species is largely consistent with the model. However, two notable differences emerged. First, some tracer gas arrived in the anterior set of air sacs during the inspiration during which it was inhaled, suggesting a more rapid throughput through the lung than previously assumed. Second, differences in ventilation between the two anterior air sacs emerged during calling and wing flapping, indicating that adjustments in the flow pattern occur during dynamic behaviors. It is unclear whether this modulation in ventilation pattern is passive or active. This technique for studying ventilation patterns during dynamic behaviors proves useful for establishing detailed timing of airflow and modulation of ventilation in the avian respiratory system.

  5. Multivariate analysis comparing microbial air content of an air-conditioned building and a naturally ventilated building over one year

    Science.gov (United States)

    Parat, Sylvie; Perdrix, Alain; Fricker-Hidalgo, Hélène; Saude, Isabelle; Grillot, Renee; Baconnier, Pierre

    Heating, ventilation and air-conditioning (HVAC) may be responsible for the production and spread of airborne microorganisms in office buildings. In order to compare airborne microbiological flora in an air-conditioned building with that in a naturally ventilated building, eight sets of measurements were made over a 1-year period. Concurrently with other environmental measurements, air samples were collected in each building, from three offices and from the outdoor air, using the Andersen single-stage sampler. Three different media were used to culture fungi, staphylococci and mesophilic bacteria. Multivariate analysis revealed a group of offices more contaminated than others, and a marked seasonal variation in fungal concentrations. A comparison of mean levels of microorganisms measured in the two buildings showed that the air microbial content was significantly higher and more variable in the naturally ventilated building than in the air-conditioned building. Moreover, in the naturally ventilated building, the interior fungal content was strongly dependent on the outdoor content, while in the air-conditioned building fungal concentrations remained constant despite significant variations measured outside. This was confirmed by a statistical comparison of the correlation coefficients between indoor and outdoor concentrations. No difference was observed regarding gaseous pollutants and temperature, but relative humidity was significantly higher in the air-conditioned building. The effect of HVAC was to prevent the intake of outdoor particles and to dilute the indoor concentrations. These results are consistent with the presence of high-efficiency filters and a steam humidifier in the HVAC system under study.

  6. Thermal comfort and indoor air quality in rooms with integrated personalized ventilation and under-floor air distribution systems

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar ., S. C.; Melikov, Arsen Krikor

    2011-01-01

    A comprehensive study comprising physical measurements and human subject experiments was conducted to explore the potential for improving occupants' thermal comfort and indoor air quality (IAQ) using a personalized ventilation (PV) system combined with an under-floor air distribution(UFAD) system...

  7. 垃圾焚烧发电厂一次风预热方式的比较分析%Comparison of Preheating Ways of Primary Air in Waste Incineration Power Plants

    Institute of Scientific and Technical Information of China (English)

    李军; 严圣军; 陈竹; 王占磊

    2012-01-01

    A comparison of heating medium in phase II of primary air preheater by ways of superheat steam and drum saturated steam for waste incineration power plants were carried out. The results showed that comparing with drum saturated steam, the weight of steam extraction with superheat steam decreased by 20. 8%, the heat quantity decreased by 8. 7%, the steam flow into the turbine increased, the heat exchanging area in phase II of the preheater can be reduced by about 20%, and the cost can be reduced by about 10%. The superheat steam has advantages of small investment cost, small steam consumption, and higher heat effective utilization. According to waste characteristic, incineration scale and control policy, it could give a reference to select preheat way of primary air, with the new ideas of primary air preheated by boiler feed water and the optimized air preheating way.%对垃圾焚烧发电厂一次风加热器Ⅱ段的加热介质采用锅炉出口过热蒸汽和汽包饱和蒸汽进行比较,结果表明:过热蒸汽抽汽较汽包饱和蒸汽抽汽的抽汽量减少20.8%,热量减少8.7%,并增加了进汽机的蒸汽量,同时预热器Ⅱ段换热面积可减少约20%,造价相应降低约10%.过热蒸汽加热有投资成本小、蒸汽耗量小、热量有效利用率高的优点.并通过锅炉给水预热一次风、优化的空气预热方式等新的一次风预热思路,供不同垃圾性质、焚烧规模、控制策略等选择一次风预热形式时参考.

  8. Ventilation filters as sources of air pollution – Processes occurring on surfaces of used filters

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Halás, Oto; Clausen, Geo

    2004-01-01

    Ozone concentrations were monitored upstream and downstream of used filter samples following 24hours of ventilation with ozone- filtered air. The ozone concentration in the air upstream of the filters was maintained at ~75 ppb while the concentration downstream of the filters was initially betwee...

  9. Measurement and Modelling of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Heiselberg, Per; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    Air flow rate in a naturally ventilated double skin façade (DSF) is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes the results of two different methods to measure the air flow in a full-scale ...

  10. Thermal environment and air quality in office with personalized ventilation combined with chilled ceiling

    DEFF Research Database (Denmark)

    Lipczynska, Aleksandra; Kaczmarczyk, Jan; Melikov, Arsen Krikor

    2015-01-01

    in thermal environment were found between studied systems. The room air mixing with PV working alone was at the same level as with mixing ventilation. No substantial differences in contaminants' concentration distribution and air-change effectiveness were found between the studied systems in the occupied...

  11. Room air stratification in combined chilled ceiling and displacement ventilation systems.

    OpenAIRE

    Schiavon, Stefano; Bauman, Fred; Tully, Brad; Rimmer, Julian

    2012-01-01

    Radiant chilled ceilings (CC) with displacement ventilation (DV) represent a promising integrated system design that combines the energy efficiency of both sub-systems with the opportunity for improved ventilation performance resulting from the thermally stratified environment of DV systems. The purpose of this study was to conduct laboratory experiments for a typical U.S. interior zone office to investigate how room air stratification is affected by the ratio of cooling load removed by a chi...

  12. Test Protocol for Room-to-Room Distribution of Outside Air by Residential Ventilation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Barley, C. D.; Anderson, R.; Hendron, B.; Hancock, E.

    2007-12-01

    This test and analysis protocol has been developed as a practical approach for measuring outside air distribution in homes. It has been used successfully in field tests and has led to significant insights on ventilation design issues. Performance advantages of more sophisticated ventilation systems over simpler, less-costly designs have been verified, and specific problems, such as airflow short-circuiting, have been identified.

  13. Solar assisted ventilation tower, Frederiksberg[Denmark]; Ventilationsanlaeggenes betydning for ejendommens varmeforbrug. Delrapport 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-04-01

    The project has demonstrated a building integrated ventilation system with the ducts system installed outside the facade. The air ducts are installed in a solar tower parallel to the staircases in the courtyard. The towers utilise the solar energy for preheating the ventilation air. An air handling unit with counterflow heat exchanger is installed in the roof space. The system is designed for old building block, which are going to be renovated with mechanical ventilation. The system saves room space for the installations of the ventilation ducts. The monitoring of the system performance shows energy saving of 40% caused by new windows, individual heat meters and ventilation with heat recovery and solar tower. The system efficiency of the solar tower is high compared with other traditional solar wall constructions. The ventilation system is designed with a very low electricity consumption of the fans. The monitored electricity consumption is 22 W per dwellings. (au)

  14. Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, Willliam JN [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    Changing the rate of airflow through a home affects the annual thermal conditioning energy. Large-scale changes to airflow rates of the housing stock can significantly alter the energy consumption of the residential energy sector. However, the complexity of existing residential energy models hampers the ability to estimate the impact of policy changes on a state or nationwide level. The Incremental Ventilation Energy (IVE) model developed in this study was designed to combine the output of simple airflow models and a limited set of home characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modelers to use existing databases of home characteristics to determine the impact of policy on ventilation at a population scale. In this report, we describe the IVE model and demonstrate that its estimates of energy change are comparable to the estimates of a wellvalidated, complex residential energy model when applied to homes with limited parameterization. Homes with extensive parameterization would be more accurately characterized by complex residential energy models. The demonstration included a range of home types, climates, and ventilation systems that cover a large fraction of the residential housing sector.

  15. Influence of the pre-ionization background and simulation of the optical emission of a streamer discharge in preheated air at atmospheric pressure between two point electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bourdon, A; Bonaventura, Z [Ecole Centrale Paris, EM2C Laboratory, UPR CNRS 288, Grande voie des vignes, 92295 Chatenay-Malabry Cedex (France); Celestin, S, E-mail: anne.bourdon@em2c.ecp.f [Communications and Space Sciences Laboratory, Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-06-15

    This paper presents simulations of positive and negative streamers propagating between two point electrodes in preheated air at atmospheric pressure. As many discharges have occurred before the simulated one, seed charges are taken into account in the interelectrode gap. First, for a pre-ionization background of 10{sup 9} cm{sup -3}, we have studied the influence of the data set used for transport parameters and reaction rates for air on the simulation results. We have compared results obtained in 1997 using input parameters from Morrow and Lowke and from Kulikovsky. Deviations as large as 20% of streamer characteristics (i.e. electric field in the streamer head and body, streamer velocity, streamer radius, streamer electron density) have been observed for this point-to-point configuration. Second, we have studied the influence of the pulsed voltage frequency on the discharge structure. For the studied discharge regime, a change in the applied voltage frequency corresponds to a change in the pre-ionization background. In this work, we have considered a wide range of pre-ionization values from 10{sup 4} and up to 10{sup 9} cm{sup -3}. We have noted that the value of the pre-ionization background has a small influence on the electron density, electric field and location of the negative streamer head. Conversely, it has a significant influence on the positive streamer characteristics. Finally, we have compared instantaneous and time-averaged optical emissions of the three band systems of N{sub 2} and N{sub 2}{sup +} (1PN{sub 2}, 2PN{sub 2} and 1NN{sub 2}{sup +}) during the discharge propagation. We have shown that the emission of the 2PN{sub 2} is the strongest of the three bands, in agreement with experimental observations. It is interesting to note that even with a short time averaging of a few nanoseconds, which corresponds to currently used instruments, the structure of the time-averaged emission of the 2PN{sub 2} is different from the instantaneous one and shows

  16. CLEAN-AIR heat pump. Reduced energy consumption for ventilation in buildings by integrating air cleaning and heat pump. Final Report; CLEAN-AIR heat pump - Reduceret energiforbrug til ventilation af bygninger ved luftrensning integreret med luft varmepumpe. Slut rapport

    Energy Technology Data Exchange (ETDEWEB)

    Fang, L.; Olesen, Bjarne W.; Molinaro, G.; Simmonsen, P.; Skocajic, S. [Danmarks Tekniske Univ. Institut for Byggeri og Anlaeg, Lyngby (Denmark); Hummelshoej, R.M.; Carlassara, L. [COWI A/S, Lyngby, (Denmark); Groenbaek, H.; Hansen, Ole R. [Exhausto A/S, Langeskov (Denmark)

    2011-07-01

    This report summarizes task 1 of the Clean Air Heat Pump project - modelling and simulation on energy savings when using the clean air heat pump for ventilation, air cleaning and energy recovery. The total energy consumption of the proposed ventilation systems using clean air heat pump technology was calculated by a theoretical model and compared with the reference ventilation systems (conventional ventilation systems). The energy compared between the two systems includes energy used for heating, cooling and fan. The simulation and energy saving calculation was made for the application of the clean air heat pump in three typical climate conditions, i.e. mild-cold, mild-hot and hot and wet climates. Real climate data recorded from three cities in 2002 was used for the calculation. The three cities were Copenhagen (Denmark), Milan (Italy) and Colombo (Sir Lanka) which represent the above three typical climate zones. For the Danish climate (the mild cold climate), the calculations show that the ventilation system using clean air heat pump technology can save up to 42% of energy cost in winter compared to the conventional ventilation system. The energy saving in summer can be as high as 66% for the ventilation system with humidity control and 9% for the ventilation system without the requirement of humidity control. Since the Danish summer climate is very mild, over 80% of the yearly energy consumption for ventilation is used during winter season. It is, therefore, estimated that more than 35% annual energy saving for ventilation is expected in Denmark using the clean air heat pump ventilation technology. For the mild hot climate, e.g. the Italian climate, the calculations show that up to 63% of the energy saving can be achieved in summer season. For the winter mode, 17% reduction of the energy cost can be expected for the domestic use. For industrial use, the energy cost of the clean air heat pump may not be favourable due to the industrial price of gas in Italy is

  17. 回转式空气预热器漏风问题的分析与对策%Analysis and Measures for Air Leakage of Rotary Air Preheater

    Institute of Scientific and Technical Information of China (English)

    夏志强; 朱新源

    2009-01-01

    大型电站锅炉广泛采用回转式空气预热器作为尾部换热设备.但是,漏风率过高是各电厂为提高经济效益需要解决的问题.通过分析分析影响漏风的因素,提出了采用双密封,安装漏风自动控制系统等降低漏风的对策.%The rotary preheater is one of the most important heat-exchange equipments in some large-sized thermal power plants. High air leakage rate, which will do much harm to the power plant, is one stubborn problem that needs to be solved to improve economic benefits. The factors influencing air leakage are analyzed, and it is suggested to adopt double seal, install air leakage automatic control system to reduce the air leakage.

  18. A ventilation intervention study in classrooms to improve indoor air quality: the FRESH study.

    Science.gov (United States)

    Rosbach, Jeannette T M; Vonk, Machiel; Duijm, Frans; van Ginkel, Jan T; Gehring, Ulrike; Brunekreef, Bert

    2013-12-17

    Classroom ventilation rates often do not meet building standards, although it is considered to be important to improve indoor air quality. Poor indoor air quality is thought to influence both children's health and performance. Poor ventilation in The Netherlands most often occurs in the heating season. To improve classroom ventilation a tailor made mechanical ventilation device was developed to improve outdoor air supply. This paper studies the effect of this intervention. The FRESH study (Forced-ventilation Related Environmental School Health) was designed to investigate the effect of a CO2 controlled mechanical ventilation intervention on classroom CO2 levels using a longitudinal cross-over design. Target CO2 concentrations were 800 and 1200 parts per million (ppm), respectively. The study included 18 classrooms from 17 schools from the north-eastern part of The Netherlands, 12 experimental classrooms and 6 control classrooms. Data on indoor levels of CO2, temperature and relative humidity were collected during three consecutive weeks per school during the heating seasons of 2010-2012. Associations between the intervention and weekly average indoor CO2 levels, classroom temperature and relative humidity were assessed by means of mixed models with random school-effects. At baseline, mean CO2 concentration for all schools was 1335 ppm (range: 763-2000 ppm). The intervention was able to significantly decrease CO2 levels in the intervention classrooms (F (2,10) = 17.59, p < 0.001), with a mean decrease of 491 ppm. With the target set at 800 ppm, mean CO2 was 841 ppm (range: 743-925 ppm); with the target set at 1200 ppm, mean CO2 was 975 ppm (range: 887-1077 ppm). Although the device was not capable of precisely achieving the two predefined levels of CO2, our study showed that classroom CO2 levels can be reduced by intervening on classroom ventilation using a CO2 controlled mechanical ventilation system.

  19. Numerical Analysis on Ventilating and Air Conditioning Scheme of Shenyang Subway Station

    Institute of Scientific and Technical Information of China (English)

    LI Wei; NA Yanling

    2007-01-01

    Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.

  20. Cerebral Arterial Air Embolism Associated with Mechanical Ventilation and Deep Tracheal Aspiration

    Directory of Open Access Journals (Sweden)

    S. Gursoy

    2012-01-01

    Full Text Available Arterial air embolism associated with pulmonary barotrauma has been considered a rare but a well-known complication of mechanical ventilation. A 65-year-old man, who had subarachnoid hemorrhage with Glasgow coma scale of 8, was admitted to intensive care unit and ventilated with the help of mechanical ventilator. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS decreased from 8–10 to 4-5, and the patient was reevaluated with cranial CT scan. In CT scan, air embolism was detected in the cerebral arteries. The patient deteriorated and spontaneous respiratory activity lost just after the CT investigation. Thirty minutes later cardiac arrest appeared. Despite the resuscitation, the patient died. We suggest that pneumonia and frequent tracheal aspirations are predisposing factors for cerebral vascular air embolism.

  1. Indoor Air Quality and Ventilation Strategies in the Use of Combustion Space Heating Appliances in Housing

    OpenAIRE

    Setiani, Onny

    1994-01-01

    Indoor air quality (IAQ) in the use of combustion appliances is important for adequate evaluation of air pollution health risks. Since people spend most of their time inside buildings, especially the elderly and children, their exposure to indoor air contaminants can increase health problems in the community. Combustion materials emitted from combustion space heating appliances in housing during the winter may become a serious problem to health, since sources of ventilation are usually left c...

  2. Symptoms and perceived indoor air quality among occupants of houses and apartments with different ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Ruotsalainen, R.; Roennberg, R.; Majanen, A.; Seppaenen, O. (Laboratory of Heating, Ventilating and Air Conditioning, Helsinki University of Technology, Espoo (Finland)); Jaakkola, J.J.K. (Laboratory of Heating, Ventilating and Air Conditioning, Helsinki University of Technology, Espoo (Finland) Department of Public Health, University of Helsinki (Finland))

    1991-01-01

    The purpose of the study was to evaluate the occurrence of symptoms and the perception of poor indoor air quality among the occupants of houses and apartments with different ventilation systems. The study population consisted of the 473 occupants of 242 dwellings in the Helsinki metropolitan area who responded to a self-administered questionnaire (response rate 93.1%) after a two-week period of indoor air quality measurements. The symptoms of interest were those often related to poor indoor air quality including dryness or itching of the skin; dryness, irritation or itching of the eyes; nasal congestion (''blocked nose''); nasal dryness; nasal discharge (''runny nose''); sneezing; cough; breathlessness; headache or migraine; and lethargy, weakness or nausea. Perception of coldness; warmness; draught; dryness; stuffiness; and sufficiency of air exchange was also requested. The age-standardized period prevalences of the symptoms and complaints were systematically more common among the occupants of the apartments than those of the houses. The occupants of the houses with natural ventilation seemed to have more symptoms and complaints than those with balanced ventilation. However, in the apartments with blanced ventilation the occupants reported, in general, more symptoms and complaints than those with natural ventilation. (au) (9 refs.).

  3. [Assessment of the air quality improment of cleaning and disinfection on central air-conditioning ventilation system].

    Science.gov (United States)

    Liu, Hongliang; Zhang, Lei; Feng, Lihong; Wang, Fei; Xue, Zhiming

    2009-09-01

    To assess the effect of air quality of cleaning and disinfection on central air-conditioning ventilation systems. 102 air-conditioning ventilation systems in 46 public facilities were sampled and investigated based on Hygienic assessment criterion of cleaning and disinfection of public central air-conditioning systems. Median dust volume decreased from 41.8 g/m2 to 0.4 g/m2, and the percentage of pipes meeting the national standard for dust decreased from 17.3% (13/60) to 100% (62/62). In the dust, median aerobic bacterial count decreased from 14 cfu/cm2 to 1 cfu/cm2. Median aerobic fungus count decreased from 10 cfu/cm2 to 0 cfu/cm2. The percentage of pipes with bacterial and fungus counts meeting the national standard increased from 92.4% (171/185) and 82.2% (152/185) to 99.4% (165/166) and 100% (166/166), respectively. In the ventilation air, median aerobic bacterial count decreased from 756 cfu/m3 to 229 cfu/m3. Median aerobic fungus count decreased from 382 cfu/m3 to 120 cfu/m3. The percentage of pipes meeting the national standard for ventilation air increased from 33.3% (81/243) and 62.1% (151/243) to 79.8% (292/366) and 87.7% (242/276), respectively. But PM10 rose from 0.060 mg/m3 to 0.068 mg/m3, and the percentage of pipes meeting the national standard for PM10 increased from 74.2% (13/60) to 90.2% (46/51). The cleaning and disinfection of central air-conditioning ventilation systems could have a beneficial effect of air quality.

  4. Indoor air pollutants, ventilation rate determinants and potential control strategies in Chinese dwellings: A literature review.

    Science.gov (United States)

    Ye, Wei; Zhang, Xu; Gao, Jun; Cao, Guangyu; Zhou, Xiang; Su, Xing

    2017-05-15

    After nearly twenty years of rapid modernization and urbanization in China, huge achievements have transformed the daily lives of the Chinese people. However, unprecedented environmental consequences in both indoor and outdoor environments have accompanied this progress and have triggered public awareness and demands for improved living standards, especially in residential environments. Indoor pollution data measured for >7000 dwellings (approximately 1/3 were newly decorated and were tested for volatile organic compound (VOC) measurements, while the rest were tested for particles, phthalates and other semi-volatile organic compounds (SVOCs), moisture/mold, inorganic gases and radon) in China within the last ten years were reviewed, summarized and compared with indoor concentration recommendations based on sensory or health end-points. Ubiquitous pollutants that exceed the concentration recommendations, including particulate matter, formaldehyde, benzene and other VOCs, moisture/mold, inorganic gases and radon, were found, indicating a common indoor air quality (IAQ) issue in Chinese dwellings. With very little prevention, oral, inhalation and dermal exposure to those pollutants at unhealthy concentration levels is almost inevitable. CO2, VOCs, humidity and radon can serve as ventilation determinants, each with different ventilation demands and strategies, at typical occupant densities in China; and particle reduction should be a prerequisite for determining ventilation requirements. Two directional ventilation modes would have profound impacts on improving IAQ for Chinese residences are: 1) natural (or window) ventilation with an air cleaner and 2) mechanical ventilation with an air filtration unit, these two modes were reviewed and compared for their applicability and advantages and disadvantages for reducing human exposure to indoor air pollutants. In general, mode 2 can more reliably ensure good IAQ for occupants; while mode 1 is more applicable due to its low

  5. CFD model of air movement in ventilated façade: comparison between natural and forced air flow

    Directory of Open Access Journals (Sweden)

    Miguel Mora Pérez, Gonzalo López Patiño, P. Amparo López Jiménez

    2013-01-01

    Full Text Available This study describes computational fluid dynamics (CFD modeling of ventilated façade. Ventilated façades are normal façade but it has an extra channel between the concrete wall and the (double skin façade. Several studies found in the literature are carried out with CFD simulations about the behavior of the thermodynamic phenomena of the double skin façades systems. These studies conclude that the presence of the air gap in the ventilated façade affects the temperature in the building skin, causing a cooling effect, at least in low-rise buildings. One of the most important factors affecting the thermal effects of ventilated façades is the wind velocity. In this contribution, a CFD analysis applied on two different velocity assumptions for air movement in the air gap of a ventilated façade is presented. A comparison is proposed considering natural wind induced velocity with forced fan induced velocity in the gap. Finally, comparing temperatures in the building skin, the differences between both solutions are described determining that, related to the considered boundary conditions, there is a maximum height in which the thermal effect of the induced flow is significantly observed.

  6. The Effect of Ventilation, Filtration and Passive Sorption on Indoor Air Quality in Museum Storage Rooms

    DEFF Research Database (Denmark)

    Ryhl-Svendsen, M.; Clausen, Geo

    2009-01-01

    A study was conducted in five storage rooms at the National Museum of Denmark, in which the effect on indoor air quality of mechanical ventilation, filtration and passive sorption was investigated. Mechanical ventilation and recirculation/filtration was initiated by introducing new ventilation...... and filtration units. Passive sorption was initiated by hanging sheets of sorptive materials oil walls. The control strategies were evaluated in terms of their ability to lower the concentration of internally, generated pollutants, and the indoor-to-outdoor concentration ratio of outdoor pollutants. The overall...... environmental impact for each method was evaluated by the use of material dosimeters. It was found that passive sorption performed better in a small room compared to a large room. Mechanical ventilation and filtration with activated charcoal gave a high protection against ozone, but were less effective...

  7. Ventilation of indoor formaldehyde and estimation of its emission and air exchange rate

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; ZHAO Qing-liang; LI Wen-pu; LI Yu-hua

    2007-01-01

    Residents living in the cold areas such as Harbin generally experience a residence time of approximately 6 months in chilly winter without frequent natural ventilation. To find out the influence of a short period of ventilation on the indoor formaldehyde concentration inside a new building, an investigation was conducted for the instance of twice ventilation in a day through window opening. The results showed that the initial concentration of formaldehyde was 3.53 - 8.48 times as high as the concentration after 10 min ventilation. After closing the window, the indoor formaldehyde concentration increased with time and followed an exponential equation of C = C0exp( - b * t) + (a + Cw) [ 1 - exp( - b * t) ] with correlation coefficient (R2) of 0. 945 -0. 999, based on the statistical analysis of 14 groups of measurement data. The developed equation can be used to estimate the emission rate of indoor formaldehyde sources and the air exchange rate of the test room simultaneously.

  8. Velocity Distribution in a Room Ventilated by Displacement Ventilation and Wall-Mounted Air Terminal Devices

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    2000-01-01

    The article describes experiments with wall-mounted air terminal devices. The airflow from an air terminal device influences the occupants' thermal comfort and, therefore, it is important to develop an expression for this flow in the occupied zone. The velocity at the floor is influenced by the f...

  9. Air quality Performance of Ductless Personalized Ventilation in Conjunction with Displacement Ventilation: Impact of Walking Person

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Lu, Pengfei; Melikov, Arsen Krikor

    2015-01-01

    in inhaled air by the two manikins were measured. The DPV was not able to protect the exposed person from contaminants emitted from a sitting and polluting occupant when there were disturbances close to the DPV. However, using the DPV at the polluting manikin’s workstation resulted in better inhaled air...

  10. The effects of reduced ventilation on indoor air quality in an office building

    Science.gov (United States)

    Turiel, I.; Hollowell, C. D.; Miksch, R. R.; Rudy, J. V.; Young, R. A.; Coye, M. J.

    Indoor air quality was monitored at an office building in San Francisco, CA where occupants had registered eye, nose and throat irritation complaints. Portable air pollution monitoring equipment was placed on site to monitor air outdoors and at three indoor sites (a waiting room, an interview room and an office room), and data were taken under two different ventilation rates. The parameters measured were outside air flow rates, temperature, relative humidity, odor perception, microbial burden, particulate mass, formaldehyde and other organics, carbon dioxide, carbon monoxide and nitrogen dioxide. Carbon dioxide concentrations increased as the ventilation rate decreased; odor perceptibility increased slightly at the lowest ventilation rate, and other pollutants generally showed very low concentrations, which increased when ventilation was reduced. In no case, however, did levels exceed current health standards for outdoor air, nor was any one contaminant found to be responsible for the medical symptoms reported by occupants. It is possible that a synergistic effect of the various contaminants and environmental conditions may account for the discomfort of occupants.

  11. Air renewal times and ventilation rate calculations for underground workings using radioactive measurement

    Institute of Scientific and Technical Information of China (English)

    Ayman A. El-Abnoudy⇑; Sayed F. Hassan

    2016-01-01

    Potential alpha emitters are of prime concern to the ventilation engineer due to their rapid concentration increasing once radon released in the mine atmosphere, causing tissue irradiation and lung cancer. Studying of the time based variations of the natural ventilation in tunnels and their relationship to the external parameters contribute to the air circulation assessment. Due to the continuous and high fluctu-ation of the meteorological conditions affecting the air circulation and intensity through the underground workings, there is a difficulty in the natural ventilation assessment by only the ordinary meteorological measurements. So, in this paper, the possibility of using the radioactive measurements, allowing for the air aging and ventilation quality to be qualified, is investigated through three different underground structures. Referring to the most confined structure of them, results show that one structure has a better exchange rate by a factor 1.8 and the other has the best rate by a factor 2.1. This parameter can be linked to the operating costs and size of a future ventilation system.

  12. Assessment of Indoor Air Quality Benefits and Energy Costs of Mechanical Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Logue, J.M.; Price, P.N.; Sherman, M.H.; Singer, B.C.

    2011-07-01

    Intake of chemical air pollutants in residences represents an important and substantial health hazard. Sealing homes to reduce air infiltration can save space conditioning energy, but can also increase indoor pollutant concentrations. Mechanical ventilation ensures a minimum amount of outdoor airflow that helps reduce concentrations of indoor emitted pollutants while requiring some energy for fan(s) and thermal conditioning of the added airflow. This work demonstrates a physics based, data driven modeling framework for comparing the costs and benefits of whole-house mechanical ventilation and applied the framework to new California homes. The results indicate that, on a population basis, the health benefits from reduced exposure to indoor pollutants in New California homes are worth the energy costs of adding mechanical ventilation as specified by ASHRAE Standard 62.2.This study determines the health burden for a subset of pollutants in indoor air and the costs and benefits of ASHRAE's mechanical ventilation standard (62.2) for new California homes. Results indicate that, on a population basis, the health benefits of new home mechanical ventilation justify the energy costs.

  13. Should Title 24 Ventilation Requirements Be Amended to include an Indoor Air Quality Procedure?

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Spencer M.; Mendell, Mark J.; Chan, Wanyu R.

    2013-05-13

    Minimum outdoor air ventilation rates (VRs) for buildings are specified in standards, including California?s Title 24 standards. The ASHRAE ventilation standard includes two options for mechanically-ventilated buildings ? a prescriptive ventilation rate procedure (VRP) that specifies minimum VRs that vary among occupancy classes, and a performance-based indoor air quality procedure (IAQP) that may result in lower VRs than the VRP, with associated energy savings, if IAQ meeting specified criteria can be demonstrated. The California Energy Commission has been considering the addition of an IAQP to the Title 24 standards. This paper, based on a review of prior data and new analyses of the IAQP, evaluates four future options for Title 24: no IAQP; adding an alternate VRP, adding an equivalent indoor air quality procedure (EIAQP), and adding an improved ASHRAE-like IAQP. Criteria were established for selecting among options, and feedback was obtained in a workshop of stakeholders. Based on this review, the addition of an alternate VRP is recommended. This procedure would allow lower minimum VRs if a specified set of actions were taken to maintain acceptable IAQ. An alternate VRP could also be a valuable supplement to ASHRAE?s ventilation standard.

  14. Performance of personalized ventilation in a room with an underfloor air distribution system: transport of contaminants between occupants

    DEFF Research Database (Denmark)

    Cermak, Radim; Melikov, Arsen Krikor

    2003-01-01

    Studies have documented that personalized ventilation, which provides clean air at each office workplace, is able to improve substantially the quality of air inhaled by occupants. However, the interaction between the airflow generated by personalized ventilation and the airflow pattern outside th...

  15. Environmental Technology Verification: Supplement to Test/QA Plan for Biological and Aerosol Testing of General Ventilation Air Cleaners; Bioaerosol Inactivation Efficiency by HVAC In-Duct Ultraviolet Light Air Cleaners

    Science.gov (United States)

    The Air Pollution Control Technology Verification Center has selected general ventilation air cleaners as a technology area. The Generic Verification Protocol for Biological and Aerosol Testing of General Ventilation Air Cleaners is on the Environmental Technology Verification we...

  16. Preheating with fractional powers

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-11-01

    We consider preheating in models in which the potential for the inflaton is given by a fractional power, as is the case in axion monodromy inflation. We assume a standard coupling between the inflaton field and a scalar matter field. We find that in spite of the fact that the oscillation of the inflaton about the field value which minimizes the potential is anharmonic, there is nevertheless a parametric resonance instability, and we determine the Floquet exponent which describes this instability as a function of the parameters of the inflaton potential.

  17. The Histoty of Ventilation and Air Conditioning is CERN Up to Date with the latest Technological Developments?

    CERN Document Server

    Kühnl-Kinel, J

    2000-01-01

    The invention of ventilation cannot be ascribed to a certain date. It started with simple aeration when man brought fire into his abode and continued through different stages including air cooling using ice to finally arrive at the time when ventilation and air conditioning has become an essential part of our life and plays an important role in human evolution. This paper presents the history of ventilation and air conditioning, explains the key constraints over the centuries, and shows its influence on everyday life. Some examples of previous air-conditioning plants are described and different approaches to the way of calculation of ventilation systems discussed. It gives an overview of the Heating, Ventilation and Air Conditioning (HVAC) installations at CERN and points out their particularities. It also compares them with the latest technological developments in the field as well as showing the new trends that are being applied at CERN.

  18. Optimizing of Make Up Air Performance for Commercial Kitchen Ventilation Improvement

    Directory of Open Access Journals (Sweden)

    Manshoor B.

    2014-07-01

    Full Text Available A commercial kitchen is a complicated environment where multiple components of a ventilation system including kitchen hood, exhaust fan, air supply, and make up air systems work together but not always in unison. For the commercial kitchen environment, make up air systems used to control the kitchen space from unwanted odor and thermal confort. Make air systems for commercial kitchen already established. However, an optimization is important to determine the most suitable make air systems and at the same time can improve the thermal comfort in the working space. In this study, a simulation work was conducted to investigate a suitable supply air velocity to optimize the make up air for kitchen ventilation system. In order to achieve the objectives, ANSYS FLUENT software (CFD was used to carry out the simulation and analysis. 3D kitchen space with 10m x 8m x 3m with air supply velocity was set to 0 m/s, 0.14 m/s, 0.28 m/s and 0.42 m/s. From the simulation work, the velocity of air flow tested which is 0.28 m/s is enough to control the heat and give an enough comfort to the working space for the size of kitchen simulated. Well implementation of the make up air in the kitchen hood can improve an air quality in the commercial kitchen and also keep the kitchen space comfortable to the workers.

  19. Air quality in low-ventilated museum storage buildings

    DEFF Research Database (Denmark)

    Ryhl-Svendsen, Morten; Aasbjerg Jensen, Lars; Klenz Larsen, Poul

    2014-01-01

    Modern low-energy museum storage buildings are often designed for a low air exchange rate, on the order of less than 1 exchange per day. We investigated how this affected the indoor air quality in six Danish museum storage buildings. The infiltration of ambient pollutants, and the level to which...... internally-generated pollutants accumulate, were measured by passive sampling of ozone, nitrogen dioxide, and organic acids. The air exchange rates and the interchange of air between storage rooms were measured by the per-fluorocarbon tracer gas method. Ambient pollutants were reduced in concentration...

  20. Air quality in low-ventilated museum storage buildings

    DEFF Research Database (Denmark)

    Ryhl-Svendsen, Morten; Aasbjerg Jensen, Lars; Klenz Larsen, Poul

    2014-01-01

    Modern low-energy museum storage buildings are often designed for a low air exchange rate, on the order of less than 1 exchange per day. We investigated how this affected the indoor air quality in six Danish museum storage buildings. The infiltration of ambient pollutants, and the level to which...... internally-generated pollutants accumulate, were measured by passive sampling of ozone, nitrogen dioxide, and organic acids. The air exchange rates and the interchange of air between storage rooms were measured by the per-fluorocarbon tracer gas method. Ambient pollutants were reduced in concentration...

  1. Measurement of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Jensen, Rasmus Lund; Heiselberg, Per

    2007-01-01

    Air flow rate in a naturally ventilated space is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes three different methods to measure the air flow in a full-scale outdoor test facility...... with a naturally ventilated double skin façade. In the first method, the air flow in the cavity is estimated on the basis of six measured velocity profiles. The second method is represented by constant injection of tracer gas and in the third method a measured relation in the laboratory is used to estimate...... the flow rate on the basis of continues measurement of the pressure difference between the surface pressure at the opening and inside pressure of the double skin façade. Although all three measurement methods are difficult to use under such dynamic air flow conditions, two of them show reasonable agreement...

  2. Ventilation behaviour and indoor air problems in different types of newly built dwellings

    NARCIS (Netherlands)

    Dongen, J.E.F. van; Phaff, J.C.

    1989-01-01

    In four types of newly built single family dwellings and in apartments of a block of flats in the Netherlands, the behaviour and motivations of the occupants are studied with respect to their response to heating and ventilation, as well as their judgment on indoor air and climate variables such as t

  3. Occupant Time Period of Thermal Adaption to Change of Outdoor Air Temperature in Naturally Ventilated Buildings

    DEFF Research Database (Denmark)

    liu, weiwei; Wargocki, Pawel; Xiong, Jing

    2014-01-01

    The present work proposed a method to determine time period of thermal adaption of occupants in naturally ventilated building, based on the relationship between their neutral temperatures and running mean outdoor air temperature. Based on the data of the field investigation, the subjects’ time...

  4. Ventilation behaviour and indoor air problems in different types of newly built dwellings

    NARCIS (Netherlands)

    Dongen, J.E.F. van; Phaff, J.C.

    1989-01-01

    In four types of newly built single family dwellings and in apartments of a block of flats in the Netherlands, the behaviour and motivations of the occupants are studied with respect to their response to heating and ventilation, as well as their judgment on indoor air and climate variables such as

  5. A Technical Basis for Employing Facility Ventilation Air Exchange Rates in the Decision to Downpost

    CERN Document Server

    Mantooth, D S

    2001-01-01

    Utilizing the ventilation exchange rate as a basis for the decision to downpost a location within a facility from an airborne radiation area (ARA) based on initial air count(DAC). Not used in the case of a confirmed or suspected contamination release.

  6. Measurement of the Air Chance Rate and Ventilation Characteristics During Short Term Transient Phenomena

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Perino, M.

    2004-01-01

    is assured throughout the test. However, due to the relatively slow response of the gas analysers, none of these procedures can usually be applied to fast transient phenomena that last 15 minutes or less. Moreover in many cases of natural ventilation strategies, the continuous mixing of the indoor air would...

  7. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Introduction to Construction Series. Instructor Edition.

    Science.gov (United States)

    Associated General Contractors of America, Washington, DC.

    This module on introductory heating, ventilating, and air conditioning (HVAC) is one of a series of modules designed to teach basic skills necessary for entry-level employment in this field. The module contains four instructional units that cover the following topics: (1) HVAC materials; (2) HVAC tools; (3) HVAC layout; and (4) HVAC basic skills.…

  8. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Instructor Edition. Introduction to Construction Series.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructor's guide contains the materials required to teach a competency-based introductory course in heating, ventilating, and air conditioning (HVAC) to students who have chosen to explore careers in construction. It contains three units: HVAC materials, HVAC tools, and applied skills. Each instructional unit includes some or all of the…

  9. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Instructor Edition. Introduction to Construction Series.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructor's guide contains the materials required to teach a competency-based introductory course in heating, ventilating, and air conditioning (HVAC) to students who have chosen to explore careers in construction. It contains three units: HVAC materials, HVAC tools, and applied skills. Each instructional unit includes some or all of the…

  10. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Introduction to Construction Series. Instructor Edition.

    Science.gov (United States)

    Associated General Contractors of America, Washington, DC.

    This module on introductory heating, ventilating, and air conditioning (HVAC) is one of a series of modules designed to teach basic skills necessary for entry-level employment in this field. The module contains four instructional units that cover the following topics: (1) HVAC materials; (2) HVAC tools; (3) HVAC layout; and (4) HVAC basic skills.…

  11. Measurement and Numerical Simulation of Air Velocity in a Tunnel-Ventilated Broiler House

    Directory of Open Access Journals (Sweden)

    Eliseo Bustamante

    2015-02-01

    Full Text Available A building needs to be designed for the whole period of its useful life according to its requirements. However, future climate predictions involve some uncertainty. Thus, several sustainable strategies of adaptation need to be incorporated after the initial design. In this sense, tunnel ventilation in broiler houses provides high air velocity values (2–3 m·s−1 at animal level to diminish their thermal stress and associated mortality. This ventilation system was experimentally incorporated into a Mediterranean climate. The aim was to resolve these thermal problems in hot seasons, as (traditional cross-mechanical ventilation does not provide enough air velocity values. Surprisingly, very little information on tunnel ventilation systems is available, especially in terms of air velocity. Using Computational Fluid Dynamics (CFD and a multi-sensor system, the average results are similar (at animal level: 1.59 ± 0.68 m·s−1 for CFD and 1.55 ± 0.66 m·s−1 for measurements. The ANOVA for validation concluded that the use of CFD or measurements is not significant (p-value = 0.1155. Nevertheless, some problems with air velocity distribution were found and need to be solved. To this end, CFD techniques can help by means of virtual designs and scenarios providing information for the whole indoor space.

  12. Airflow adjustment and minimization of the air power of ventilation network

    Institute of Scientific and Technical Information of China (English)

    INOUE Masahiro; YANG Wen-yu

    2011-01-01

    It is often required to know which roadway (adjustment roadway) resistances and how much values of the resistances should be changed to make the airflow rates in roadways (target roadways) to certain required values in the practice of mine ventilation.In this case,the airflow rates of the target roadways and the resistances of the roadways other than the adjustment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found.No straightforward method to solve the problem has been found up to now.Therefore,trial and error method using the ventilation network analysis program is utilized to solve the problem so far.The method takes long calculation time and the best answer is not necessarily obtained.The authors newly defmed "airflow element" as an element of the ventilation network analysis.The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis.The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method.The authors made the computer program fulfill the method.The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.

  13. Effectiveness of horizontal air flow fans supporting natural ventilation in a Mediterranean multi-span greenhouse

    Directory of Open Access Journals (Sweden)

    Alejandro López

    2013-08-01

    Full Text Available Natural ventilation is the most important method of climate control in Mediterranean greenhouses. In this study, the microclimate and air flow inside a Mediterranean greenhouse were evaluated by means of sonic anemometry. Experiments were carried out in conditions of moderate wind (≈ 4.0 m s-1, and at low wind speed (≈ 1.8 m s-1 the natural ventilation of the greenhouse was supplemented by two horizontal air flow fans. The greenhouse is equipped with a single roof vent opening to the windward side and two side vents, the windward one being blocked by another greenhouse close to it, while the leeward one is free of obstacles. When no fans are used, air enters through the roof vent and exits through both side vents, thus flowing contrary to the thermal effect which causes hot air to rise and impairing the natural ventilation of the greenhouse. Using fans inside the greenhouse helps the air to circulate and mix, giving rise to a more homogeneous inside temperature and increasing the average value of normalized air velocity by 365 %. These fans also increase the average values of kinetic turbulence energy inside the greenhouse by 550 % compared to conditions of natural ventilation. As the fans are placed 4 m away from the side vents, their effect on the entrance of outside air is insufficient and they do not help to reduce the inside temperature on hot days with little wind. It is therefore recommended to place the fans closer to the side vents to allow an additional increase of the air exchange rate of greenhouses.

  14. Effects of supply air temperature and inlet location on particle dispersion in displacement ventilation rooms

    Institute of Scientific and Technical Information of China (English)

    Yanming Kang; Youjun Wang; Ke Zhong

    2011-01-01

    The effects of supply temperature and vertical location of inlet air on particle dispersion in a displacement ventilated (DV) room were numerically modeled with validation by experimental data from the literature.The results indicate that the temperature and vertical location of inlet supply air did not greatly affect the air distribution in the upper parts of a DV room,but could significantly influence the airflow pattern in the lower parts of the room,thus affecting the indoor air quality with contaminant sources located at the lower level,such as particles from working activities in an office.The numerical results also show that the inlet location would slightly influence the relative ventilation efficiency for the same air supply volume,but particle concentration in the breathing zone would be slightly lower with a low horizontal wall slot than a rectangular diffuser.Comparison of the results for two different supply temperatures in a DV room shows that,although lower supply temperature means less incoming air volume,since the indoor flow is mainly driven by buoyancy,lower supply temperature air could more efficiently remove passive sources (such as particles released from work activities in an office).However,in the breathing zone it gives higher concentration as compared to higher supply air temperature.To obtain good indoor air quality,low supply air temperature should be avoided because concentration in the breathing zone has a stronger and more direct impact on human health.

  15. INFLUENCE OF APPLYING ADDITIONAL FORCING FANS FOR THE AIR DISTRIBUTION IN VENTILATION NETWORK

    Directory of Open Access Journals (Sweden)

    Nikodem SZLĄZAK

    2016-07-01

    Full Text Available Mining progress in underground mines cause the ongoing movement of working areas. Consequently, it becomes neces-sary to adapt the ventilation network of a mine to direct airflow into newly-opened districts. For economic reasons, opening new fields is often achieved via underground workings. Length of primary intake and return routes increases and also increases the total resistance of a complex ventilation network. The development of a subsurface structure can make it necessary to change the air distribution in a ventilation network. Increasing airflow into newly-opened districts is necessary. In mines where extraction does not entail gas-related hazards, there is possibility of implementing a push-pull ventilation system in order to supplement airflows to newly developed mining fields. This is achieved by installing sub-surface fan stations with forcing fans at the bottom of downcast shaft. In push-pull systems with multiple main fans, it is vital to select forcing fans with characteristic curves matching those of the existing exhaust fans to prevent undesirable mutual interaction. In complex ventilation networks it is necessary to calculate distribution of airflow (especially in net-works with a large number of installed fans. In the article the influence of applying additional forcing fans for the air distribution in ventilation network for underground mine were considered. There are also analysed the extent of over-pressure caused by the additional forcing fan in branches of the ventilation network (the operating range of additional forcing fan. Possibilities of increasing airflow rate in working areas were conducted.

  16. Thermal sensation and comfort with five different air terminal devices for personalized ventilation

    DEFF Research Database (Denmark)

    Kaczmarczyk, Jan; Melikov, Arsen Krikor; Bolashikov, Z.

    constant at 23°C and relative humidity at 30%. A total supply of 90 L/s outdoor air was maintained with PVS and mixing ventilation or only with mixing ventilation. Air quality in the low-polluting office space was decreased by a 20-year-old used carpet that was placed behind a screen, so that subjects...... and the PVS. Six desks, each equipped with a PVS, were placed in the office. The PVS allowed each occupant to select his/her preferred position of the air terminal device (ATD), the direction of the air supplied and its flow rate (up to 15 L/s.person). The airflow rate from each PVS was measured and recorded...... for the whole duration of the experiment. The positioning of the ATD was registered as well. Subjects were exposed to four experimental conditions: PVS supplying outdoor air at: (1) 20°C; (2) 23°C; (3) PVS supplying re-circulated room air; and (4) mixing ventilation, without PVS. The room temperature was kept...

  17. Optimization of Ventilation Energy Demands and Indoor Air Quality in the ZEBRAlliance Homes

    Energy Technology Data Exchange (ETDEWEB)

    Hun, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2013-09-01

    High-performance homes require that ventilation energy demands and indoor air quality (IAQ) be simultaneously optimized. In this project, Oak Ridge National Laboratory researchers attempted to bridge these two areas by conducting tests in research houses located in Oak Ridge, TN, that were less than 2 years old, energy-efficient (i.e., expected to consume 50% less energy than a house built per the 2006 IRC), tightly-built, unoccupied, and unfurnished. The team identified air pollutants of concern in the test homes that could generally serve as indicators of IAQ, and conduced field experiments and computer simulations to determine the effectiveness and energy required by various techniques that lessened the concentration of these contaminants. Formaldehyde was selected as the main pollutant of concern from initial air sampling surveys. Field data indicate that concentrations were higher during the summer primarily because emissions from sources rise with increases in temperature. Furthermore, supply ventilation and gas-phase filtration were effective means to reduce formaldehyde concentrations; however, exhaust ventilation had minimal influence on this pollutant. Results from simulations suggest that formaldehyde concentrations obtained while ventilating per ASHRAE 62.2-2010 could be decreased by about 20% from May through September through three strategies: 1) increasing ASHRAE supply ventilation by a factor of two, 2) reducing the thermostat setpoint from 76 to 74°F, or 3) running a gas-phase filtration system while decreasing supply ventilation per ASHRAE by half. In the mixed-humid climate of Oak Ridge, these strategies caused minimal to modest increases in electricity cost of ~$5 to ~$15/month depending on outdoor conditions.

  18. 空气预热器烟气入口增设非平衡换热器的可行性分析%Feasibility of adding non-balance heat exchanger at gas inlet of air preheater

    Institute of Scientific and Technical Information of China (English)

    王春昌

    2014-01-01

    Against the rotating characteristics,low temperature corrosion ash deposition perform-ance and outlet gas temperature distribution rule of the rotary air preheater,it suggests non-bal-ance heat exchanger be added at the air preheater inlet and the flue duct be divided into several small ones.By properly reducing the inlet gas temperature of each small flue duct,the boiler ex-haust temperature becomes equilibrium and decreases on a whole.Finally,the boiler exhaust tem-perature can be reduced and the boiler efficiency and unit heat efficiency can be enhanced.%针对回转式空气预热器的旋转特性、低温腐蚀堵灰特征以及出口烟气温度分布规律,提出了在空气预热器入口设置非平衡换热器,将烟道分隔为几个小烟道,通过适度地降低各个小烟道的入口烟气温度,使锅炉排烟温度分布趋于平衡并整体有所降低,最终达到进一步降低锅炉排烟温度的目的,提高锅炉热效率或机组热效率。

  19. Air Distribution in a Room and Design Considerations of Mixing Ventilation by Flow Elements

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Jensen, Rasmus Lund; Pedersen, D. N.

    2001-01-01

    The paper shows detailed measurements of the air distribution in a room ventilated by mixing ventilation according to the specifications given by the International Energy Agency work. (Energy Conservation in Buildings and Community Systems Programme, Annex 20). It describes a number of flow...... elements and how they are used as design tools. The flow elements are the throw of an isothermal jet and the change in jet velocity when the jet moves from the upper to the lower part of the room. A third flow element is the penetration length of a non-isothermal wall jet....

  20. Torque characteristics in a large permanent magnet synchronous generator with stator radial ventilating air ducts

    Institute of Scientific and Technical Information of China (English)

    He HAO; Wei-zhong FEI; Dong-min MIAO; Meng-jia JIN; Jian-xin SHEN

    2016-01-01

    In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used fi rst to improve the torque characteristics using two-dimensional fi nite element analysis (FEA) in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The infl uences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.

  1. Solutions for Energy Efficient and Sustainable Heating of Ventilation Air: A Review

    Directory of Open Access Journals (Sweden)

    A. Žandeckis

    2015-10-01

    Full Text Available A high energy efficiency and sustainability standards defined by modern society and legislation requires solutions in the form of complex integrated systems. The scope of this work is to provide a review on technologies and methods for the heating of ventilation air as a key aspect for high energy and environmental performance of buildings located in a cold climate. The results of this work are more relevant in the buildings where space heating consumes a significant part of the energy balance of a building, and air exchange is arranged in an organized manner. A proper design and control strategy, heat recovery, the use of renewable energy sources, and waste heat are the main aspects which must be considered for efficient and sustainable ventilation. This work focuses on these aspects. Air conditioning is not in the scope of this study.

  2. CAN SORBENT-BASED GAS PHASE AIR CLEANING FOR VOCS SUBSTITUTE FOR VENTILATION IN COMMERCIAL BUILDINGS?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William; Fisk, William J.

    2007-08-01

    This paper reviews current knowledge about the suitability of sorbent-based air cleaning for removing volatile organic compounds (VOCs) from the air in commercial buildings, as needed to enable reductions in ventilation rates and associated energy savings. The principles of sorbent air cleaning are introduced, criteria are suggested for sorbent systems that can counteract indoor VOC concentration increases from reduced ventilation, major findings from research on sorbent performance for this application are summarized, and related priority research needs are identified. Major conclusions include: sorbent systems can remove a broad range of VOCs with moderate to high efficiency, sorbent technologies perform effectively when challenged with VOCs at the low concentrations present indoors, and there is a large uncertainty about the lifetime and associated costs of sorbent air cleaning systems when used in commercial buildings for indoor VOC control. Suggested priority research includes: experiments to determine sorbent system VOC removal efficiencies and lifetimes considering the broad range and low concentration of VOCs indoors; evaluations of in-situ regeneration of sorbents; and an updated analysis of the cost of sorbent air cleaning relative to the cost of ventilation.

  3. Experimental research on the indoor temperature and humidity fields in radiant ceiling air-conditioning system under natural ventilation

    Science.gov (United States)

    Huang, Tao; Xiang, Yutong; Wang, Yonghong

    2017-05-01

    In this paper, the indoor temperature and humidity fields of the air in a metal ceiling radiant panel air conditioning system with fresh air under natural ventilation were researched. The temperature and humidity distributions at different height and different position were compared. Through the computation analysis of partial pressure of water vapor, the self-recovery characteristics of humidity after the natural ventilation was discussed.

  4. Experimental analysis of an air-to-air heat recovery unit for balanced ventilation systems in residential buildings

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Diz, Ruben; Uhia, Francisco J.; Dopazo, Alberto; Ferro, Jose M. [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No. 9, 36310 Vigo (Spain)

    2011-01-15

    This paper deals with the experimental analysis of an air-to-air heat recovery unit equipped with a sensible polymer plate heat exchanger (PHE) for balanced ventilation systems in residential buildings. The PHE is arranged in parallel triangular ducts. An experimental facility was designed to reproduce the typical outdoor and exhaust air conditions with regard to temperature and humidity. The unit was tested under balanced operation conditions, as commonly used in practice. A set of tests was conducted under the reference operating conditions to evaluate the PHE performance. Afterwards, an experimental parametric analysis was conducted to investigate the influence of changing the operating conditions on the PHE performance. Experiments were carried out varying the inlet fresh air temperature, the exhaust air relative humidity and the air flow rate. The experimental results are shown and discussed in this paper. (author)

  5. Ventilation, good indoor air quality and rational use of energy

    DEFF Research Database (Denmark)

    Clausen, Geo; Fernandes, E. D. O.; DeGids, W.;

    2003-01-01

    The aim of this report is to provide information and advice to policy and decission makers, researchers, architects, designers, and manufacturers on strategies for achieving a good balance between good indoor air quality (IAQ) and the rational use of Energy in buildings, available guidelines...

  6. The Effects of Air Permeability, Background Ventilation and Lifestyle on Energy Performance, Indoor Air Quality and Risk of Condensation in Domestic Buildings

    Directory of Open Access Journals (Sweden)

    Arman Hashemi

    2015-04-01

    Full Text Available Effective and efficient ventilation is essential when improving energy performance and Indoor Air Quality (IAQ of buildings. Reducing air permeability can considerably improve the energy performance of buildings; however, making the buildings more airtight may result in lower rates of natural ventilation which may in turn increase the risks of condensation and unacceptable IAQ. This study evaluates the effects of different air permeability rates, background ventilation and occupants’ lifestyles on the energy performance as well as the risk of condensation and CO2 concentration in domestic buildings. Dynamic computer simulations were conducted in EnergyPlus. Results indicated direct relations between the ventilation rates, energy performance and IAQ. Higher air permeability along with background ventilation resulted in considerably better IAQ while energy consumption increased by up to four times. Occupants’ lifestyles were identified as a major contributor to the risk of condensation.

  7. Air compressor battery duration with mechanical ventilation in a field anesthesia machine.

    Science.gov (United States)

    Szpisjak, Dale F; Giberman, Anthony A

    2015-05-01

    Compressed air to power field anesthesia machine ventilators may be supplied by air compressor with battery backup. This study determined the battery duration when the compPAC ventilator's air compressor was powered by NiCd battery to ventilate the Vent Aid Training Test Lung modeling high (HC = 0.100 L/cm H2O) and low (LC = 0.020 L/cm H2O) pulmonary compliance. Target tidal volumes (VT) were 500, 750, and 1,000 mL. Respiratory rate = 10 bpm, inspiratory-to-expiratory time ratio = 1:2, and fresh gas flow = 1 L/min air. N = 5 in each group. Control limits were determined from the first 150 minutes of battery power for each run and lower control limit = mean VT - 3SD. Battery depletion occurred when VT was below the lower control limit. Battery duration ranged from 185.8 (±3.2) minutes in the LC-1000 group to 233.3 (±3.6) minutes in the HC-750 group. Battery duration of the LC-1000 group was less than all others (p = 0.027). The differences among the non-LC-1000 groups were not clinically significant. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  8. Analysis of thermal comfort and indoor air quality in a mechanically ventilated theatre

    Energy Technology Data Exchange (ETDEWEB)

    Kavgic, M.; Mumovic, D.; Young, A. [The Bartlett School of Graduate Studies, University College London, Gower Street, London, WC1E 6BT, England (United Kingdom); Stevanovic, Z. [Institute of Nuclear Sciences - Vinca, P.O. Box 522, 11001 Belgrade (RS)

    2008-07-01

    Theatres are the most complex of all auditorium structures environmentally. They usually have high heat loads, which are of a transient nature as audiences come and go, and from lighting which changes from scene to scene, and they generally have full or nearly full occupancy. Theatres also need to perform well acoustically, both for the spoken word and for music, and as sound amplification is less used than in other auditoria, background noise control is critically important. All these factors place constraints on the ventilation design, and if this is poor, it can lead to the deterioration of indoor air quality and thermal comfort. To analyse the level of indoor air quality and thermal comfort in a typical medium-sized mechanically ventilated theatre, and to identify where improvements could typically be made, a comprehensive post-occupancy evaluation study was carried out on a theatre in Belgrade. The evaluation, based on the results of monitoring (temperature, relative humidity, CO{sub 2}, air speed and heat flux) and modelling (CFD), as well as the assessment of comfort and health as perceived by occupants, has shown that for most of the monitored period the environmental parameters were within the standard limits of thermal comfort and IAQ. However, two important issues were identified, which should be borne in mind by theatre designers in the future. First, the calculated ventilation rates showed that the theatre was over-ventilated, which will have serious consequences for its energy consumption, and secondly, the displacement ventilation arrangement employed led to higher than expected complaints of cold discomfort, probably due to cold draughts around the occupants' feet. (author)

  9. Design of Air Ventilation System for Cargo Hold Vessels Using Solar Desiccant

    Directory of Open Access Journals (Sweden)

    Alam Baheramsyah

    2017-09-01

    Full Text Available One of the facilities and infrastructure of the vessel is the ventilation system in the cargo hold to maintain the quality. One attempt to avoid high moisture ratios is to provide a dry air supply by using desiccants. The purpose of this thesis is to design the system of air ventilation with solar desiccant by analysis the calculation with decrease air humidity ratio after passing desiccant rotor as well as fulfillment needs of heater and cooling system using heat of exhaust gas and seawater as well as fulfillment of electricity need using solar energy. From the result of analysis obtain to provide air supply in the cargo hold of 437.5 m3 / hour, the specification of rotor desiccant has a diameter of 550 mm with thickness 200 mm to decrease ratio of outside air humidity equal to 83.1% become 46.5%. Dehumidification air temperature of 47.7oC will be lowered to 35oC by using the sea water cooling media. As for the reactivation air heater requirement of 24.292 kW would be to fulfilled by utilizing the exhaust power of 498.12 kW. And for the electric power needs of the syetm is 34,488 wp will be supplied from the total solar module is 33 units with 345 wp per-capacity.

  10. Quantifying the impact of traffic-related air pollution on the indoor air quality of a naturally ventilated building.

    Science.gov (United States)

    Tong, Zheming; Chen, Yujiao; Malkawi, Ali; Adamkiewicz, Gary; Spengler, John D

    2016-01-01

    Improper natural ventilation practices may deteriorate indoor air quality when in close proximity to roadways, although the intention is often to reduce energy consumption. In this study, we employed a CFD-based air quality model to quantify the impact of traffic-related air pollution on the indoor air quality of a naturally ventilated building. Our study found that the building envelope restricts dispersion and dilution of particulate matter. The indoor concentration in the baseline condition located 10m away from the roadway is roughly 16-21% greater than that at the edge of the roadway. The indoor flow recirculation creates a well-mixed zone with little variation in fine particle concentration (i.e., 253nm). For ultrafine particles (road is observed due to Brownian and turbulent diffusion. In addition, the indoor concentration strongly depends on the distance between the roadway and building, particle size, wind condition, and window size and location. A break-even point is observed at D'~2.1 (normalized distance from the roadway by the width of the road). The indoor particle concentration is greater than that at the highway where D'air intakes are important to the indoor air quality of existing buildings adjacent to roadways.

  11. Human Response to Ductless Personalized Ventilation with Local Air Cleaning: Air Quality and Prevalence of SBS Symptoms

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Bivolarova, Maria; Fillon, Maelys

    2013-01-01

    ) and six workstations, three of which had DPV. The DV kept air temperature in the occupied zone (1.1 m above the floor). Pollution load was simulated by PVC floor covering and the bioeffluents generated by the subjects (60% recirculated room air). DPV sucked the air distributed over the floor by the DV...... and supplied it to the breathing zone of the subjects. The subjects were allowed to control the position of the DPV supply diffuser and the personalized flow rate. Each subject participated in five 4-hour experiments: 23 °C with DV only, 23 °C with DPV with air filter, 29 °C with DV only, 29 °C with DPV......The impact of local air cleaning and cooling of the head region by ductless personalized ventilation (DPV) on perceived air quality (PAQ) and Sick Building Syndrome (SBS) symptoms was studied. Thirty subjects participated in experiments performed in a test room with displacement ventilation (DV...

  12. Experimental study of perforated suspended ceilings as diffuse ventilation air inlets

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    2013-01-01

    An experimental study is reported in this paper for a diffuse ceiling ventilation concept. The analyses were carried out with two different porous surfaces mounted in a suspended ceiling: perforated tiles of aluminium and of gypsum. Ventilation air was supplied above the suspended ceiling...... to sustain the pressure of the plenum and ensure uni-directional airflow through the ceiling. Consequently only reverse flow of insignificant magnitude was observed which has a positive impact on the hygiene of the plenum. Furthermore, the measurements documented that the ceiling acts as a radiant cooling...... surface which increases the potential and applicability of the concept. Risk of thermal discomfort was not disclosed but the study did show evidence of large fluctuating air movements which could stem from transient behaviour creating sensations of draught to the occupants....

  13. Energy efficient biological air cleaning for farm stable ventilation; Energieffektiv biologisk luftrensning til staldventilation

    Energy Technology Data Exchange (ETDEWEB)

    Groenborg Nicolaisen, C.; Hansen, Mads P.R. [Teknologisk Institut, Aarhus (Denmark); Stroem, J.; Soerensen, Keld [DXT. Danish Exergy Technology A/S, Skoerping (Denmark); Goetke, C. [Lokalenergi Aarhus, Viby J. (Denmark); Morsing, S.; Soerensen, Lars C. [SKOV A/S, Roslev (Denmark); Ladegaerd Jensen, T.; Pedersen, Poul [Videncenter for svineproduktion, Copenhagen (Denmark)

    2013-05-01

    The project has been designed to reduce energy consumption for air purification by 30% while having a payback period of maximum 3 years. The project has achieved very significant results which are far above the target. Particularly satisfying is the wide range of new components that are launched in late 2012. By implementing the newly developed system at 100% cleaning (LPC 13 ventilators and Dynamic multistep control) in relation to Best Practice (SKOV's original system with DA600 fans) in a concrete pigsty, a saving of 61% and a simple payback of 1.7 years is achieved. Similarly, it is found that the energy used for pump operation can be reduced by 37% with the new Dynamic sprinkling control. At 20% cleaning a potential saving of 15% per year and a payback period of between 0 and 5 years was found, which is dependent on the desired performance as the capacities in the bio-filter's upper capacity range between 26 thousand to 30 thousand m3 / h entails costs for an additional extraction unit in the new solution. Furthermore, the newly developed components proved highly suitable for standard installations without air cleaning where a savings potential is 53% and the payback period 1.5 years. Product-wise, the project formed the basis for the development of: 1. New energy-efficient ventilation units (LPC11, 12,13) that are suitable for air purification; 2. A new energy-saving control principle (Dynamic Multi-Step) which is particularly suitable for low-energy ventilators; 3. A new energy-saving flow measurement system for ventilating ducts (Dynamic air to the central exhaust); 4. An energy-saving pressure control in common ducts (pressure control as a function of outside temperature); 5. Proposal for a new energy-saving pump operation for sprinkling of biological filters (Dynamic sprinkling). (LN)

  14. Assessment of ventilation efficiency for the study of indoor air quality; Appreciation de l'efficacite de la ventilation pour l'etude de la qualite de l'air interieur

    Energy Technology Data Exchange (ETDEWEB)

    Akoua, A.A.

    2004-10-15

    An efficient ventilation system provides a good indoor air quality by eliminating air pollutants and ensuring a satisfactory air renewal. Unlike most research works that deal with test cells with controlled boundary conditions, our study focuses on ventilation efficiency in a real environment. In situ experiments are performed and provide the boundary conditions necessary for CFD (Computational Fluid Dynamics) computations. Using CFD for predicting indoor air quality in a real environment is thus analyzed. The influence of permeability on numerical predictions quality is shown. Unfortunately, it is difficult to quantify accurately the air leakages and their airflow rates. Our study proposes a simplified model that includes air infiltration rates in the CFD computations, and that yields satisfactory results. A critical analysis of ventilation efficiency indices is then performed. It is shown that it is currently impossible to evaluate the air change efficiency ( a e ) in an occupied zone. Concerning the air pollutants removal effectiveness, it is shown that the usual index C e is not suited to ventilation systems with variable airflow rates. For such cases, a new formulation of this index is given. The ratio between the airflow rate and the nominal airflow rate of the ventilation system is also taken into consideration. A coupled analysis of this new index and of this airflow rate ratio enables us to assess the air pollutants removal effectiveness while considering the energetic cost of ventilation. We finally show that there is no universal index. The choice of the index depends on the pollutant, on the pollutant concentration, and on the airflow rate. A tool of decision-making aid is thus proposed in order to evaluate the air pollutants removal effectiveness for various ventilation systems. This tool is flexible and rather simple to use. (author)

  15. Ventilation filters as sources of air pollution – Processes occurring on surfaces of used filters

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Halás, Oto; Clausen, Geo

    2004-01-01

    ~ 35 and 55 ppb and slowly increased over time. Within an hour the ozone concentration downstream of the filter had increased to ~ 70 ppb. In contrast, no change in ozone removal efficiency over time was observed for a new filter. The used filter samples were then placed for 24 hours in ambient air......Ozone concentrations were monitored upstream and downstream of used filter samples following 24hours of ventilation with ozone- filtered air. The ozone concentration in the air upstream of the filters was maintained at ~75 ppb while the concentration downstream of the filters was initially between...... (ozone concentration air at an elevated temperature (100°C); or nitrogen. When subsequently placed in the air stream containing 75 ppb of ozone partial regeneration of the filter’s ozone removal capabilities was observed. Regeneration was greatest for the sample that had sat...

  16. Mining seams liable to spontaneous combustion using a system of automatic regulation of air pressure in a ventilation section

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    In mining coal seams liable to spontaneous combustion, the possibility of underground fire increases with growing depth of mining, as air depression in lower seams can suck the air from the goaf of upper levels through cracks and fissures in the roof. To preclude this possibility a system of automatic control of air pressure in a ventilated section of a coal mine has been worked out. The system, called SReDA-1, consists in complete isolation of the ventilated section from other workings by conventional means and in exact maintenance of air pressure equal to atmospheric pressure. Technical specifications of ventilating machines used in the SReDA-1 system are given. Scheme of ventilated section using the system is also shown. (In Russian)

  17. Microwave Disinfection in a Ventilation and Air-Conditioning System

    Institute of Scientific and Technical Information of China (English)

    LU Zhen; ZHANG Ji-li; MA Liang-dong; HE Juan

    2009-01-01

    Because of its broad spectrum and high efficiency,the microwave disinfection was used to control the airborne microbial contaminates in VAC system.Some microwave disinfection devices were developed com-bined with air filter,the design and calculation method was presented,and the disinfection effects on White staphylococcus,Staphylococcus aureus,Bacillus Subtilis,Escherichi coli were measured.The results show that the major influence factors on disinfection effect are microwave power,water-content of filter material,dis-infecting duration.After 15 min,the kill ratio is>90%,and the log value is>1.The microwave field is uni-form and the kill effect of bacteria on each surface of filter is the same,without statistically significant differ-ence.

  18. Heating, Ventilating, and Air-Conditioning: Recent Advances in Diagnostics and Controls to Improve Air-Handling System Performance

    Energy Technology Data Exchange (ETDEWEB)

    Wray, Craig; Wray, Craig P.; Sherman, Max H.; Walker, I.S.; Dickerhoff, D.J.; Federspiel, C.C.

    2008-02-01

    The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems.

  19. Preheating after N-flation

    CERN Document Server

    Battefeld, Diana

    2008-01-01

    We study preheating in N-flation, assuming the Mar\\v{c}enko-Pastur mass distribution, equal energy initial conditions at the beginning of inflation and equal axion-matter couplings, where matter is taken to be a single, massless bosonic field. By numerical analysis we find that preheating via parametric resonance is suppressed, indicating that the old theory of perturbative preheating is applicable. While the tensor-to-scalar ratio, the non-Gaussianity parameters and the scalar spectral index computed for N-flation are similar to those in single field inflation (at least within an observationally viable parameter region), our results suggest that the physics of preheating can differ significantly from the single field case.

  20. Talaromyces rubrifaciens, a new species discovered from heating, ventilation and air conditioning systems in China.

    Science.gov (United States)

    Luo, Yi; Lu, Xiaohong; Bi, Wu; Liu, Fan; Gao, Weiwei

    2016-01-01

    A new Talaromyces species, T. rubrifaciens, was isolated from supply air outlets of heating, ventilation and air conditioning (HVAC) systems in three kinds of public building in Beijing and Nanjing, China. Morphologically it exhibits many characters of section Trachyspermi but is distinguished from other species of this section by restricted growth and broad and strictly biverticillate conidiophores. Phylogenetic analyses based on the internal transcribed spacer rDNA (ITS), β-tubulin (BenA), calmodulin (CaM) and RNA polymerase second largest subunit (RPB2) genes reveal that T. rubrifaciens is a distinct species in section Trachyspermi. © 2016 by The Mycological Society of America.

  1. Indoor air quality and occupant satisfaction in five mechanically and four naturally ventilated open-plan office buildings

    DEFF Research Database (Denmark)

    Hummelgarrd, John; Juhl, Peter; Sæbjörnsson, Kristian

    2005-01-01

    The indoor air quality and occupant satisfaction was studied in five mechanically ventilated and four naturally ventilated open-plan office buildings in Copenhagen, using a simplified assessment procedure. Temperature and the concentration of CO2 were monitored in 2-10 locations per office...... to evaluate the variation throughout the offices. A representative measurement point was subsequently selected and measurements of the same parameters were made during one week. All offices were monitored during the same week and occupant responses to the indoor environment were collected via the Internet...... on the same day within that week. The study indicated that occupants in naturally ventilated offices have a lower prevalence of symptoms than those in mechanically ventilated offices. Although the room air temperature varied more and the concentration of CO2 was higher in the naturally ventilated offices...

  2. Investigation of optimal fluoroglass preheat

    CERN Document Server

    Baba, S; Toyoda, T; Wakamatsu, O; Machida, T

    2002-01-01

    The regular preheat condition of fluoroglass GD-301 (Chiyoda Technol Co., its size is 1.5 mm phi x 8.5 mm.) is temperature 70 deg C and time 30 minutes. When we measured dose 5.00 Gy at high energy X-ray processed with this condition, we observed build-up phenomenon according to elapsed days. So we investigated the optimal preheat temperature and time by measuring fluoroglass doses daily for several days. Fluoroglasses were irradiated 2.00 Gy of 10 MV X-ray at the reference depth using MEVATRON KD 2/50 PRIMUS (Toshiba Co.). First, we measured doses during 17 days after preheating them for 30 minutes, changing preheat temperatures from 50 deg C to 350 deg C at some intervals. Second, we measured doses during 9 days after preheating them at 70 deg C and at temperatures representing the maximum value and the most frequent value, changing preheat time from 5 minutes to 2 hours at some intervals. Doses increased up to around 115 deg C and decreased after that, and it seemed as if glasses were annealed at 350 deg C...

  3. Indoor Air Quality and ventilation assessment of rural mountainous households of Nepal

    Directory of Open Access Journals (Sweden)

    Indira Parajuli

    2016-12-01

    The mean CO and PM2.5 concentration for ICS and TCS are 27.11 ppm and 825.4 μg/m3 (27.11 ± 14.24 ppm and 825.4 ± 730.9 μg/m3 with significant correlation (p < 0.0001 and 36.03 ppm and 1336 μg/m3 (36.03 ± 19.06 and 1336 ± 952.8 with significant correlation (p < 0.0481, respectively. From the overall sample, the mean CO and PM2.5 concentration is reduced by 29.9% and 39%, respectively. The ventilation analysis result shows more than an 80 percentage deficit in ventilation as per the minimal rate of ventilation as prescribed by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE. Moreover, the placement of chimney at a short vertical height of 1.2 m adjoining to back window is the major cause of backflow. Therefore, the study has recommended a greater focus on ventilation to control IAQ of rural mountainous households.

  4. Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings.

    Science.gov (United States)

    Dutton, S M; Mendell, M J; Chan, W R; Barrios, M; Sidheswaran, M A; Sullivan, D P; Eliseeva, E A; Fisk, W J

    2015-02-01

    This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  5. Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    Jinze LV; Lizhong Zhu

    2013-01-01

    Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control,which significantly influences the transfer of pollutants between indoors and outdoors.To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants,a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants.During the period when the central ventilation system operated without air conditioning (AC-off period),concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels,due to the good linearity between indoor air and outdoor air (rp > 0.769,p < 0.05),and the slopes (1.2-4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs.During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period),although the total levels of PAHs were increased,the concentrations and percentage of the particulate PAHs indoors declined significantly.The BaP equivalency (BaPeq concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

  6. Natural ventilation without air breathing in the top openings of highway tunnels

    Science.gov (United States)

    Jin, Sike; Jin, Jiali; Gong, Yanfeng

    2017-05-01

    A number of urban shallow-buried highway tunnels have been built in China. Despite much better internal air quality compared to the traditional tunnels, there is no sufficient theoretical ground or experimental support for the construction of such tunnels. Most researchers hold that natural ventilation in such tunnels depends on air breathing in the top openings, but some others are skeptical about this conclusion. By flow visualization technology on a tunnel experiment platform, we tested the characteristics of airflow in the top openings of highway tunnels. The results showed that air always flowed from outside to inside in all top openings above a continuous traffic stream, and the openings did not breathe at all. In addition, intake air in the top openings reached its maximum velocity at the tunnel entrance, and then gradually slowed down with tunnel depth increasing.

  7. Indoor air quality, ventilation and respiratory health in elderly residents living in nursing homes in Europe

    DEFF Research Database (Denmark)

    Bentayeb, Malek; Norback, Dan; Bednarek, Micha

    2015-01-01

    European countries. 600 elderly people from 50 nursing homes underwent a medical examination and completed a standardised questionnaire. Air quality and comfort parameters were objectively assessed in situ in the nursing home. Mean concentrations of air pollutants did not exceed the existing standards...... cough. Elderly subjects aged ≥80 years were at higher risk. Pollutant effects were more pronounced in the case of poor ventilation. Even at low levels, indoor air quality affected respiratory health in elderly people permanently living in nursing homes, with frailty increasing with age. The effects were......Few data exist on respiratory effects of indoor air quality and comfort parameters in the elderly. In the context of the GERIE study, we investigated for the first time the relationships of these factors to respiratory morbidity among elderly people permanently living in nursing homes in seven...

  8. Indoor air quality, ventilation and respiratory health in elderly residents living in nursing homes in Europe.

    Science.gov (United States)

    Bentayeb, Malek; Norback, Dan; Bednarek, Micha; Bernard, Alfred; Cai, Guihong; Cerrai, Sonia; Eleftheriou, Konstantinos Kostas; Gratziou, Christina; Holst, Gitte Juel; Lavaud, François; Nasilowski, Jacek; Sestini, Piersante; Sarno, Giuseppe; Sigsgaard, Torben; Wieslander, Gunilla; Zielinski, Jan; Viegi, Giovanni; Annesi-Maesano, Isabella

    2015-05-01

    Few data exist on respiratory effects of indoor air quality and comfort parameters in the elderly. In the context of the GERIE study, we investigated for the first time the relationships of these factors to respiratory morbidity among elderly people permanently living in nursing homes in seven European countries. 600 elderly people from 50 nursing homes underwent a medical examination and completed a standardised questionnaire. Air quality and comfort parameters were objectively assessed in situ in the nursing home. Mean concentrations of air pollutants did not exceed the existing standards. Forced expiratory volume in 1 s/forced vital capacity ratio was highly significantly related to elevated levels of particles with a 50% cut-off aerodynamic diameter of indoor air quality affected respiratory health in elderly people permanently living in nursing homes, with frailty increasing with age. The effects were modulated by ventilation. Copyright ©ERS 2015.

  9. Modulating ventilation - low cost VAV for office buildings. [Variable Air Volume]; Modulerende ventilation - low cost VAV til kontor-bygninger. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Hoej Christensen, A.; Olsen, Hans; Drivsholm, C.

    2012-02-15

    The report describes a concept for renovating older existing Constant Air Volume (CAV) ventilation systems to modulating low-cost Variable Air Volume (VAV) systems. The concept is based on the total ventilated area being divided into appropriate indoor climate zones, which can cover from one to several offices with similar climate needs. For this initial climate assessment two relatively ''simple'' tools were developed that can estimate the temperature level in one room from the ventilation airflow, heat loads, etc.: - BSimFast (24-hour mean temperature calculation according to SBI-196, 2000); - BSimLight (Temperature simulation based on Danvak Textbook of Heat and Climate Technology). The concept of 'one room' can also be extended to 'one zone' with appropriate assumptions. However, only one mean room temperature is calculated. The different climate zones were equipped with Halton HFB control unit at the air supply and exhaust side. The project the following feedback options were used: - HFB unit's damper opening degree (0 to 90 degrees); - HFB unit's current flow; - HFB unit's exhaust temperature; and feedback from: - Frequency transformer (fan speed); - The central static duct pressure at the ventilation unit. In the project a control algorithm is developed that ensures a robust control of the entire ventilation system without adverse cyclic variations, based among other things on the exhaust temperature for each climate zone, and with the requirement that at least one throttle valve is always at least 80% open. It turned out that information on the current partial air volumes was necessary in addition to the individual throttle settings. Otherwise, a cyclic variations could not be controlled..Thus, it was the exhaust temperature from individual climate zones that defined the respective volumes of air. The concept was implemented on a complete CAV system and on part of a large CAV system, respectively. (LN)

  10. Bed-integrated local exhaust ventilation system combined with local air cleaning for improved IAQ in hospital patient rooms

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Melikov, Arsen Krikor; Mizutani, Chiyomi;

    2016-01-01

    The performance of a ventilated mattress (VM) used as a bed-integrated local exhaust ventilation system combined with air cleaning fabric (acid-treated activated carbon fibre (ACF) fabric) was developed and studied. The separate and combined effect of the VM and the local air cleaning for reducing...... micro-environment was exhausted. Two modes of operation were studied: 1) the exhausted polluted air was discharged out of the room and 2) the polluted air was cleaned by the ACF material installed inside the mattress and recirculated back into the room. Both modes of operation efficiently reduced...

  11. Impact of airflow interaction on inhaled air quality and transport of contaminants in rooms with personalized and total volume ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Cermak, Radim; Kovar, O.

    2003-01-01

    The impact of airflow interaction on inhaled air quality and transport of contaminants between occupants was studied in regard to pollution from floor covering, human bioeffluents and exhaled air, with combinations of two personalized ventilation systems (PV) with mixing and displacement ventilat......The impact of airflow interaction on inhaled air quality and transport of contaminants between occupants was studied in regard to pollution from floor covering, human bioeffluents and exhaled air, with combinations of two personalized ventilation systems (PV) with mixing and displacement...

  12. Ventilation effectiveness

    CERN Document Server

    Mathisen, Hans Martin; Nielsen, Peter V; Moser, Alfred

    2004-01-01

    Improving the ventilation effectiveness allows the indoor air quality to be significantly enhanced without the need for higher air changes in the building, thereby avoiding the higher costs and energy consumption associated with increasing the ventilation rates. This Guidebook provides easy-to-understand descriptions of the indices used to mesure the performance of a ventilation system and which indices to use in different cases.

  13. Cashing in on VAM : capturing value by generating carbon offset credits from ventilation air methane abatement

    Energy Technology Data Exchange (ETDEWEB)

    Lakhan, S.; Buchanan, M. [Verdeo Group, Washington, DC (United States)

    2010-07-01

    The recent developments in greenhouse gas (GHG) policies and carbon offset markets have created an opportunity for coal mines to extract value from their ventilation air methane (VAM) emissions. The methane that is discharged from ventilation systems accounts for nearly half of all methane emissions from active coal mines in the United States. Some mining companies have already begun capitalizing on this revenue opportunity, and are in the process of designing and implementing VAM oxidation for emission abatement purposes. Using existing regenerative thermal oxidizer technology, coal mines with sufficiently high methane concentrations in their discharged ventilation air can develop projects with internal rates of return greater than 25 per cent, merely by monetizing the emission reduction to generate a tradable carbon offset credit. Although the federal carbon offset program in the United States depends on the passage of federal climate change legislation, many States have already begun developing their own cap-and-trade programs. Several voluntary programs have also developed frameworks to certify carbon offset projects and register credits. The Climate Action Reserve program has approved VAM oxidation as an eligible project type. 6 refs., 4 tabs.

  14. Ventilation Effectiveness

    DEFF Research Database (Denmark)

    Mundt, M.; Mathisen, H. M.; Moser, M.;

    Improving the ventilation effectiveness allows the indoor air quality to be significantly enhanced without the need for higher air changes in the building, thereby avoiding the higher costs and energy consumption associated with increasing the ventilation rates. This Guidebook provides easy...

  15. Reduced exposure to coughed air by a novel ventilation method for hospital patient rooms

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Brand, Marek

    2012-01-01

    A novel hospital bed integrated ventilation and cleaning unit (HBIVCU) for local airflow control and cleansing, limiting the airborne spread of contagious air coughed from a sick patient in a hospital room, was developed. The performance efficiency of the unit, to successfully reduce occupants......’ exposure to coughed air, was studied in a full-scale, two-bed hospital room mock-up, 4.65 m x 4.65 m x 2.60 m (W x L x H), with two patients and a doctor. Four units were placed along the two sides of both beds close to the head. The room was ventilated by overhead mixing air distribution at 22 °C room air...... beside the bed and facing the coughing patient. The generated cough consisted of 100% CO2. The mouth was simulated by a circular opening of 0.021 m diameter. The characteristics of the cough were: peak flow - 10 L/s, cough volume - 2.5 L, duration - 0.5 s and maximum velocity - 28.9 m/s. The performance...

  16. Hospital ventilation standards and energy conservation: chemical contamination of hospital air. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rainer, D.; Michaelsen, G.S.

    1980-03-01

    In an era of increasing energy conservation consciousness, a critical reassessment of the validity of hospital ventilation and thermal standards is made. If current standards are found to be excessively conservative, major energy conservation measures could be undertaken by rebalancing and/or modification of current HVAC systems. To establish whether or not reducing ventilation rates would increase airborne chemical contamination to unacceptable levels, a field survey was conducted to develop an inventory and dosage estimates of hospital generated airborne chemical contaminants to which patients, staff, and visitors are exposed. The results of the study are presented. Emphasis is on patient exposure, but an examination of occupational exposure was also made. An in-depth assessment of the laboratory air environment is documented. Housekeeping products used in survey hospitals, hazardous properties of housekeeping chemicals and probable product composition are discussed in the appendices.

  17. Seat-integrated localized ventilation for exposure reduction to air pollutants in indoor environments

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Rezgals, Lauris; Melikov, Arsen Krikor

    2016-01-01

    generated before they disperse around a room. The polluted near the body air is exhausted into the cushion and it is removed from the room by a separate exhaust system. The performance of the method was studied in series of experiments. Full-scale room and a dressed thermal manikin sitting in front...... of a desk were used to simulate one person office. The chair on which the thermal manikin was sitting had the ventilated cushion (VC). Tracer gases, carbon dioxide (CO2) and nitrous oxide (N2O), were used to simulate bioeffluents emitted by the manikin’s armpits and groin region respectively...... from the cushion at 1.5, 3 and 5 L/s were performed. The pollution removal efficiency was assessed by measuring the pollution concentration in the breathing zone of the manikin and at several other locations in the room bulk air. Exhausting air through the VC decreased the concentration of the tracer...

  18. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...... this kind of collectors. The modified simulation program has been used for the determination of the surplus in performance which solar heating systems with this type of solar collectors for combined preheating of ventilation air and domestic hot water will have. The simulation program and the efficiency...

  19. Experimental analysis of energy performance of a ventilated window for heat recovery under controlled conditions

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend

    2011-01-01

    A ventilated window in cold climates can be considered as a passive heat recovery system. This study carried out tests to determine the thermal transmittance of ventilated windows by using the Guarded Hot Box. By testing under defined boundary conditions, the investigation described the heat......, it was found that a significant part of preheating occurred through the window frames, which positively influenced the heat recovery of the window but increased the heat loss. Results also showed that increasing air flow decreased the recovery efficiency until the point when the additional thermal...... transmittance introduced by the ventilation was higher than the effect of heat recovery. Accordingly, the use of the ventilated windows might be most suitable for window unit with low ventilation rates. The results correlated with theoretical calculations in standards and software. However, the concept...

  20. Gravitational-wave mediated preheating

    Directory of Open Access Journals (Sweden)

    Stephon Alexander

    2015-04-01

    Full Text Available We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.

  1. Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Lv, Jinze; Zhu, Lizhong

    2013-03-01

    Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (r(p) > 0.769, p supermarket increased the potential health risks from low molecular weight PAHs. During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

  2. Vocal Ergonomics in the Workplace: Heating, Ventilation, and Air-Conditioning Method Influences on Vocal Comfort and Function

    Science.gov (United States)

    Sandage, Mary J.; Rahn, Keith A.; Smith, Audrey G.

    2017-01-01

    Purpose: The purpose of this study was to examine the influence of the heating, ventilation, and air-conditioning method on voice function following a voicing task using ecologically valid offices, one with radiant HVAC and one with forced air. Method: A total of 12 consented participants (6 women, 6 men) narrated a video in each of 4…

  3. Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

    Science.gov (United States)

    Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

    2015-11-01

    This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

  4. Theoretical and experimental validation of the air changes in industrial ventilation optimization method

    Directory of Open Access Journals (Sweden)

    Borovitskiy A.A.

    2012-03-01

    Full Text Available Wide dissemination and development of industrial ventilation of different industries, which began in our country from the period of industrialization of the 30s years of the twentieth century has led to significant scientific and practical achievements noted in numerous books and articles. It also has a positive effect on the health of manufactures staff. More than 2.5 thousand different harmful substances and local suctions from them were investigated in detail by hygienists and engineers in the USSR, in Russia and abroad, but, unfortunately, have not been systematized and generalized. This article tries to make such generalization, corroborated by analytical relationships and dependencies experienced by different authors.This technique is based on the exponential-power dependence for the effectiveness of local suction, which is close to dependence, accepted in the study of turbulent diffusion, but in more general terms. The proposed in the article new term equivalent-effective rate is rather universal concept, which allows to compare the effectiveness of hazards trapping for different design, technological and aerodynamic parameters of the source and the suction of any kind. On the basis of this idea, an opportunity of the ventilation systems in industrial ventilation for numerous industrial processes optimization appeared.As a result of using this method the capital and operating costs for the equipment of these systems, steam curing, and air movement could be reduced, thereby significant technical and economic effect could be provided.

  5. [Biological contamination in office buildings related to ventilation/air conditioning system].

    Science.gov (United States)

    Bródka, Karolina; Sowiak, Małgorzata; Kozajda, Anna; Cyprowski, Marcin; Irena, Szadkowska-Stańczyk

    2012-01-01

    Indoor air is contaminated with microorganisms coming from both the atmospheric air and sources present in premises. The aim of this study was to analyze the concentrations of biological agents in office buildings, dependending on ventilation/air conditioning system and season. The study covered office buildings (different in the system of ventila-tion/air conditioning). Air samples for assessing the levels of inhalable dust, endotoxins and (1-->3)-beta-D-glucans, were taken at the selected stationary points of each building during summer and winter. The air was sampled for 6 h, using portable sets consisting of the GilAir 5 pump and the head filled with a filter of fiber glass. The samples for the presence of airborne bacteria and fungi were collected twice during the day using the impaction method. Average concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans in office premises were 0.09 mg/m3, 6.00 x 10(2) cfu/m3, 4.59 x 10(1) cfu/m3, 0.42 ng/m3 and 3.91 ng/m3, respectively. Higher concentrations of the investigated agents were found in summer. In premises with air conditioning concentrations of airborne fungi, (1-->3)-beta-D-glucans and inhalable dust were significantly lower in winter. In summer the trend was reverse except for (1-->3)-beta-D-glucans. Concentrations of biological agents were affected by the season and the presence of air conditioning. Concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans, observed inside the office buildings, were significantly higher in summer than in winter. The presence of the air conditioning system modified in various ways the levels of biological agents. Its influence was greater on the concentration of fungi and (1-->3)-beta-D-glucans than on that of bacteria and endotoxins.

  6. Air Filtration as Protection against Fouling of Ventilation and Air Conditioning Units

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Lajčíková, Ariana

    2005-01-01

    Currently, air filters are one of the most critical components of air treatment systems as they decontaminate the air delivered to living space. During the operation, however, the level of harmful surface deposits increases, and at certain times, an uncleaned filter can itself become a source...

  7. Air distribution in a multi-occupant room with mixing or displacement ventilation with or without floor or ceiling heating

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.

    2015-01-01

    This study performed a comparative analysis of the air distribution in a multi-occupant room with mixing or displacement ventilation and the effect of adding floor or ceiling heating to each of them. The vertical distribution of indoor air temperature and velocity in the occupied zone......; the mean local turbulence intensity varied from 12.0% to 14.1% with mixing ventilation with or without floor or ceiling heating, and the corresponding values were 1.5°C to 2.5°C and 7.3% to 9.8% with displacement ventilation with or without floor or ceiling heating. Mean air distribution effectiveness...... varied from 0.93 to 1.0 for mixing ventilation and from 1.06 to 1.14 for displacement ventilation with or without floor or ceiling heating. The results are relevant to the design and control of mixing and displacement ventilation with or without floor or ceiling heating in a multi-occupant room....

  8. Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts.

    Science.gov (United States)

    Rizzetto, R; Mansi, A; Panatto, D; Rizzitelli, E; Tinteri, C; Sasso, T; Gasparini, R; Crovari, P

    2008-03-01

    Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels. A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts. Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct. The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

  9. 新风换气机的应用与发展%Development and Application of Fresh Air Ventilator

    Institute of Scientific and Technical Information of China (English)

    石松; 段惠玲; 孙菁

    2015-01-01

    Good ventilation is an effective way to improve indoor air quality, human health can not be separated from the fresh air system, the indoor air quality is improved continuously by the fresh air ventilator with open loop system to provide sufficient fresh air indoors and reduce indoor harmful substances in the air content, with air purification in the very great degree. Fresh air ventilator with energy recovery, fresh air supply and polluted air removing can effectively solve the air pollution, in line with the public requirements on energy and air quality, meets the people’s pursuit of high quality life. The fresh air ventilator will be more and more widely used in our work and life with broad prospects for development.%良好的通风是提高室内空气品质的有效途径,人的健康离不开新风系统,新风换气机以开放式的循环系统持续改善室内空气质量,为室内提供足够的新风,降低了室内空气中各种有害物质的含量,在很大程度上也产生了净化空气的效果。新风换气机具有能量回收、供应新风同时排除污风的特点,能够有效地解决空气污染问题,符合大众对节能与空气品质的需求,满足人们对高品质生活的追求,将会在我们的工作和生活中得到越来越广泛的应用,具有广阔的发展前景。

  10. Modeled effectiveness of ventilation with contaminant control devices on indoor air quality in a swine farrowing facility.

    Science.gov (United States)

    Anthony, T Renée; Altmaier, Ralph; Park, Jae Hong; Peters, Thomas M

    2014-01-01

    Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5 °C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s(-1) (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures.

  11. The Influence of Office Furniture on the Air Movement in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Nielsen, June Richther

    Isothermal and thermal experiments and simulations form the basis of the investigations in this thesis. It is mainly the isothermal case that is studied. The examinations concern how normal office furniture influences the air movements in a mixing ventilated room. Especially, the jet under...... the ceiling is affected by the furniture and by the heat load. The velocity decay and the width of the jet are both increased. The maximum velocity in the occupied zone is increased by the furniture with a thermal load. The changes in the air movements in the room are partly caused by the furniture and partly...... show that the jet under the ceiling is insignificantly influenced by the normal office furniture. The maximum velocity in the occupied zone is reduced by the furniture and this reduction is dependent on the total length of the furniture in the main flow direction. When the total length of the furniture...

  12. Decentralized ventilation. Air conditioner of the future; Gedecentraliseerde ventilatie. De luchtbehandelingsinstallatie van de toekomst

    Energy Technology Data Exchange (ETDEWEB)

    Young, T. [Swegon Ltd, Kvaenum (Sweden); Hartmans, J.L.F. [Bergschenhoek, Berkel Rodenrijs (Netherlands)

    2005-11-01

    An overview is given of arguments to apply decentralized air conditioning systems instead of large central ventilation and air conditioning systems. It appears that savings can be realized with respect to investment, exploitation and the use of energy. [Dutch] Bij het ontwerpen van een ventilatie en/of luchtbehandelingssysteem voor gebouwen ging lange tijd de voorkeur uit naar het plaatsen van grote luchtbehandelingskasten die de ventilatie van het overgrote deel van het gebouw moesten regelen. De achterliggende gedachte hiervan was dat dit het goedkoopst zou zijn. Er zijn tal van redenen te bedenken waarom met een gedecentraliseerde luchtbehandelings-installatie veel beter op de investerings- en exploitatiekosten kan worden bespaard en een grotere efficientie van de energiebronnen kan worden bereikt. Ook kunnen in het ontwerp van de installatie bepaalde factoren worden opgenomen die bijdragen aan een veel beter totaal resultaat.

  13. A Literature Review on Heating of Ventilation Air with Large Diameter Earth Tubes in Cold Climates

    Directory of Open Access Journals (Sweden)

    Lili Tan

    2013-07-01

    Full Text Available Earth-air heat exchange (EAHE systems offer the possibility of reducing use of nonrenewable energy for heating ventilation air in cold climates. The number of installations of large diameter (greater than 900 mm EAHE systems reported for cold climates is small. Even less has been reported on their heating performance, but the available information suggests that further rigorous assessment is warranted to determine whether the reported better than expected temperature rise is supported and, if so, the reasons for this. Another concern is the possibility of long-term heat depletion in the surrounding soil, which would affect performance. Only a couple of short-term experimental studies of ground temperature effects of heating with EAHE were found for cool climates. Four articles that addressed ground temperature effects with horizontal ground source heat pump exchangers had conflicting findings regarding heat depletion in the soil.

  14. THE EFFECT OF VENTILATION AND ECONOMIZER ON ENERGY CONSUMPTIONS FOR AIR SOURCEHEAT PUMPS IN SCHOOLS

    Directory of Open Access Journals (Sweden)

    Nihal Al Raees

    2014-01-01

    Full Text Available The study discusses the applications of CO2-based demand-controlled ventilation DCV strategy integrated with the economizer for air source heat pumps in schools, investigates their impact on the annual heating, cooling and total energy consumption, also determines the potential savings achieved in different USA locations. The study includes detailed energy analysis on an existing middle school through whole building simulation energy software. The simulation model is first calibrated and checked for accuracy using actual monthly utility data. This model is then used for savings calculations resulted from a combination of air-side economizer and CO2-based DCV and with various occupancy profiles and locations. The results show that a significant saving could be obtained as compared to the actual operating strategy implemented in the existing system and this saving depends mainly on the actual occupancy profile and building locations.

  15. Air Filtration as Protection against Fouling of Ventilation and Air Conditioning Units

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Lajčíková, Ariana

    2005-01-01

    Currently, air filters are one of the most critical components of air treatment systems as they decontaminate the air delivered to living space. During the operation, however, the level of harmful surface deposits increases, and at certain times, an uncleaned filter can itself become a source...... of undesirable contaminents influencing negatively the IAQ of a living space. This is the phenomenon that has been a subject of the current research. The article presents a new, alternative view on indoor air contaminents and filtration requirements. It describes alternative means of filtration and assesses...... issues of inadequate maintenance and/or long term use of applied air filters. An experimental method of evealuating the air quality by means of chemical analysis and state-of-the-art spectrometer is also described....

  16. Effect of Environmental Deflector on Air Exchange in Slurry Pit and Concentration Distribution in a Two-dimensional Ventilation Chamber

    DEFF Research Database (Denmark)

    Tong, Guohong; Zhang, Guoqiang; Ravn, Peter

    2008-01-01

    Variations of air exchanges in slurry pit with four angles of an environmental deflector, namely 0° (parallel to the side wall or without deflector), 30°, 45° and 90°, were investigated using a tracer gas method. The investigations were performed in a two-dimensional ventilation chamber in the Air...... physics Lab, University of Aarhus. Ventilation rates used in the experiments were 100 and 200 m3/h. The experiment results showed that using the deflectors of 30°, 45° and 90° the airflow patterns were obviously changed in the room space near the slatted floor and in the head space of the pit compared...... with the setup without deflector. It was also found that of all the deflector angle performances with respect to air-exchange ratio and concentration distribution, the deflector position of 45° in two airflow rates cases behaved better with the lowest pit ventilation and the highest concentration in the head...

  17. Development of a Remotely Controlled Testing Platform with Low-drag Air-ventilated Hull

    Institute of Scientific and Technical Information of China (English)

    Konstantin I. Matveev; Nicholaus I. Perry; Alexander W. Mattson; Christopher S. Chaney

    2015-01-01

    This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept’s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.

  18. Observations of the Valley of Mexico Basin Ventilation Through the Tenango del Aire- Amecameca Geographical Gap

    Science.gov (United States)

    Ruiz-Suarez, G.; Torres-Jarón, R.; Steinbrecher, R.; Junkermann, W.; Torres-Jaramillo, A.; Garcia, A. R.; Mar-Morales, B.

    2007-05-01

    Past air quality modeling exercises have suggested the existence of basin drainage flows which may transport Mexico City Metropolitan Area's air pollution plume outside the Valley of Mexico Basin. The MCMA-2006 field campaign offered the opportunity to study the basin ventilation through a geographical gap in the southeast mountains of the basin. A mobile monitoring lab was placed at the Tenango del Aire town, a unique site located in this gap for measuring the pass of air masses from (and towards) the MCMA to (and from) the Cuautla Valley. O3, CO, NOx, NOy, CH2O global and UV radiation and MLH were measured continuously during MILAGRO from March 2 until April 6, together with other chemical species. Complementary backward and forward trajectories were constructed for the site using MCCM in prognostic mode during MILAGRO. An exploratory analysis of the air pollution roses measured at Tenango showed a sharp dominance of two flow patterns: one from the north well associated with relatively higher levels of primary pollutants and ozone levels; and another one from the south typically associated with lower levels primary pollutants but not so low of secondary ones as ozone. On the other hand, measured CO data at Tenango were compared with CO data measured at one local monitoring station in the town of Ocuituco in the State of Morelos. Ocuituco is located to the south of Tenango towards the Cuautla Valley. The preliminary results suggest that the back and forth pass of air masses through the Tenango del Aire - Amecameca area can be an important process in the regional transport of air pollution between two valleys and their metropolitan areas within the Central Mexico region.

  19. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  20. A Model for Air Flow in Ventilated Cavities Implemented in a Tool for Whole-Building Hygrothermal Analysis

    DEFF Research Database (Denmark)

    Grau, Karl; Rode, Carsten

    2006-01-01

    A model for calculating air flows in ventilated cavities has been implemented in the whole-building hygrothermal simulation tool BSim. The tool is able to predict indoor humidity conditions using a transient model for the moisture conditions in the building envelope.......A model for calculating air flows in ventilated cavities has been implemented in the whole-building hygrothermal simulation tool BSim. The tool is able to predict indoor humidity conditions using a transient model for the moisture conditions in the building envelope....

  1. Wearable Personal Exhaust Ventilation, WPEV: Improved Indoor Air Quality and Reduced Exposure to Air Exhaled from a Sick Doctor

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho D.; Barova, Maria; Melikov, Arsen K.

    2015-01-01

    Exposure reduction to exhaled air from a sick doctor wearing a personal exhaust unit incorporated in a headset-microphone was studied. Experiments were performed in a full-scale test room furnished as a double-bed hospital room with overhead ventilation at 3, 6, and 12 air changes per hour. Room...... air temperature was 22◦C. A breathing thermal manikin with a body size and shape similar to the body of an average Scandinavian woman was used to mimic a “sick” doctor. The manikin was equipped with artificial lungs with a realistic breathing cycle (2.5-sec inhalation, 2.5-sec exhalation, and 1-sec...... pause) and a tidal flow rate of 6 L/min. A second thermal manikin and heated dummy were used to resemble lying patients. Exhaled air by the doctor was mixed with tracer gas to mimic pathogens. The wearable personal exhaust unit was positioned frontally by the mouth of the doctor at three distances: 0...

  2. Long-distance transport of ventilated patients: advantages and limitations of air medical repatriation on commercial airlines.

    Science.gov (United States)

    Veldman, Alex; Diefenbach, Michael; Fischer, Doris; Benton, Alida; Bloch, Richard

    2004-01-01

    To illustrate the advantages and limitations of transporting ventilated intensive care unit patients over intercontinental distances on commercial airlines, this case series reports 8 ventilated patients repatriated by an air medical transport company. Eight ventilated patients, 3 suffering from internal and 5 from neurologic diseases. Distances ranged from 1700 to 10280 nautical miles with transport times from 04:10 hours to 21:55 hours. For 3 patients, a dedicated patient transport compartment (PTC) in the aircraft cabin was used. All patients were ventilator-dependent for a minimum of 11 days before transport (48 days median, 113 days maximum). One patient went into cardiac arrest during the flight and died. None of the other patients experienced any emergency or invasive procedures, other than peripheral venous access necessary during the flight. In all patients, ventilation was adjusted with respect to the blood gas analysis at least once during the transport. No technical failures or drop-outs occurred during the flights. None of the flights had to be diverted for technical or medical reasons. Long distance international transport of ventilated intensive care unit patients is an extremely cost intensive and logistically challenging task. In a certain subgroup of relatively stable ventilated patients, transport on commercial airlines offers advantages in terms of cost effectiveness and reduced transport time and acceleration/deceleration trauma as a result of multiple fuel stops.

  3. Study of Air Velocity and Temperature Gradient in Lecture Room Through Mixed and Displacement Ventilation Systems to Improve the Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Bambang Iskandriawan

    2010-05-01

    Full Text Available Air ventilation system is considered crucial in the target of maintaining clean and fresh room air at all times. It will improve the thermal comfort and indoor air quality along with the activities of occupant. This investigation explores the influence of fresh air diffuser location to the thermal comfort factor especially in the lecture room. It will contrast two types of ventilation: the mixed and the displacement ventilation. The thermal comfort factor is represented by means of air velocity and temperature. Using Fluent 6.2 as CFD (Computational Fluid Dynamics simulation program, all the variables will be exploited. The specific boundary type’s room model is verified in GAMBIT software generating such a specific lecture room. The finding shows that the displacement ventilation system has benefit in the propensity of controlling the heat and air velocity compare to the mixed ventilation

  4. Effect of ventilation on perceived quality of air polluted by building materials. A summary of reported data

    Energy Technology Data Exchange (ETDEWEB)

    Wargocki, P.; Vondruskova, J. (International Centre for Indoor Environment and Energy, Dept. of Mechanical Engineering, DTU, Kgs. Lyngby (DK)); Knudsen, Henrik N. (Danish Building Research Institute, Aalborg Univ., Hoersholm (DK))

    2007-02-15

    This paper summarizes existing data on how varying ventilation rates affect the perceived quality of air polluted by building materials. This is done by reviewing literature dealing with exposure-response relationships, i.e. the log-linear relationships between the concentration of pollutants (exposure) and the perceived air quality (response). The reviewed data originate from studies with single building materials performed in small-scale ventilated chambers and from studies carried out in a full-scale setting resembling normal offices. Perceived air quality expressed in terms of acceptability as assessed by untrained panels was included. The results show that the exposure-response relationships vary for different building materials as regards the impact of changing ventilation rate on perceived air quality and the level of perceived air quality at a constant ventilation rate. This applies both for the data collected in small-scale and in full-scale experiments. The differences may be caused by the experimental conditions, psychological factors, physiological factors, and chemical/physical factors. A well controlled study taking these factors into account with several different building materials, is thus recommended to further study whether the observed results have practical significance. These experiments should be carried out under realistic fullscale conditions. (au)

  5. Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    Displacement ventilation is an interesting new type of air distribution principle which should be considered in connection with design of comfort ventilation in both smal1 and large spaces. Research activities on displacement ventilation are large all over the world and new knowledge of design...... methods appears continuously. This book gives an easy introduction to the basis of displacement ventilation and the chapters are written in the order which is used in a design procedure. The main text is extended by five appendices which show some of the new research activities taking place at Aalborg...

  6. A study of energy use for ventilation and air-conditioning systems in Hong Kong

    Science.gov (United States)

    Yu, Chung Hoi Philip

    Most of the local modern buildings are high-rise with enclosed structure. Mechanical ventilation and air conditioning (MVAC) systems are installed for thermal comfort. Various types of MVAC systems found in Hong Kong were critically reviewed with comments on their characteristics in energy efficiency as well as application. The major design considerations were also discussed. Besides MVAC, other energy-consuming components in commercial buildings were also identified, such as lighting, lifts and escalators, office equipment, information technology facilities, etc. A practical approach has been adopted throughout this study in order that the end results will have pragmatic value to the heating, ventilating and air-conditioning (HVAC) industry in Hong Kong. Indoor Air Quality (IAQ) has become a major issue in commercial buildings worldwide including Hong Kong. Ventilation rate is no doubt a critical element in the design of HVAC systems, which can be realized more obviously in railway train compartments where the carbon dioxide level will be built up quickly when the compartments are crowded during rush hours. A study was carried out based on a simplified model using a train compartment that is equipped with an MVAC system. Overall Thermal Transfer Value (OTTV) is a single-value parameter for controlling building energy use and is relatively simple to implement legislatively. The local government has taken a first step in reacting to the worldwide concern of energy conservation and environmental protection since 1995. Different methods of OTTV calculation were studied and the computation results were compared. It gives a clear picture of the advantages and limitations for each method to the building designers. However, due to the limitations of using OTTV as the only parameter for building energy control, some new approaches to a total control of building energy use were discussed and they might be considered for future revision of the building energy codes in Hong

  7. Nonlinear Inflaton Fragmentation after Preheating

    CERN Document Server

    Felder, G N; Felder, Gary N.; Kofman, Lev

    2007-01-01

    We consider the nonlinear dynamics of inflaton fragmentation during and after preheating in the simplest model of chaotic inflation. While the earlier regime of parametric resonant particle production and the later turbulent regime of interacting fields evolving towards equilibrium are well identified and understood, the short intermediate stage of violent nonlinear dynamics remains less explored. Lattice simulations of fully nonlinear preheating dynamics show specific features of this intermediate stage: occupation numbers of the scalar particles are peaked, scalar fields become significantly non-gaussian and the field dynamics become chaotic and irreversible. Visualization of the field dynamics in configuration space reveals that nonlinear interactions generate non-gaussian inflaton inhomogeneities with very fast growing amplitudes. The peaks of the inflaton inhomogeneities coincide with the peaks of the scalar field(s) produced by parametric resonance. When the inflaton peaks reach their maxima, they stop ...

  8. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

    Science.gov (United States)

    Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  9. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    Science.gov (United States)

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  10. Air trapping on chest CT is associated with worse ventilation distribution in infants with cystic fibrosis diagnosed following newborn screening.

    Directory of Open Access Journals (Sweden)

    Graham L Hall

    Full Text Available BACKGROUND: In school-aged children with cystic fibrosis (CF structural lung damage assessed using chest CT is associated with abnormal ventilation distribution. The primary objective of this analysis was to determine the relationships between ventilation distribution outcomes and the presence and extent of structural damage as assessed by chest CT in infants and young children with CF. METHODS: Data of infants and young children with CF diagnosed following newborn screening consecutively reviewed between August 2005 and December 2009 were analysed. Ventilation distribution (lung clearance index and the first and second moment ratios [LCI, M(1/M(0 and M(2/M(0, respectively], chest CT and airway pathology from bronchoalveolar lavage were determined at diagnosis and then annually. The chest CT scans were evaluated for the presence or absence of bronchiectasis and air trapping. RESULTS: Matched lung function, chest CT and pathology outcomes were available in 49 infants (31 male with bronchiectasis and air trapping present in 13 (27% and 24 (49% infants, respectively. The presence of bronchiectasis or air trapping was associated with increased M(2/M(0 but not LCI or M(1/M(0. There was a weak, but statistically significant association between the extent of air trapping and all ventilation distribution outcomes. CONCLUSION: These findings suggest that in early CF lung disease there are weak associations between ventilation distribution and lung damage from chest CT. These finding are in contrast to those reported in older children. These findings suggest that assessments of LCI could not be used to replace a chest CT scan for the assessment of structural lung disease in the first two years of life. Further research in which both MBW and chest CT outcomes are obtained is required to assess the role of ventilation distribution in tracking the progression of lung damage in infants with CF.

  11. HVAC (heating, ventilation, air conditioning) literature in Japan: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Hane, G.J.

    1988-02-01

    Japanese businessmen in the heating, ventilation, air conditioning, and refrigeration (HVACandR) industry consider the monitoring of technical and market developments in the United States to be a normal part of their business. In contrast, efforts by US businessmen to monitor Japanese HVAC and R developments are poorly developed. To begin to redress this imbalance, this report establishes the groundwork for a more effective system for use in monitoring Japanese HVAC and R literature. Discussions of a review of the principal HVAC and R publications in Japan and descriptions of the type of information contained in each of those publications are included in this report. Since the Japanese HVAC and R literature is abundant, this report also provides practical suggestions on how a researcher or research manager can limit the monitoring effort to the publications and type of information that would most likely be of greatest value.

  12. Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

    Science.gov (United States)

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

  13. Simplified model for a ventilated glass window under forced air flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.A.R. [Depto. de Engenharia Termica e de Fluidos-FEM-UNICAMP CP: 6122 CEP 13083-970 Campinas, SP (Brazil); Henriquez, J.R. [Depto. de Eng. Mecanica-DEMEC, UFPE Av. Academico Helio Ramos, S/N CEP 50740-530, Recife, PE (Brazil)

    2006-02-01

    This paper presents a study on a ventilated window composed of two glass sheets separated by a spacing through which air is forced to flow. The proposed model is one dimensional and unsteady based upon global energy balance over the glass sheets and the flowing fluid. The external glass sheet of the cavity is subjected to variable heat flow due to the solar radiation as well as variable external ambient temperature. The exchange of radiation energy (infrared radiation) between the glass sheets is also included in the formulation. Effects of the spacing between the glass sheets, variation of the forced mass flow rate on the total heat gain and the shading coefficients are investigated. The results show that the effect of the increase of the mass flow rate is found to reduce the mean solar heat gain and the shading coefficients while the increase of the fluid entry temperature is found to deteriorate the window thermal performance. (author)

  14. METHODS FOR REPRESENTING THE TUBING OF VENTILATION/AIR-CONDITIONING PLANTS

    Directory of Open Access Journals (Sweden)

    MÂRZA Carmen

    2015-06-01

    Full Text Available The representation of ventilation or air conditioning plants, particularly of the tubing, specifically require the ability to "see into space" or, more completely expressed, to make the connection between the plane and the space. For this reason, in the study program of the "Building Services Engineering" these types of installations have a privileged role. Thus, the students learn the representation in 2D of these plants during the study of the discipline Technical Drawing and further they learn the representation methods in 2D and 3D using the AutoCAD software – respectively the subroutine CAD VENT. Finally, the undergraduates study - as an alternative - the axonometric representation of these plants, by using the Allplan software. The last one offers also elements of the tubes (pipes dimensioning. The paper presents teaching methods using concrete examples.

  15. Ontology for Life-Cycle Modeling of Heating, Ventilating, and Air Conditioning (HVAC) Systems: Experimental Applications Using Revit

    Science.gov (United States)

    2012-03-01

    Center, Construction Engineering Research Laboratory (ERDC-CERL) has developed a core life- cycle building information model ( BIM ) based on three...was to promote consistency and quality of content created for Building Information Models ( BIMs ) across various disciplines. The HVAC MVD was...MVD. 15. SUBJECT TERMS building information modeling ( BIM ), ontology, Army facilities, heating, ventilating, and air-conditioning (HVAC) systems

  16. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Logue, J. M.; Turner, W. J.N.; Walker, I. S.; Singer, B. C.

    2015-07-01

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector’s energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level.

  17. Solar Air Collectors for Space Heating and Ventilation Applications—Performance and Case Studies under Romanian Climatic Conditions

    Directory of Open Access Journals (Sweden)

    Sanda Budea

    2014-06-01

    Full Text Available Solar air collectors have various applications: on the one hand, they can be used for air heating in cold seasons; on the other hand they can be used in summer to evacuate the warm and polluted air from residential, offices, industrial, and commercial buildings. The paper presents experimental results of a solar collector air, under the climatic conditions of the Southeastern Europe. The relationships between the direct solar irradiation, the resulting heat flow, the air velocity at the outlet, the air flow rate, the nominal regime of the collector and the efficiency of conversion of solar energy into thermal energy are all highlighted. Thus, it was shown that after a maximum 50 min, solar air collectors, with baffles and double air passage can reach over 50% efficiency for solar irradiation of 900–1000 W/m2. The article also presents a mathematical model and the results of a computational program that allows sizing solar collectors for the transfer of air, with the purpose of improving the natural ventilation of buildings. The article is completed with case studies, sizing the area to be covered with solar collectors, to ensure ventilation of a house with two floors or for an office building. In addition, the ACH (air change per hour coefficient was calculated and compared.

  18. Evaluation of simplified ventilation system with direct air supply through the facade in a school in a cold climate

    Energy Technology Data Exchange (ETDEWEB)

    Mysen, M. [Norwegian Building Research Institute, Blindern, Oslo (Norway); Department of Energy and Process Technology, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Schild, P. G.; Hellstrand, V.; Thunshelle, K. [Norwegian Building Research Institute, Blindern, Oslo (Norway)

    2004-07-01

    Many educational buildings in industrialised countries have poor indoor climate, according to today's knowledge about the impact of indoor climate on well-being and productivity. Budget restrictions and practical limitations such as lack of space for central air handling units and ventilation ducts, have motivated the application of simplified ventilation systems in some schools, such as taking unconditioned supply air directly from the facade. One such school was recently evaluated in Norway. On cold days, thermal comfort in the classroom deteriorated due to cold down draught from the supply outlet. In addition, moist and fertile conditions for microbiological growth were observed in the air supply ductwork. On the other hand the same pupils are more satisfied with the school and have less sick building syndrome (SBS) symptoms during winter than summer. An improved control strategy with a temperature-compensated CO{sub 2} set-point for controlling the air flow is suggested. This could improve thermal comfort and reduce energy use without compromising perceived air quality (PAQ) during cold weather. Furthermore it could improve indoor air quality (IAQ) during warm weather with only a slight increase of energy use. Further evaluation of an improved solution is needed before such a ventilation concept can be recommended in cold climates. (author)

  19. Review of low-energy construction, air tightness, ventilation strategies and indoor radon: results from Finnish houses and apartments.

    Science.gov (United States)

    Arvela, H; Holmgren, O; Reisbacka, H; Vinha, J

    2014-12-01

    Low-energy and passive house construction practices are characterised by increased insulation, high air tightness of the building shell and controlled mechanical ventilation with heat recovery. As a result of the interaction of mechanical ventilation and high air tightness, the pressure difference in a building can be markedly enhanced. This may lead to elevated indoor radon levels. Minor leakages in the foundation can affect the radon concentration, even in the case where such leaks do not markedly reduce the total air tightness. The potential for high pressures to affect indoor radon concentrations markedly increases when the air tightness ACH50, i.e. the air change per hour induced by a pressure difference of 50 Pa, is houses having mechanical supply and exhaust ventilation with heat recovery (MSEV) are typically 2-3 Pa, clearly lower than the values of 5-9 Pa in houses with only mechanical exhaust ventilation (MEV). In MSEV houses, radon concentrations are typically 30% lower than in MEV houses. In new MSEV houses with an ACH50 of 0.6 h(-1), the limit for passive construction, the analytical estimates predict an increase of 100% in the radon concentration compared with older houses with an ACH50 of 4.0 h(-1). This poses a challenge for efficient radon prevention in new construction. Radon concentrations are typically 30% lower in houses with two storeys compared with only one storey. The introduction of an MSEV ventilation strategy in typically very airtight apartments has markedly reduced pressure differences and radon concentrations.

  20. Laboratory evaluation of welder's exposure and efficiency of air duct ventilation for welding work in a confined space.

    Science.gov (United States)

    Ojima, J; Shibata, N; Iwasaki, T

    2000-01-01

    CO2 arc welding in a confined space was simulated in a laboratory by manipulating a welding robot which worked in a small chamber to experimentally evaluate the welder's exposure to welding fumes, ozone and carbon monoxide (CO). The effects of the welding arc on the air temperature rise and oxygen (O2) concentration in the chamber were also investigated. The measuring points for these items were located in the presumed breathing zone of a welder in a confined space. The time averaged concentrations of welding fumes, ozone and CO during the arcing time were 83.55 mg/m3, 0.203 ppm and 0.006%, respectively, at a welding current of 120A-200A. These results suggest serious exposure of a welder who operates in a confined space. Air temperature in the chamber rose remarkably due to the arc heat and the increase in the welding current. No clear decrease in the O2 concentration in the chamber was recognized during this welding operation. A model of air duct ventilation was constructed in the small chamber to investigate the strategy of effective ventilation for hazardous welding contaminants in a confined space. With this model we examined ventilation efficiency with a flow rate of 1.08-1.80 m3/min (ventilation rate for 0.40-0.67 air exchanges per minute) in the chamber, and proved that the exposure level was not drastically reduced during arcing time by this air duct ventilation, but the residual contaminants were rapidly exhausted after the welding operation.

  1. Building envelope design for renewal of air by natural ventilation in moderate climates. Proposition of a designing methodology; Conception des enveloppes de batiments pour le renouvellement d'air par ventilation naturelle en climats temperes. Proposition d'une methodologie de conception

    Energy Technology Data Exchange (ETDEWEB)

    Mansouri, Y.

    2003-12-01

    The subject of this research is to produce methods and methodological tools for the architects to support the integration of natural ventilation systems in the building envelope design. Our research is situated to the interface between the architectural practice and the physical research on natural ventilation. We are interested in phenomena that can influence or force the strategy of ventilation. A morphological analysis of naturally ventilated buildings concerning the integration modes of natural ventilation systems is done permitting US to propose a typology and a topology of ventilation systems. We define criteria in relation to the thermal comfort, to the quality of air and the economy of energy to assess air renewal techniques. In complement of the sizing tool, we elaborate a methodology of conception for the integration of passives ventilation systems. Design guidelines permit US to conclude on an effective natural ventilation system which is well adapted to collective habitat. (author)

  2. Performance of personalized ventilation in a room with an underfloor air distribution system: transport of contaminants between occupants

    DEFF Research Database (Denmark)

    Cermak, Radim; Melikov, Arsen Krikor

    2003-01-01

    the workplaces has not been studied in detail. This paper presents a study on the performance of a personalized ventilation system installed in a full-scale test room with an underfloor air distribution system. Transport of human-produced airborne pollutants (in real life they can be infectious agents) between...... by the exposed manikin. The main conclusion is that the design of the personalised ventilation system and the interaction of personalized airflow and room airflow should be carefully considered in order to achieve minimal transport of pollution between occupants....

  3. Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

    Science.gov (United States)

    Simmons, R B; Crow, S A

    1995-01-01

    New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

  4. Preheating with Trilinear Interactions: Tachyonic Resonance

    CERN Document Server

    Dufaux, J F; Kofman, L; Peloso, M; Podolsky, D

    2006-01-01

    We investigate the effects of bosonic trilinear interactions in preheating after chaotic inflation. A trilinear interaction term allows for the complete decay of the massive inflaton particles, which is necessary for the transition to radiation domination. We found that typically the trilinear term is subdominant during early stages of preheating, but it actually amplifies parametric resonance driven by the four-legs interaction. In cases where the trilinear term does dominate during preheating, the process occurs through periodic tachyonic amplifications with resonance effects, which is so effective that preheating completes within a few inflaton oscillations. We develop an analytic theory of this process, which we call tachyonic resonance. We also study numerically the influence of trilinear interactions on the dynamics after preheating. The trilinear term eventually comes to dominate after preheating, leading to faster rescattering and thermalization than could occur without it. Finally, we investigate the...

  5. Survey of air pollutants emitted from rendering plant of poultry slaughterhouse and design of local ventilation system and suitable collector for control and treatment of air pollutants

    Directory of Open Access Journals (Sweden)

    Gh Hesam

    2014-07-01

    Conclusion: Application of local exhaust ventilation system and integrated collectors for control of air pollutants in rendering plant can remove large amounts of particulate and gaseous pollutants. Control of these pollutants can cause loss of smell nuisance and environmental pollution and improving the health and welfare of workers and neighboring residents of such industries.

  6. Clinical applications of preheated hybrid resin composite.

    Science.gov (United States)

    Rickman, L J; Padipatvuthikul, P; Chee, B

    2011-07-22

    This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements.

  7. Blower/air cooler with internally finned tubes; Ventilator-Luftkuehler mit innenberippten Rohren

    Energy Technology Data Exchange (ETDEWEB)

    Arnemann, M. [FKU - Forschungszentrum fuer Kaelte- und Umwelttechnik, Berlin (Germany)

    1997-12-31

    Heat transfer is higher in finned tubes than in smooth tubes. In order to assess the extent of improvement, internal heat tranfer coefficients and pressure losses of smooth and finned tubes were investigated on behalf of Walter Roller GmbH and Co. Two blower-type air coolers of identical design (except for the tubes) were investigated in a calorimeter using R22 and different refrigerant mass flows, evaporation temperatures and air temperatures. The results are the basis for new develoments by Walter Roller. Energetic assessment of the new type of evaporator was made on the basis of the DIN 8955 and ENV 328 standards. The results and findings are presented. (orig.) [Deutsch] Der Einsatz von innenberippten Rohren laesst im Vergleich mit glatten Rohren einen deutlich verbesserten inneren Waermeuebergang erwarten. Zur Abschaetzung der Groessenordnung dieser Verbesserungen wurden im Auftrag der Firma Walter Roller GmbH and Co. die inneren Waermeuebergangskoeffizienten und die Druckverluste von glatten und innenberippten Rohren experimentell bestimmt. Dazu wurden zwei bis auf die Rohre baugleiche Ventilator-Luftkuehler ineinem Kalorimeter untersucht. Mit dem Kaeltemittel R22 wurden fuer verschiedene Kaeltemittelmassenstroeme, Verdampfungstemperaturen und Lufttemperaturen die Kennzahlen bestimmt, die zur Charakterisierung der Rohre dienlich sind. Die Ergebnisse bildeten die Grundlage fuer eine Neuentwicklung im Hause Walter Roller. Die energetische Bewertung des neuen Verdampfertyps erfolgte in Anlehnung an die Normen DIN 8955 bzw. ENV 328. Die Untersuchungen und die Ergebnisse werden praesentiert. (orig.)

  8. Numerical Simulation of Inter-Flat Air Cross-Contamination under the Condition of Single-Sided Natural Ventilation

    DEFF Research Database (Denmark)

    Liu, Xiaoping; Niu, Jianlei; Perino, Marco

    2008-01-01

    the two sides, each of which has a flat fa ade with openable windows. When the wind speed is extremely low, with doors closed and windows opened, the flats become single-sided naturally ventilated driven by buoyancy effects. The air pollutants can travel from a lower flat to a vertically adjacent upper...... flat through open windows, caused by indoor/outdoor temperature-difference induced buoyancy. Computational fluid dynamics is employed to explore the characteristics of this process. Based on the comparison with experimental data about the air flow distribution in and around a single-sided naturally...... ventilated room, the renormalization group based k-ε model, together with carbon dioxide used as a tracer, is chosen to reveal this air cross-contamination. The simulation results are in agreement with our prior on-site tracer-gas measurements, revealing that the windows flush with a flat fa ade can...

  9. Experimental study of the heat transfers and passive cooling potential of a ventilated plenum designed for uniform air distribution

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Lessing, Julian

    2016-01-01

    suspended ceiling to uniformly distribute the supply air to the occupied zone. This, in effect, increases the thermal mass of the room because the upper slab of the room no longer is isolated from the occupied zone. In this study, the cooling potential of a diffuse ceiling ventilation system...... is investigated by experiments focused toward characterizing the convective heat transfer of the plenum. The heat transfers are quantified from four different air flow rates, the temperature of the air supplied to the plenum and the mean surface temperature, i.e. the total heat transfer coefficient of the plenum...... with unventilated plenum. In conclusion this study disclosed the mean heat transfer of the plenum with an inlet jet of approx. 1.2-0.4 m/s and temperature differences of 0.5-4.5 °C and showed that ventilation supply through the plenum can be used to augment the night cooling potential....

  10. Laboratory study on the cooling effect of flash water evaporative cooling technology for ventilation and air-conditioning of buildings

    DEFF Research Database (Denmark)

    Fang, Lei; Yuan, Shu; Yang, Jianrong

    2016-01-01

    This paper presents a simple cooling technology using flash water evaporation. The technology combines a water atomizer with a plate heat exchanger used for heat recovery of a ventilation system. It is mainly used to cool the ventilation airflow from outdoors and is particularly suitable to be used...... in warm/hot and dry environment where dehumidification of outdoor air is not needed. A laboratory experiment was designed and conducted to evaluate the cooling effectiveness of this technology. The experiment was conducted in a twin-climate chamber. One chamber simulated warm/hot and dry outdoor...... environments and the other simulated an air-conditioned indoor environment. The flash water evaporation cooling device was installed in the chamber that simulated indoor environment. The air from the chamber simulating outdoor environment was introduced into the cooling device and cooled by the flash water...

  11. Thermal comfort in the humid tropics: Field experiments in air conditioned and naturally ventilated buildings in Singapore

    Science.gov (United States)

    de Dear, R. J.; Leow, K. G.; Foo, S. C.

    1991-12-01

    Thermal comfort field experiments were conducted in Singapore in both naturally ventilated highrise residential buildings and air conditioned office buildings. Each of the 818 questionnaire responses was made simultaneously with a detailed set of indoor climatic measurements, and estimates of clothing insulation and metabolic rate. Results for the air conditioned sample indicated that office buildings were overcooled, causing up to one-third of their occupants to experience cool thermal comfort sensations. These observations in air conditioned buildings were broadly consistent with the ISO, ASHRAE and Singapore indoor climatic standards. Indoor climates of the naturally ventilated apartments during the day and early evening were on average three degrees warmer than the ISO comfort standard prescriptions, but caused much less thermal discomfort than expected. Discrepancies between thermal comfort responses in apartment blocks and office buildings are discussed in terms of contemporary perceptual theory.

  12. AN IMPACT OF THE EFFICIENT FUNCTIONING OF THE VENTILATION AND AIR-CONDITIONING SYSTEM ON THERMAL COMFORT OF THE MEDICAL STAFF IN THE OPERATING ROOM

    OpenAIRE

    Tomasz Jankowski; Magdalena Młynarczyk

    2016-01-01

    Ventilation and air conditioning systems are necessary for developing proper parameters of indoor envi-ronment in operating rooms. The main task of ventilation and air conditioning in those specific areas consists in creating desirable temperature, reducing the number of microorganisms and the concen-trations of hazardous gases and substances in the air, as well as ensuring the proper direction of airflow. In Poland, indoor environment in operating rooms has to comply with the requirements se...

  13. A study on the evaluation of ventilation system suitable for outside air cooling applied in large data center for energy conservation

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Yong Il [Shinhan University, Euijungbu (Korea, Republic of)

    2016-05-15

    In developed countries, expansion of communication technology has resulted in continual increase in the construction of data centers with high-density cooling loads. Throughout a year, IT equipment installed in a data center generates large and constant cooling load. As a result, data centers may be consuming an ever-growing amount of energy. The cooling system utilizing the energy of outside air is applied universally to reduce data center energy consumption. The application of the cooling system to the outdoor air cooling system of a data center considers that temperature efficiency and ventilation performance vary depending on the type of ventilation system. The displacement and mixed ventilation method can be applied generally to a data center. The efficiency of a ventilation system depends on inside temperature or contaminant concentrations in room and outlets. This study thus aims to evaluate the ventilation performance that varies according to type of ventilation system installed in the data center. Ventilation efficiency is assessed by applying the concept of total air age and considers the fresh air ratio and age of return air. Further, temperature efficiency gained by utilizing temperature difference is used to assess causes for changes in ventilation performance.

  14. ETS levels in hospitality environments satisfying ASHRAE standard 62-1989: "ventilation for acceptable indoor air quality"

    Science.gov (United States)

    Moschandreas, D. J.; Vuilleumier, K. L.

    Prior to this study, indoor air constituent levels and ventilation rates of hospitality environments had not been measured simultaneously. This investigation measured indoor Environmental Tobacco Smoke-related (ETS-related) constituent levels in two restaurants, a billiard hall and a casino. The objective of this study was to characterize ETS-related constituent levels inside hospitality environments when the ventilation rates satisfy the requirements of the ASHRAE 62-1989 Ventilation Standard. The ventilation rate of each selected hospitality environment was measured and adjusted. The study advanced only if the requirements of the ASHRAE 62-1989 Ventilation Standard - the pertinent standard of the American Society of Heating, Refrigeration and Air Conditioning Engineers - were satisfied. The supply rates of outdoor air and occupant density were measured intermittently to assure that the ventilation rate of each facility satisfied the standard under occupied conditions. Six ETS-related constituents were measured: respirable suspended particulate (RSP) matter, fluorescent particulate matter (FPM, an estimate of the ETS particle concentrations), ultraviolet particulate matter (UVPM, a second estimate of the ETS particle concentrations), solanesol, nicotine and 3-ethenylpyridine (3-EP). ETS-related constituent levels in smoking sections, non-smoking sections and outdoors were sampled daily for eight consecutive days at each hospitality environment. This study found that the difference between the concentrations of ETS-related constituents in indoor smoking and non-smoking sections was statistically significant. Differences between indoor non-smoking sections and outdoor ETS-related constituent levels were identified but were not statistically significant. Similarly, differences between weekday and weekend evenings were identified but were not statistically significant. The difference between indoor smoking sections and outdoors was statistically significant. Most

  15. COSTEAU - preheating and cooling by means of underground collectors with water circulation - case study (Perret building at Satigny, Geneva) and generalisation; COSTEAU. Prechauffage et rafraichissement par collecteurs souterrains a eau. Etude de cas (batiment Perret a Satigny, Geneve) et generalisation

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.; Lachal, B.

    2003-07-01

    Since a couple of years, underground collectors with air circulation have been becoming increasingly popular as a simple means for preheating (at winter time) and cooling (at summer time) of outdoor air ahead of a ventilation system for well insulated buildings. This report considers underground collectors with water circulation used for similar purposes. They are connected to the ventilation system via an air/water heat exchanger. Starting from a case study - one-year detailed in-situ measurements and data analysis from an air-heated office building near Geneva, Switzerland - computerised simulations have been performed as a sensitivity analysis tool as well as to establish recommendations and sizing rules for planners, including cost considerations. In the case study it turned out that the water-circulated underground collector, which is installed right under the basement of this well insulated building, is in thermal contact with the basement. Its main function is to damp the daily temperature oscillation of the inlet ventilation air, bringing the expected thermal comfort improvement in the summer time. However, this underground collector is unable to collect seasonally stored heat from the ground. Hence, in the winter time the main preheating contribution arises from the series-connected heat-recovery unit from the exit air. Numerical simulations show that optimal sizing of underground collectors is essential, and that both the underground collector and the well insulated building as a physical system with thermal inertia have to be simultaneously considered in the optimization process. Optimization also has to include parasitic energy (electricity) needed by fans and pumps. As outdoor air inlet can never be flooded in the case of underground collectors with water circulation the sanitary risk encountered with air-circulated underground collectors does not exist for them. Initial investment cost for water-circulated underground collectors is higher than for a

  16. Comparison of Indoor Air Quality between 2 Ventilation Strategies in a Facility Housing Rhesus Macaques (Macaca mulatta).

    Science.gov (United States)

    Monts de Oca, Nicole A; Laughlin, Mitzi; Jenkins, John; Lockworth, Cynthia R; Bolton, Iris D; Brammer, David W

    2015-09-01

    Adequate indoor-air quality (IAQ)--defined by the temperature, relative humidity, and the levels of carbon dioxide, small particles, and total volatile organic compounds (TVOC)--is crucial in laboratory animal facilities. The ventilation standards for controlling these parameters are not well defined. This study assessed the effect of 2 ventilation strategies on IAQ in 2 rooms housing rhesus macaques (Macaca mulatta). We hypothesized that using a demand-controlled ventilation (DCV) system with a baseline ventilation rate of less than 3 fresh-air changes per hour (ACH) would maintain IAQ comparable to or better than the traditional constant flow rate (CFR) system at 12 fresh ACH. During a 60-d study period, each of the 2 rooms operated 30 d on DCV and 30 d on CFR ventilation. In both rooms, temperatures remained more consistently within the established setpoint during the DCV phase than during the CFR phase. Relative humidity did not differ significantly between rooms or strategies. CO₂ was lower during the CFR phase than DCV phase. Small-particle and TVOC levels were lower during CFR in the larger (3060 ft(3)) room but not the smaller (2340 ft(3)) room. During the DCV phase, the larger room was at the baseline airflow rate over 99% of the time and the smaller room over 96% of the time. The DCV strategy resulted in a baseline airflow rate of less than 3 ACH, which in turn provided acceptable IAQ over 96% of the time; higher ventilation rates were warranted only during sanitation periods.

  17. Mixing Ventilation

    DEFF Research Database (Denmark)

    Kandzia, Claudia; Kosonen, Risto; Melikov, Arsen Krikor;

    In this guidebook most of the known and used in practice methods for achieving mixing air distribution are discussed. Mixing ventilation has been applied to many different spaces providing fresh air and thermal comfort to the occupants. Today, a design engineer can choose from large selection of ...

  18. Influence of a Cooled Ceiling on Indoor Air Quality in a Displacement Ventilated Room Examined by Means of Computational Fluid Dynamics

    DEFF Research Database (Denmark)

    Brohus, Henrik

    The influence of a cooled ceiling on the air quality in a displacement ventilated room is examined by means of CFD. The objective of the study is to examine how the flow field in a displacement ventilated room is influenced when a cooled ceiling removes a major part of the total heat I9ad...

  19. An application of SPIV technique to experimental validation of the turbulence model for the air flow in the intersection of the mining face with the ventilation gallery

    Energy Technology Data Exchange (ETDEWEB)

    Jaszczur, Marek; Nowak, Remigiusz; Szmyd, Janusz [Faculty of Energy and Fuels, AGH University of Science and Technology (Poland); Branny, Marian; Karch, Michal; Wodziak, Waldemar, E-mail: marek.jaszczur@agh.edu.pl [Faculty of Mining and Geoengineering, AGH University of Science and Technology (Poland)

    2011-12-22

    This paper presents a comparison between results obtained using SPIV experimental technique and numerical simulations approach. An analysis has been performed to validate the turbulent models used in mining ventilation systems. The flow of air across the intersection of the mining face with the ventilation gallery has been examined.

  20. Removal of Particles from the Supply Air of Ventilation Systems Avoiding the Formation of Sensory Pollution Source

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2008-01-01

    substantial time in service, would mean a step forward towards finding an engineering solution to the problem. Additional measurements examined the effect of different pressure sensing techniques and several modifications of an air handling unit on the accuracy of the measurements of pressure drop over......Used ventilation filters can act as sources of strong sensory pollution. The pollutants emitted from loaded particle filters may include irritating products of chemical reactions occurring on the filter surfaces. Most likely oxidation reactions, especially those driven by ozone, seem to play...... an important role. Sensory pollutants emitted from used filters can have significant adverse impact on occupant performance. Therefore, removal of particles from the supply air of ventilation systems without the subsequent emission of pollutants into the airstream seems to be essential. Correct maintenance...

  1. Biphasic cuirass ventilation for treatment of an air leak after pneumothorax in a patient with nemaline myopathy: a case report.

    Science.gov (United States)

    Hino, Hitomi; Suzuki, Yuka; Ishii, Eiichi; Fukuda, Mitsumasa

    2016-12-01

    We describe an 11-year-old boy with nemaline myopathy who developed tension pneumothorax while undergoing noninvasive positive-pressure ventilation (NIPPV). The patient developed a persistent air leak after pleurodesis with minocycline hydrochloride and lowering of the NIPPV inspiratory pressure. He required additional respiratory support without the high airway pressures that may aggravate pneumothorax. We provided adequate respiratory support without increasing the positive airway pressure using biphasic cuirass ventilation (BCV), which moved the patient's chest wall by negative pressure. The air leak was resolved without any additional treatment. We should provide BCV for patients in whom surgery may have a risk of both extubation failure and postoperative complications before deciding on surgery.

  2. Effects of air conditioning, dehumidification and natural ventilation on indoor concentrations of {sup 222}Rn and {sup 220}Rn

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Thomas K.C.; Yu, K.N. E-mail: peter.yu@cityu.edu.hk

    2000-01-01

    A bedroom was selected for detailed measurements on {sup 220}Rn and {sup 222}Rn concentrations and environmental parameters including CO{sub 2} concentration, temperature and relative humidity. To simulate different sealing conditions, five conditions were artificially created in the sampling period of 25 consecutive days. It was concluded that natural ventilation is the most efficient way to lower the {sup 222}Rn levels, while air conditioning is the next. Dehumidification provides only a marginal reduction of {sup 222}Rn levels. The {sup 220}Rn concentrations are not affected by natural ventilation, air conditioner or dehumidification, and were all around 10 Bq m{sup -3}. There are no significant correlations between the {sup 220}Rn and {sup 222}Rn concentrations and environmental conditions such as CO{sub 2} concentrations, temperature, relative humidity and pressure.

  3. Computational fluid dynamics simulation of an earth-air heat exchanger for ventilation system

    Science.gov (United States)

    Raczkowski, Andrzej; Suchorab, Zbigniew; Czechowska-Kosacka, Aneta

    2017-07-01

    Directive 2010/31/EU (EPBD Recast) obligates European Union members to improve energetic performance of the buildings. One of the crucial standards of energy-saving buildings are the passive houses, which are characterized by annual maximum space heating below 15 kWh/(m2.a) and the use of the specific primary energy for all domestic applications (also heating, hot water production and electricity) below 120 kWh/(m2.a). To achieve this standard there should be applied the solutions based on ground energy acquisition. One of them is the earth-air heat exchanger (EAHC) for ventilation systems. The article presents numerical simulations conducted by solving partial differential equations for three dimensional heat transfer. For the simulations it was applied Computational Fluid Dynamics (CFD) technique. The efficiency of EAHC was considered under different values of external temperature during the winter period (from -24 to -8 °C). Obtained results prove linear correlation with calculations of EAHC according to standards of the Polish National Energy Conservation Agency (NAPE). The slope of regression between outlet temperatures calculated with CFD model and NAPE standards, equals 0.59 which means, that according the CFD model, the efficiency of the exchanger is lower.

  4. Risk Assessment of Heating, Ventilating, and Air-Conditioning Strategies in Low-Load Homes

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2016-02-17

    "Modern, energy efficient homes conforming to the Zero Energy Ready Home standard face the challenge of meeting high customer expectations for comfort. Traditional heating, ventilation, and air conditioning (HVAC) sizing and control strategies may be insufficient to adequately condition each zone due to unique load patterns in each room caused by a number of factors. These factors include solar heat gains, occupant-related gains, and gains associated with appliances and electronics. Because of shrinking shell loads, these intermittent factors are having an increasingly significant impact on the thermal load in each zone. Consequently, occupant comfort can be compromised. To evaluate the impact of climate and house geometry, as well as HVAC system and control strategies on comfort conditions, IBACOS analyzed the results of 99 TRNSYS multiple-zone simulations. The results of this analysis indicate that for simple-geometry and single-story plans, a single zone and thermostat can adequately condition the entire house. Demanding house geometry and houses with multiple stories require the consideration of multiple thermostats and multiple zones.

  5. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    Science.gov (United States)

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  7. Assainissement microbiologique de l'air et des systèmes de ventilation au moyen d'huiles essentielles

    OpenAIRE

    Pibiri, Marie-Cécile

    2006-01-01

    Ventilation systems often host bacteria and fungi that may be dangerous for the health of exposed people. Essential oils are one means among others to prevent microbial development. Used as a basis for many traditional therapies, these odorant plant extracts have been studied extensively in the medical domain and their effectiveness in the treatment of numerous pathologies has been demonstrated. As opposed to most antimicrobial agents currently used for air disinfection, essential oils are no...

  8. DISAIN SISTEM KENDALI MESIN AIR LEAK TEST MENGGUNAKAN SISTEM KENDALI PLC OMRON CJ2M DI HVAC (HEATING, VENTILATING, AND AIR CONDITIONING LINE 6

    Directory of Open Access Journals (Sweden)

    Syahril Ardi

    2015-03-01

    Full Text Available Pada proses produksi pembuatan komponen HVAC (Heating, Ventilating, and Air Conditioning dari perusahaan manufaktur di Indonesia, memerlukan proses pengecekan kebocoran pada bagian HVAC. Proses pengecekan ini dilakukan untuk memastikan tidak ada komponen HVAC yang bocor sebelum dikirim ke pihak pelanggan. Penelitian ini dilakukan untuk membuat system dan alat air leak test. Mesin air leak test ini menggunakan prinsip kerja differential pressure air leak test, yaitu metode yang membandingkan antara tekanan udara yang diberikan ke produk dan master produk. Pada penelitian ini, kami membuat disain mesin air leak test menggunakan sistem kendali berupa air leak tester, PLC, dan HMI. Berdasarkan kondisi dengan kapasitas produksi yang meningkat karena bertambahnya permintaan dari customer, dapat ditanggulangi dengan adanya share loading produksi dari HVAC line 4 ke line baru, yaitu HVAC line 6. Hasil yang didapat dari pengujian deteksi kebocoran produk,didapat nilai parameter kebocoran produk sebesar 2.23 ml/min.

  9. Energy Code Enforcement Training Manual : Covering the Washington State Energy Code and the Ventilation and Indoor Air Quality Code.

    Energy Technology Data Exchange (ETDEWEB)

    Washington State Energy Code Program

    1992-05-01

    This manual is designed to provide building department personnel with specific inspection and plan review skills and information on provisions of the 1991 edition of the Washington State Energy Code (WSEC). It also provides information on provisions of the new stand-alone Ventilation and Indoor Air Quality (VIAQ) Code.The intent of the WSEC is to reduce the amount of energy used by requiring energy-efficient construction. Such conservation reduces energy requirements, and, as a result, reduces the use of finite resources, such as gas or oil. Lowering energy demand helps everyone by keeping electricity costs down. (It is less expensive to use existing electrical capacity efficiently than it is to develop new and additional capacity needed to heat or cool inefficient buildings.) The new VIAQ Code (effective July, 1991) is a natural companion to the energy code. Whether energy-efficient or not, an homes have potential indoor air quality problems. Studies have shown that indoor air is often more polluted than outdoor air. The VIAQ Code provides a means of exchanging stale air for fresh, without compromising energy savings, by setting standards for a controlled ventilation system. It also offers requirements meant to prevent indoor air pollution from building products or radon.

  10. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ecton, P.A. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Beatty, J.; Verbeck, G. [Department of Chemistry, University of North Texas, Denton, TX 76203 (United States); Lakshantha, W.; Rout, B. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Perez, J.M., E-mail: jperez@unt.edu [Department of Physics, University of North Texas, Denton, TX 76203 (United States)

    2016-11-30

    Highlights: • Preheating SWCNTs in situ before irradiation prevents an increase in the D peak. • Preheated SWCNTs exposed to air or gases before irradiation show an increase in D peak. • The increase in D peak is not due to irradiation-induced chemisorption of adsorbates. • The effects are more significant for small diameter SWCNTs. • The increase in D peak is attributed to defects that increase inter-tube interactions. - Abstract: We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  11. Evaluation of Heating, Ventilation, and Air conditioning (HVAC System Performance in an Administrative Building in Tehran (Iran

    Directory of Open Access Journals (Sweden)

    H. Mari Oriyad

    2014-09-01

    Full Text Available Introduction: One of the factors influencing on indoor air quality of the buildings is performance of HVAC (heating, ventilation, and air conditioning systems. These systems supply clean and odorless air, with temperature, humidity, and air velocity within comfort ranges for the residents. The aim of this study was to evaluate performance HVAC system in an administrative building in Tehran. .Material and Method: A questionnaire, developed in their research was used to assess the building occupants’ perception about the performance of HVAC system. To evaluate the performance of HVAC systems, air velocities were measured in the diffusers using a thermal anemometer. Moreover, CO2 concentration, air temperature and relative humidity were measured in the whole floors of the building. Air distribution inside the building was evaluated using smoke test. .Results: Most of the studied people complained about the direction of airflow, thermal conditions and cigarette odor. The highest level of carbon dioxide was measured at 930 ppm inside the restaurant. The maximum and minimum air temperatures and relative humidity were measured 28.3-13.8° C and 28.4-23% respectively. Smoke test showed that the air distribution/direction wasn’t suitable in one third of air diffusers. .Conclusion: Improper air distribution / direction was the main problem with the studied HVAC system which could be corrected by adjusting and balancing of the system.

  12. Effectiveness of heating, ventilation and air conditioning system with HEPA filter unit on indoor air quality and asthmatic children's health

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Raja, Suresh; Ferro, Andrea R.; Jaques, Peter A.; Hopke, Philip K. [Clarkson University, 8 Clarkson Avenue, Center for Air Resources Engineering and Science, Potsdam, NY 13699 (United States); Gressani, Cheryl; Wetzel, Larry E. [Air Innovations, Inc, 7000 Performance Drive, North Syracuse, NY 13212 (United States)

    2010-02-15

    Poor indoor air quality has been linked to the exacerbation of asthma symptoms in children. Because people spend most of their time indoors, improving indoor air quality may provide some relief to asthma sufferers. A study was conducted to assess whether operating an air cleaning/ventilating unit (HEPAiRx {sup registered}) in a child's bedroom can improve his/her respiratory health. Thirty children diagnosed with asthma were randomly split into two groups. For the first six weeks, group A had the air cleaning/ventilating unit (HEPAiRx {sup registered}) running in the bedrooms of the participants and group B did not; for the second six weeks, both groups had the cleaners running in the bedrooms; and, for the final six weeks, group A turned the cleaners off and group B kept theirs running. Indoor air quality parameters, including temperature, relative humidity, particulate matter (PM 0.5-10 {mu}m), carbon monoxide, carbon dioxide and total volatile organic compound (TVOC) concentrations, were monitored in each bedroom using an AirAdvice indoor air quality multi-meter. As a measure of pulmonary inflammation, exhaled breath condensate (EBC) was collected every sixth day and analyzed for nitrate and pH. Peak expiratory flow (PEF) was also measured. PM and TVOC concentrations decreased with operation of the HEPAiRx an average of 72% and 59%, respectively. The EBC nitrate concentrations decreased significantly and the EBC pH and PEF values increased significantly with operation of the unit (p < 0.001 when comparing on/off sample means). These results indicate that air cleaning in combination with ventilation can effectively reduce symptoms for asthma sufferers. (author)

  13. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, William J. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trinity College Dublin, Dublin (Ireland); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-19

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector's energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level. The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.

  14. Final Report Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores in California. Predicted indoor air quality and energy consumption using a matrix of ventilation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Apte, Michael G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sohn, Michael D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dutton, Spencer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Berkeley, Pam M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spears, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-02-01

    Through mass-balance modeling of various ventilation scenarios that might satisfy the ASHRAE 62.1 Indoor Air Quality (IAQ) Procedure, we estimate indoor concentrations of contaminants of concern (COCs) in California “big box” stores, compare estimates to available thresholds, and for selected scenarios estimate differences in energy consumption. Findings are intended to inform decisions on adding performance-based approaches to ventilation rate (VR) standards for commercial buildings. Using multi-zone mass-balance models and available contaminant source rates, we estimated concentrations of 34 COCs for multiple ventilation scenarios: VRmin (0.04 cfm/ft2 ), VRmax (0.24 cfm/ft2 ), and VRmid (0.14 cfm/ft2 ). We compared COC concentrations with available health, olfactory, and irritant thresholds. We estimated building energy consumption at different VRs using a previously developed EnergyPlus model. VRmax did control all contaminants adequately, but VRmin did not, and VRmid did so only marginally. Air cleaning and local ventilation near strong sources both showed promise. Higher VRs increased indoor concentrations of outdoor air pollutants. Lowering VRs in big box stores in California from VRmax to VRmid would reduce total energy use by an estimated 6.6% and energy costs by 2.5%. Reducing the required VRs in California’s big box stores could reduce energy use and costs, but poses challenges for health and comfort of occupants. Source removal, air cleaning, and local ventilation may be needed at reduced VRs, and even at current recommended VRs. Also, alternative ventilation strategies taking climate and season into account in ventilation schedules may provide greater energy cost savings than constant ventilation rates, while improving IAQ.

  15. Can we establish relationship between outdoor air ventilation and health based on the published epidemiological data?

    DEFF Research Database (Denmark)

    Carrer, Paolo; Wargocki, Pawel; Fanetti, Annaclara

    2015-01-01

    from 6-7 L/s per person, which were the lowest ventilation rates, at which no effects on some health outcomes were observed in field studies, until 25-40 L/s per person, which were in some studies the highest ventilation rates needed so no effects on health outcomes were seen. The actual contaminant...

  16. The impact of air pollution from used ventilation filters on human comfort and health

    DEFF Research Database (Denmark)

    Clausen, Geo; Alm, O.; Fanger, Povl Ole

    2002-01-01

    The comfort and health of 30 women was studied during 4 hours´ exposure in an experimental room with either a used or a new filter present in the ventilation system. All other environmental parameters were kept constant. The presence of the used filter in the ventilation system had a significant...

  17. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    with conventional ventilation systems (mixing or displacement ventilation), diffuse ceiling ventilation can significantly reduce or even eliminate draught risk in the occupied zone. Moreover, this ventilation system presents a promising opportunity for energy saving, because of the low pressure loss, extended free......Diffuse ceiling ventilation is an innovative ventilation concept where the suspended ceiling serves as an air diffuser to supply fresh air into the room. Due to the large opening area, air is delivered to the room with very low velocity and no fixed direction, therefore the name ‘diffuse’. Compared......-cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...

  18. Ventilation and Air Conditioning Design and Lampblack Purification in Kitchen%厨房的通风空调设计与油烟的净化

    Institute of Scientific and Technical Information of China (English)

    石建中

    2012-01-01

    The article discussed system form,ventilation volume,airflow structure,kitchen air supply,fire smoke,exhaust purification in kitchen ventilation and air conditioning design.%主要论述了厨房的通风空调设计中系统形式、通风量、气流组织、厨房补风、防火排烟、排风净化等方面的问题。

  19. Novel approach for evaluation of air change rate in naturally ventilated occupied spaces based on metabolic CO2 time variation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Markov, Detelin G.

    2014-01-01

    at low rate. This paper describes a new approach for ACR evaluation in naturally ventilated occupied spaces. Actual metabolic CO2 time variation record in an interval of time is compared with the computed variation of metabolic CO2 for the same time interval under reference conditions: sleeping occupants......, air-tight space, constant indoor pressure and temperature. The proposed approach for ACR evaluation can be applied to time intervals with any length, even with varying parameters of both indoor and outdoor air, in which metabolic CO2 generation rate is known and constant. This approach makes possible...

  20. Exposure to Exhaled Air from a Sick Occupant in a Two-Bed Hospital Room with Mixing Ventilation: Effect of Posture of Doctor and Air Change Rate

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Barova, Mariya

    2013-01-01

    Full-scale measurements were performed in a climate chamber set as a two-bed hospital room, ventilated at 3, 6 and 12 ACH with overhead mixing ventilation. Air temperature was kept constant at 22 °C. Two breathing thermal manikins were used to mimic a sick patient lying on one side in one...... of the beds and a doctor. A thermal dummy mimicked an exposed patient lying in the second bed. The doctor either stood up or sat in a chair 0.55 m facing the sick patient. The ‘sick patient’ was exhaling through the mouth and inhaling from the nose. Tracer gas (R 134A) was mixed with the exhaled air to mimic...

  1. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    Science.gov (United States)

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

  2. Impact of Air Distribution on Heat Transfer during Night-Time Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Artmann, Nikolai; Jensen, Rasmus Lund

    2009-01-01

    Passive cooling by night-time ventilation is seen as a promising approach for energy efficient cooling of buildings. However, uncertainties in prediction of cooling potential and consequenses for thermal comfort restrain architects and engineers from applying this technique. Heat transfer...... at internal room surfaces determines the performance of night-time ventilation. In order to improve predictability, heat transfer mechanism in case of either mixing or displacement ventilation has been investigated in a full scale test room with an exposed ceiling as the dominating thermal mass. The influence...

  3. Mechanical ventilation with heat recovery in arctic climate

    DEFF Research Database (Denmark)

    Kragh, Jesper; Svendsen, Svend

    2005-01-01

    Mechanical ventilations systems with highly effective heat recovery units in arctic climate have problems with condensing water from the extracted humid indoor air. If the condensing water freezes to ice in the heat recovery unit, the airflow rate will quickly diminish due to the increasing...... pressure drop. Preheating the inlet air (outdoor air) to a temperature just above 0ºC is typically used to solve the problem. To minimize the energy cost, a more efficient solution to the problem is therefore desirable. In this project a new design of a heat recovery unit has been developed to the low......-energy house in Sisimiut, which is capable of continuously defrosting itself. The disadvantage of the unit is that it is quite big compared with other units. In this paper the new heat recovery unit is described and laboratory measurements are presented showing that the unit is capable of continuously...

  4. Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The potential for improving occupants' thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied...... of the results obtained reveal improved acceptability of perceived air quality and improved thermal sensation with PV-UFAD in comparison with the reference case of UFAD alone or mixing ventilation with ceiling supply diffuser. The local thermal sensation at the feet was also improved when warmer UFAD supply air...

  5. Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

    Science.gov (United States)

    This letter is to brings attention several concerns that the Agency has regarding the use of sanitizer and/or disinfectant products, and other types of antimicrobial products, to treat the surfaces of heating, ventilation

  6. Study on heat collector of the solar system utilizing outdoor air. Experimental results in cases of cold and warm regions; Gaiki donyushiki solar system no shunetsubu ni kansuru kenkyu. Kanreichi to ondanchi ni okeru shunetsu jikken to kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Komano, S.; Ebara, Y. [OM Solar Association, Shizuoka (Japan); Wada, H. [Wada Building Constructors Co. Ltd., Hokkaido (Japan)

    1996-10-27

    An experiment on heat collection was made in the heat collector of a solar system utilizing outdoor air in cold and warm regions. In this system, outdoor air is heated by the air circulation layer on the roof exposed to solar radiation. The heated air is supplied to the object space for heating and ventilation. In the experiment in a cold region, the heat collection characteristics can be adjusted by putting a baffle plate in the air duct according to the experiment of a glass heat collector. The heat collecting air layer on only the iron roof may leak or freeze in the region subject to coldness or heavy snowfall. Therefore, preheat forms the space of a garret, and the preheat temperature comparatively becomes low. The data in which the heat collection characteristics can be adjusted using only a glass heat collector is required corresponding to the regional situation. In the experiment in a warm region, an experiment was made inclusive of the preheat for which outdoor air is absorbed at the eaves. As a result, the heat collection characteristics of preheat were improved. Moreover, a heat collection temperature of about 60{degree}C was obtained on the heat collection surface including the preheat. 1 ref., 12 figs., 3 tabs.

  7. Fuel preheater for diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Crossett, J.J.; Crossett, M.C.

    1987-10-13

    A unit for preheating fuel for diesel engines is described having an engine coolant system and a lubrication system utilizing a flowable lubricant. The unit comprises a housing providing a fluid-tight enclosure, a heat exchange coil positioned in and spaced above the bottom of the enclosure and having loops providing a continuous path for the flow of the fuel to be heated. The heat exchange coil has at least one foot of length for each 25 cubic inches of volume of the enclosure and a diesel fuel outlet in the housing connected to one end of the heat exchange coil, a diesel fuel outlet in the housing and connected to the other end of the heat exchange coil, an inlet in the housing for connection of the interior of the enclosure surrounding the coil to a source of a hot heat exchange medium in a diesel engine so as to provide a source of heat for heating the heat exchange coil. An outlet near the top of the housing provides for return of the heat exchange medium to a diesel engine, and spray tube means extend horizontally from the inlet for the heat exchange medium and along the bottom of the housing beneath substantially the entire length of the heat exchange coil. The means have upwardly directed openings to provide for discharge of the heat exchange medium toward the coil and agitation of the heat exchange medium in the enclosure around and over the heat exchange coil.

  8. Air temperature and CO{sub 2} variations in a naturally ventilated classroom under a Nordic climate

    Energy Technology Data Exchange (ETDEWEB)

    Celis Mercier, S.; Potvin, A. [Laval Univ., Quebec City, PQ (Canada). School of Architecture; Tardif, M. [Sustainable Buildings and Communities, Ottawa, ON (Canada)

    2009-07-01

    This paper presented preliminary results of the first stage of an ongoing passive cooling pre-design evaluation for the refurbishment of a primary school in Ste-Marie-de-Beauce, Quebec. The 1950's building did not have any mechanical systems apart from the central hot-water heating system. The viability of passive cooling and natural ventilation was evaluated by considering whether the surrounding outside conditions were favourable to passive cooling and natural ventilation and whether the the building envelope was optimized to minimize solar gain into the space. The study also evaluated the effectiveness of window operation in controlling a classroom thermal environment and indoor air quality. Field measurements and questionnaires were collected in the fall of 2008. A systemic approach integrating acoustic, thermal, visual and olfactory ambiences was proposed. 17 refs., 13 figs.

  9. Exposure of health care workers and occupants to coughed air in a hospital room with displacement air distribution: impact of ventilation rate and distance from coughing patient

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Bolashikov, Zhecho Dimitrov; Kostadinov, Kamen

    The exposure of a doctor and a second patient to coughed air by an infected patient was studied in a simulated two-bed hospital patient room. The air temperature in the room, ventilated at two air change rates (3 h-1 and 6 h-1) was kept 22 oC. Thermal manikin with realistic body shape and surface...... temperature distribution was used as the doctor standing 0.55, 1.1 or 2.8 m downstream the cough. A coughing thermal dummy, lying in one bed and a second thermal manikin in the other bed (1.3 m away), were used as the “sick” and the “exposed” patients. The cough consisted of 100% CO2. The doctor...... hospital standards as minimum ventilation rate in hospital patient rooms, resulted in elevated exposure to coughed air for the doctor, suggesting increased risk from airborne cross-infection. Displacement air distribution does not reduce the risk from cross-infection....

  10. Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings

    Science.gov (United States)

    Kamal, Rajeev

    Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times. Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings: 1. Use of gas heat pumps in place of electric heat pumps, and 2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice. The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected. The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at

  11. Characterization of preheated and non-preheated HY-80 steel weldments by transmission electron microscopy

    OpenAIRE

    Clark, David Richard

    1983-01-01

    Approved for public release; distribution in unlimited. Preheating HY-80 steel weldments is standard procedure, but it is an expensive and time consuming step in the fabrication of hull structures. The microstructures and hardness profiles of both a preheated (250 F--121 C) and a non-preheated (32 F--0 C) HY-80 steel weldment were studied to provide information and allow comparisons of the microstructural transformations that occur in the heat affected zone during shielded metal arc weldin...

  12. Integrated analysis of numerical weather prediction and computational fluid dynamics for estimating cross-ventilation effects on inhaled air quality inside a factory

    Science.gov (United States)

    Murga, Alicia; Sano, Yusuke; Kawamoto, Yoichi; Ito, Kazuhide

    2017-10-01

    Mechanical and passive ventilation strategies directly impact indoor air quality. Passive ventilation has recently become widespread owing to its ability to reduce energy demand in buildings, such as the case of natural or cross ventilation. To understand the effect of natural ventilation on indoor environmental quality, outdoor-indoor flow paths need to be analyzed as functions of urban atmospheric conditions, topology of the built environment, and indoor conditions. Wind-driven natural ventilation (e.g., cross ventilation) can be calculated through the wind pressure coefficient distributions of outdoor wall surfaces and openings of a building, allowing the study of indoor air parameters and airborne contaminant concentrations. Variations in outside parameters will directly impact indoor air quality and residents' health. Numerical modeling can contribute to comprehend these various parameters because it allows full control of boundary conditions and sampling points. In this study, numerical weather prediction modeling was used to calculate wind profiles/distributions at the atmospheric scale, and computational fluid dynamics was used to model detailed urban and indoor flows, which were then integrated into a dynamic downscaling analysis to predict specific urban wind parameters from the atmospheric to built-environment scale. Wind velocity and contaminant concentration distributions inside a factory building were analyzed to assess the quality of the human working environment by using a computer simulated person. The impact of cross ventilation flows and its variations on local average contaminant concentration around a factory worker, and inhaled contaminant dose, were then discussed.

  13. Dynamics of Symmetry Breaking and Tachyonic Preheating

    CERN Document Server

    Felder, G; Greene, P B; Kofman, L A; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Garcia-Bellido, Juan; Greene, Patrick B.; Kofman, Lev; Linde, Andrei; Tkachev, Igor

    2001-01-01

    We reconsider the old problem of the dynamics of spontaneous symmetry breaking using 3d lattice simulations, and develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that symmetry breaking typically completes within a single oscillation of the field distribution as it rolls towards the minimum of its effective potential. As an application of this theory we consider preheating in the hybrid inflation scenario, including SUSY-motivated F-term and D-term inflationary models. We show that preheating in hybrid inflation is typically tachyonic and the stage of oscillations of a homogeneous component of the scalar fields driving inflation ends after a single oscillation. Our results may also be relevant for the theory of the formation of disoriented chiral condensates in heavy ion collisions.

  14. Preheating after Small-Field Inflation

    CERN Document Server

    Brax, Philippe; Mariadassou, Sophie

    2010-01-01

    Whereas preheating after chaotic and hybrid inflation models has been abundantly studied in the literature, preheating in small field inflation models, where the curvature of the inflaton potential is negative during inflation, remains less explored. In these models, a tachyonic instability at the end of inflation leads to a succession of exponentially large increases and \\emph{decreases} of the inflaton fluctuations as the inflaton condensate oscillates around the minimum of its potential. The net effect is a competition between low-momentum modes which grow and decrease significantly, and modes with higher momenta which grow less but also decrease less. We develop an analytical description of this process, which is analogous to the quantum mechanical problem of tunneling through a volcano-shaped potential. Depending on the parameters, preheating may be so efficient that it completes in less than one oscillation of the inflaton condensate. Preheating after small field inflation may also be followed by a long...

  15. Restoring the sting to metric preheating

    CERN Document Server

    Bassett, B A; Maartens, R; Kaiser, D I; Bassett, Bruce A.; Gordon, Chris; Maartens, Roy; Kaiser, David I.

    2000-01-01

    The relative growth of field and metric perturbations during preheating is sensitive to initial conditions set in the preceding inflationary phase. Recent work suggests this may protect super-Hubble metric perturbations from resonant amplification during preheating. We show that this possibility is fragile and extremely sensitive to the specific form of the interactions between the inflaton and other fields. The suppression is naturally absent in two classes of preheating in which either (1) the critical points (hence the vacua) of the effective potential during inflation are deformed away from the origin, or (2) the effective masses of fields during inflation are small but during preheating are large. Unlike the simple toy model of a g^2 \\phi^2 \\chi^2 coupling, most realistic particle physics models contain these other features. Moreover, they generically lead to both adiabatic and isocurvature modes and non-Gaussian scars on super-Hubble scales. Large-scale coherent magnetic fields may also appear naturally...

  16. Personalized ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2004-01-01

    existing knowledge on performance of personalized ventilation (PV) and on human response to it. The airflow interaction in the vicinity of the human body is analyzed and its impact on thermal comfort and inhaled air quality is discussed together with control strategies and the application of PV in practice...

  17. Design and optimization of personalized ventilation for overall improvement of thermal comfort, air quality, and energy efficiency

    Science.gov (United States)

    Metzger, Ian Dominic

    This paper presents a simple and repeatable CFD-based method that can accurately predict the optimal operating conditions of personalized ventilation systems. In contrast to previous studies, the optimal performance of the PV system includes the influences of various operation characteristics (supply air velocity, PV flow rate, PV temperature, PV distance from face, turbulence intensity, relative humidity, central system flow rate, central system temperature, central system type, and PV on/off operation) on three critical performance factors: thermal comfort, indoor air quality, and energy savings. This method is able to predict more achievable and comprehensive operating performance of PV systems. It is found for the computer perimeter grill air terminal device that supply temperatures, central flow rate, and PV flow rate are the most influential factors on performance in terms of thermal comfort, IAQ, and energy. Using the Taguchi design of experiment and optimal performance prediction method, the computer perimeter grill personalized ventilation system is optimized in conjunction with under-floor and overhead central systems, separately.

  18. Ventilation and air conditioning systems in maritime productions units; Panorama dos sistemas de VAC em unidades maritimas de producao

    Energy Technology Data Exchange (ETDEWEB)

    Guedes, Fernando Pedrosa; Sztajnbok, Ernani Luis [PETROBRAS, Rio de Janeiro, RJ (Brazil); Padua, Carlos Eduardo Dantas de; Passos, Alfredo Silveira [DUOVAC Engenharia Ltda. (Brazil)

    2004-07-01

    In an Offshore Stationary Production Unit (SPU), the adequate project of the Ventilation and Air Conditioning (VAC) System is not only a thermal comfort requirement but part of the essential safety services of the installation and complement for area classification requirements associated with electrical equipment. The VAC installations are sometimes the object of complaints by onboard team. Problems such as unsatisfactory system performance, high noise levels in the accommodation quarters, offices and other areas and the discomfort caused by unbalanced ventilation and air conditioning systems, are some of the most frequent complaints. Air Conditioning systems are classified as Direct and Indirect Expansion. Decentralized systems with Indirect Expansion has been adopted in PETROBRAS projects. This conception is not used in VAC Systems for platforms installed in North Sea, where the use of Centralized Systems with Direct Expansion are more common. The objective of this work is to compare the VAC conception projects, analyzing their advantages and disadvantages . The evaluation of VAC System in PETROBRAS project, and their steps in SPU development, is also scope of this paper. (author)

  19. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Commercial Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-09-01

    This report covers an assessment of 182 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. commercial buildings to identify and provide analysis on 17 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, description of technical maturity, description of non-energy benefits, description of current barriers for market adoption, and description of the technology’s applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  20. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Residential Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Goetzler, William [Navigant Consulting, Inc., Burlington, MA (United States); Zogg, Robert [Navigant Consulting, Inc., Burlington, MA (United States); Young, Jim [Navigant Consulting, Inc., Burlington, MA (United States); Schmidt, Justin [Navigant Consulting, Inc., Burlington, MA (United States)

    2012-10-01

    This report is an assessment of 135 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. residential buildings to identify and provide analysis on 19 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, descriptions of technical maturity, descriptions of non-energy benefits, descriptions of current barriers for market adoption, and descriptions of the technology's applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  1. Design of a mobile laboratory for ventilation studies and indoor air pollution monitoring. [Residences and commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Berk, J.V.; Hollowell, C.D.; Lin, C.I.; Pepper, J.H.

    1978-04-01

    A mobile laboratory for research and development studies of ventilation requirements and energy utilization in residential and commercial buildings was designed and fabricated. The mobile laboratory contains sampling, calibrating, and monitoring systems to measure the concentration of CO, CO/sub 2/, NO, NO/sub 2/, NO/sub x/, O/sub 3/, and SO/sub 2/, and infiltration rates can be monitored continuously using a tracer gas system in which the tracer is injected into the room, mixed with room air, and monitored.

  2. Comparison of a Constant Air Volume (CAV) and a Demand Controlled Ventilation (DCV) System in a Residential Building

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus

    2008-01-01

    The aim of this paper was to compare the indoor climate and the energy performance of a Constant Air Volume (CAV) system of 0.5h-1 with a Demand Controlled Ventilation (DCV) system controlled by occupancy and relative humidity for a studio apartment. Furthermore the impact of building materials...... hygroscopic properties on indoor climate and energy consumption was investigated for the two systems. Dynamic simulations of the studio apartment were carried out in the program WUFI+ with weather data from Copenhagen including outside temperature end relative humidity. For the non-hygroscopic case...

  3. The conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK

    Directory of Open Access Journals (Sweden)

    V.M. Yakubson

    2014-04-01

    Full Text Available On April, 11th, in Lenexpo the XVI conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK “Effective HVAC and Heat Supply Systems” took place. There were a lot of presentations of new equipment for building systems and networks. All these reports were dedicated to the ways to make buildings more comfortable for people, to increase the energy efficiency, to reduce expenses and to improve the production efficiency. But besides the specific equipment, there were some reports dedicated to more general problems in design, installation and maintenance of building systems and networks

  4. Ventilation Model

    Energy Technology Data Exchange (ETDEWEB)

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to

  5. Double-diffusive mixed convection in the slot ventilated enclosure with different arrangements of supplying air flow ports

    Directory of Open Access Journals (Sweden)

    Heng-Sheng Cheng

    2015-03-01

    Full Text Available Steady double-diffusive mixed convection in an enclosure with side venting and discrete heat and contaminant sources is numerically studied under supplying upside and returning downside (STRB mode and returning upside and supplying downside mode (RTSB, respectively. The parameters governing the fluid flow include the Grashof number Gr (102–106, Reynolds number Re (100–500, supplying or returning distance H 1/HT (0–2, Prandtl number Pr (0.7, buoyancy ratio N, and Schmidt number Sc. Effects of Gr, Re, and H 1/HT on the flow patterns, thermal, and species transports were numerically investigated concerning STRB and RTSB modes. Fluid flow, heat, and species transports in the enclosure are visualized and analyzed by the contours of stream function, heat function, and mass function, respectively. Air age was also presented to evaluate the freshness of the enclosed fluid. Averaged Nusselt number of the heat source and Sherwood number of the contaminant source are power-law correlated with Gr, Re, and H 1/HT for two ventilation modes, respectively. The correlations demonstrate that the ratio of averaged Nusselt number to Sherwood number was approximately approaching unity, independent of ventilation modes and values of H 1/HT . This investigation could benefit the future design of room ventilation and thermal removals from the electronic chips.

  6. Dispersal of Exhaled Air and Personal Exposure in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Bjørn, Erik; Nielsen, Peter Vilhelm

    2002-01-01

    The influence of the human exhalation on flow fields, contaminant distributions, and personal exposures in displacement ventilated rooms is studied together with the effects of physical movement. Experiments are conducted in full-scale test rooms with life-sized breathing thermal manikins...... of the exhalation flow is no acute problem in most normal ventilation applications. However, exhalation and local effects caused by movement may be worth considering if one wishes to contain contaminants in certain areas, as in the case of tobacco smoking, in hospitals and clinics, or in certain industries....

  7. Design of a mobile laboratory for ventilation studies and indoor air pollution monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Berk, J.V.; Hollowell, C.D.; Lin, C.I.; Pepper, J.H.

    1978-04-01

    The design and fabrication of a mobile laboratory for research and development studies of ventilation requirements and energy utilization in residential and commercial buildings are described. Functionality, flexibility, and versatility have been stressed without sacrificing appearance and operator convenience. It is believed that modifications of and additions to the mobile laboratory (such as adding the capability to monitor building energy flow) can be made with a minimum of inconvenience. The studies being performed will provide data needed for the establishment of energy efficient ventilation standards.

  8. Dynamic model of counter flow air to air heat exchanger for comfort ventilation with condensation and frost formation

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Rose, Jørgen; Kragh, Jesper

    2009-01-01

    In cold climates heat recovery in the ventilation system is essential to reduce heating energy demand. Condensation and freezing occur often in efficient heat exchangers used in cold climates. To develop efficient heat exchangers and defrosting strategies for cold climates, heat and mass transfer...

  9. Pre-heating mitigates composite degradation

    Directory of Open Access Journals (Sweden)

    Jessika Calixto da SILVA

    2015-12-01

    Full Text Available ABSTRACT Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS. Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm and the composites Durafill VS (Heraeus Kulzer, Z-250 (3M/ESPE, and Z-350 (3M/ESPE, cured at 25°C (no pre-heating or 60°C (pre-heating. Specimens were stored sequentially in the following solutions: 1 water for 7 days (60°C, plus 0.1 N sodium hydroxide (NaOH for 14 days (60°C; 2 50% silver nitrate (AgNO3 for 10 days (60°C. Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey’s tests (α=5%. Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (p<0.05. After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05. There was a lower penetration of silver in pre-heated specimens (p<0.05. Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  10. Optimization of air quantity regulation in mine ventilation networks using the improved differential evolution algorithm and critical path method

    Institute of Scientific and Technical Information of China (English)

    Chen Kaiyan; Si Junhong; Zhou Fubao; Zhang Renwei; Shao He; Zhao Hongmei

    2015-01-01

    In mine ventilation networks, the reasonable airflow distribution is very important for the production safety and economy. Three basic problems of the natural, full-controlled and semi-controlled splitting were reviewed in the paper. Aiming at the high difficulty semi-controlled splitting problem, the general nonlinear multi-objectives optimization mathematical model with constraints was established based on the theory of mine ventilation networks. A new algorithm, which combined the improved differential evaluation and the critical path method (CPM) based on the multivariable separate solution strategy, was put forward to search for the global optimal solution more efficiently. In each step of evolution, the feasible solutions of air quantity distribution are firstly produced by the improved differential evolu-tion algorithm, and then the optimal solutions of regulator pressure drop are obtained by the CPM. Through finite steps iterations, the optimal solution can be given. In this new algorithm, the population of feasible solutions were sorted and grouped for enhancing the global search ability and the individuals in general group were randomly initialized for keeping diversity. Meanwhile, the individual neighbor-hood in the fine group which may be closely to the optimal solutions were searched locally and slightly for achieving a balance between global searching and local searching, thus improving the convergence rate. The computer program was developed based on this method. Finally, the two ventilation networks with single-fan and multi-fans were solved. The results show that this algorithm has advantages of high effectiveness, fast convergence, good robustness and flexibility. This computer program could be used to solve large-scale generalized ventilation networks optimization problem in the future.

  11. Use of Recirculating Ventilation With Dust Filtration to Improve Wintertime Air Quality in a Swine Farrowing Room.

    Science.gov (United States)

    Anthony, T Renée; Altmaier, Ralph; Jones, Samuel; Gassman, Rich; Park, Jae Hong; Peters, Thomas M

    2015-01-01

    The performance of a recirculating ventilation system with dust filtration was evaluated to determine its effectiveness to improve the air quality in a swine farrowing room of a concentrated animal feeding operation (CAFO). Air was exhausted from the room (0.47 m(3) sec(-1); 1000 cfm), treated with a filtration unit (Shaker-Dust Collector), and returned to the farrowing room to reduce dust concentrations while retaining heat necessary for livestock health. The air quality in the room was assessed over a winter, during which time limited fresh air is traditionally brought into the building. Over the study period, dust concentrations ranged from 0.005-0.31 mg m(-3) (respirable) and 0.17-2.09 mg m(-3) (inhalable). In-room dust concentrations were reduced (41% for respirable and 33% for inhalable) with the system in operation, while gas concentrations (ammonia [NH3], hydrogen sulfide [H2S], carbon monoxide [CO], carbon dioxide [CO2]) were unchanged. The position of the exhaust and return air systems provided reasonably uniform contaminant distributions, although the respirable dust concentrations nearest one of the exhaust ducts was statistically higher than other locations in the room, with differences averaging only 0.05 mg m(-3). Throughout the study, CO2 concentrations consistently exceeded 1540 ppm (industry recommendations) and on eight of the 18 study days it exceeded 2500 ppm (50% of the ACGIH TLV), with significantly higher concentrations near a door to a temperature-controlled hallway that was typically often left open. Alternative heaters are recommended to reduce CO2 concentrations in the room. Contaminant concentrations were modeled using production and environmental factors, with NH3 related to the number of sow in the room and outdoor temperatures and CO2 related to the number of piglets and outdoor temperatures. The recirculating ventilation system provided dust reduction without increasing concentrations of hazardous gases.

  12. Air quality in a simulated office environment as a result of reducing pollution sources and increasing ventilation

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Bako-Biro, Zsolt; Clausen, Geo

    2002-01-01

    Air quality was studied in an office space classified as low-polluting and ventilated with outdoor air at a rate of 1 h-1. The pollution load in the space was changed by introducing or removing common building-related indoor pollution sources (linoleum, sealant and wooden shelves with books...... and paper documents) so that the space could no longer be classified as low-polluting. The outdoor air supply rate in the office was altered from 1 to 3 h-1 (0.83 and 2.5 l/s per m2 floor, respectively) when sources were present and absent. Air temperature of 23 deg.C, relative humidity of 50% and noise...... level of 35 dB(A) remained unchanged. Under each of the four conditions of air quality in the office, concentrations of volatile organic compounds (VOCs) were measured and perceived air quality was assessed by a panel of 30 female subjects. Removing the sources reduced the chemical and sensory pollution...

  13. Investigation on preheating process in SLS machine

    Institute of Scientific and Technical Information of China (English)

    李湘生; 史玉升; 莫健华; 黄树槐

    2001-01-01

    Selective laser sintering (SLS) is an important Rapid Prototyping method because its wide range of materials. The powder is fused and processed into a part because it is heated in the process. Preheating of powder on the surface of powder bed is a one important process which is a guarantee by which parts can be successfully fabricated and influences accuracy of parts fabricated in SLS technology. The uniformity of temperature on powder bed influences accuracy and performance of parts. It is necessary to understand the influences of the parameters of preheating set on uniformity of temperature on surface of powder bed. This paper analyzes general preheating process of irradiator for the preheating of powder on the surface of powder bed during SLS processing,and investigates influences of the flux density on the temperature field on the top surface of powder bed. The models of distribution of flux density and the distribution of surface temperature of powder bed are presented.The result predicted according to the models is reasonably consistent with experimental result. This model plays important role in design of preheating set and control of SLS processing. It is concluded that the uniformity of temperature field on the powder bed is determined mostly by the geometry of heating component and its fix location and the flux density is inverse proportional to the highness.

  14. Waste heat recovery at the glass industry with the intervention of batch and cullet preheating

    Directory of Open Access Journals (Sweden)

    Dolianitis Ioannis

    2016-01-01

    Full Text Available A promising option to reduce the specific energy consumption and CO2 emissions at a conventional natural gas fired container glass furnace deals with the advanced utilization of the exhaust gases downstream the air regenerators by means of batch and cullet preheating. A 3-dimensional computational model that simulates this process using mass and heat transfer equations inside a preheater has been developed. A case study for an efficient small-sized container glass furnace is presented dealing with the investigation of the impact of different operating and design configurations on specific energy consumption, CO2 emissions, flue gas energy recovery, batch temperature and preheater efficiency. In specific, the effect of various parameters is studied, including the preheater’s dimensions, flue gas temperature, batch moisture content, glass pull, combustion air excess and cullet fraction. Expected energy savings margin is estimated to 12-15%.

  15. Study of the ventilation at ATLAS cavern UX15 air velocity and temperature around the muon chambers

    CERN Document Server

    Vigo-Castellví, E

    2000-01-01

    The Muon Chambers of ATLAS detector cannot work under temperature differences between two opposed faces above 3 K. In addition, a low velocity of the air around the Muon Chambers is essential to avoid vibration problems. The CV group at the ST division is involved in an airflow simulation inside UX15 cavern to check air temperature and velocity profiles around the ATLAS Muon Chambers. In this paper, the status and the content of the performed theoretical studies will be explained. Three simulation models, which helped to understand the Muon Spectrometer thermal environment and the efficiency of the ventilation system at ATLAS cavern, will be presented. Besides, it will be shown how these studies support the proposal of a deeper individual Muon Chamber study.

  16. Simulations of the impacts of building height layout on air quality in natural-ventilated rooms around street canyons.

    Science.gov (United States)

    Yang, Fang; Zhong, Ke; Chen, Yonghang; Kang, Yanming

    2017-08-30

    Numerical simulations were conducted to investigate the effects of building height ratio (i.e., HR, the height ratio of the upstream building to the downstream building) on the air quality in buildings beside street canyons, and both regular and staggered canyons were considered for the simulations. The results show that the building height ratio affects not only the ventilation fluxes of the rooms in the downstream building but also the pollutant concentrations around the building. The parameter, outdoor effective source intensity of a room, is then proposed to calculate the amount of vehicular pollutants that enters into building rooms. Smaller value of this parameter indicates less pollutant enters the room. The numerical results reveal that HRs from 2/7 to 7/2 are the favorable height ratios for the regular canyons, as they obtain smaller values than the other cases. While HR values of 5/7, 7/7, and 7/5 are appropriate for staggered canyons. In addition, in terms of improving indoor air quality by natural ventilation, the staggered canyons with favorable HR are better than those of the regular canyons.

  17. Effects of animal activity and air temperature on methane and ammonia emissions from a naturally ventilated building for dairy cows

    Science.gov (United States)

    Ngwabie, N. M.; Jeppsson, K.-H.; Gustafsson, G.; Nimmermark, S.

    2011-12-01

    Knowledge of how different factors affect gas emissions from animal buildings can be useful for emission prediction purposes and for the improvement of emission abatement techniques. In this study, the effects of dairy cow activity and indoor air temperature on gas emissions were examined. The concentrations of CH 4, NH 3, CO 2 and N 2O inside and outside a dairy cow building were measured continuously between February and May together with animal activity and air temperature. The building was naturally ventilated and had a solid concrete floor which sloped towards a central urine gutter. Manure was scraped from the floor once every hour in the daytime and once every second hour at night into a partly covered indoor pit which was emptied daily at 6 a.m. and at 5 p.m. Gas emissions were calculated from the measured gas concentrations and ventilation rates estimated by the CO 2 balance method. The animal activity and emission rates of CH 4 and NH 3 showed significant diurnal variations with two peaks which were probably related to the feeding routine. On an average day, CH 4 emissions ranged from 7 to 15 g LU -1 h -1 and NH 3 emissions ranged from 0.4 to 1.5 g LU -1 h -1 (1 LU = 500 kg animal weight). Mean emissions of CH 4 and NH 3 were 10.8 g LU -1 h -1 and 0.81 g LU -1 h -1, respectively. The NH 3 emissions were comparable to emissions from tied stall buildings and represented a 4% loss in manure nitrogen. At moderate levels, temperature seems to affect the behaviour of dairy cows and in this study where the daily indoor air temperature ranged from about 5 up to about 20 °C, the daily activity of the cows decreased with increasing indoor air temperature ( r = -0.78). Results suggest that enteric fermentation is the main source of CH 4 emissions from systems of the type in this study, while NH 3 is mainly emitted from the manure. Daily CH 4 emissions increased significantly with the activity of the cows ( r = 0.61) while daily NH 3 emissions increased

  18. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

    Science.gov (United States)

    Battista, L.; Sciuto, S. A.; Scorza, A.

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10-4 m3/s (18.0 l/min) for the mono-directional sensor and a measurement range of ±3.00 × 10-4 m3/s (±18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the

  19. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

    Science.gov (United States)

    Battista, L; Sciuto, S A; Scorza, A

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)∕s (18.0 l∕min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)∕s (±18.0 l∕min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono

  20. 谈建筑暖通空调的设计要点%On design for architectural heat-ventilation air-conditioners

    Institute of Scientific and Technical Information of China (English)

    王康成

    2015-01-01

    The paper indicates the concept for the heat-ventilation air-conditioner system,describes its basic key points of design from the design planning,loading calculation of air-conditioners,and ventilation system design,and puts forward the matters needing attention in the design,so as to ensure the design quality of the heat-ventilation air-conditioner system.%简述了暖通空调系统的含义,从设计规划、空调负荷计算、通风系统设计等方面,论述了建筑暖通空调的基本设计要点,提出了在设计中应该注意的问题,以保证暖通空调系统的设计质量。

  1. Improved inhaled air quality at reduced ventilation rate by control of airflow interaction at the breathing zone with lobed jets

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Spilak, Michal

    2014-01-01

    Inhaled air quality at a reduced supply of clean air was studied by controlling the airflow interaction at the breathing zone of a person using lobed jets as part of personalized ventilation (PV). Experiments were performed in a full-scale test room at 23°C (73.4°F) with a breathing thermal manikin......) equivalent diameter. The nozzles were positioned frontally at the face within the boundary layer and centered to the mouth. The enhancement of inhaled air quality by changing the initial velocity (0.2-0.6 m/s, 0.66-1.97 fps) and the distance from the mouth (0.02-0.06 m, 0.07-0.20 ft) was studied. The control...... over the interaction between the inserted jets and the free convection flow was efficient. Over 80% clean PV air was measured in inhalation. The worst performing nozzle was the four-leafed clover: its best performance yielded 23% clean air inhalation, at the shortest distance and the highest velocity...

  2. The impact of human perception of simultaneous exposure to thermal load, low-frequency ventilation noise and indoor air pollution

    DEFF Research Database (Denmark)

    Alm, Ole; Witterseh, Thomas; Clausen, Geo

    1999-01-01

    Human perception of simultaneous exposure to combinations of three different levels of operative temperature, low-frequency ventilation noise and indoor air pollution (27 combinations) was studied in climate chambers. The operative temperatures studied were: 26.0 deg.C, 27.6 deg.C and 29.6 deg.......C, and the sound pressure levels were: 45 dB(A), 48 dB(A) and 51 dB(A). The air pollution corresponding to these three levels of perceived air quality (at 26 deg.C) was: 1.1 decipol (dp), 2.4 dp and 4.5 dp. A 1 deg.C change in operative temperature had the same impact on the human perception of the overall...... conditions as a change of 3.8 dB(A) in sound pressure level or a change of 7 dp in air pollution (at 26 deg.C). The percentage of dissatisfied with the perceived air quality increased with increasing temperature. An elevated temperature had a dominant impact on the human perception of the indoor environment...

  3. The impact of human perception of simultaneous exposure to thermal load, low-frequency ventilation noise and indoor air pollution

    DEFF Research Database (Denmark)

    Alm, Ole; Witterseh, Thomas; Clausen, Geo

    1999-01-01

    Human perception of simultaneous exposure to combinations of three different levels of operative temperature, low-frequency ventilation noise and indoor air pollution (27 combinations) was studied in climate chambers. The operative temperatures studied were: 26.0 deg.C, 27.6 deg.C and 29.6 deg.......C, and the sound pressure levels were: 45 dB(A), 48 dB(A) and 51 dB(A). The air pollution corresponding to these three levels of perceived air quality (at 26 deg.C) was: 1.1 decipol (dp), 2.4 dp and 4.5 dp. A 1 deg.C change in operative temperature had the same impact on the human perception of the overall...... conditions as a change of 3.8 dB(A) in sound pressure level or a change of 7 dp in air pollution (at 26 deg.C). The percentage of dissatisfied with the perceived air quality increased with increasing temperature. An elevated temperature had a dominant impact on the human perception of the indoor environment...

  4. The Development of Equilibrium After Preheating

    CERN Document Server

    Kofman, L A

    2001-01-01

    We present a fully nonlinear study of the development of equilibrium after preheating. Preheating is the exponentially rapid transfer of energy from the nearly homogeneous inflaton field to fluctuations of other fields and/or the inflaton itself. This rapid transfer leaves these fields in a highly nonthermal state with energy concentrated in infrared modes. We have performed lattice simulations of the evolution of interacting scalar fields during and after preheating for a variety of inflationary models. We have formulated a set of generic rules that govern the thermalization process in all of these models. Notably, we see that once one of the fields is amplified through parametric resonance or other mechanisms it rapidly excites other coupled fields to exponentially large occupation numbers. These fields quickly acquire nearly thermal spectra in the infrared, which gradually propagates into higher momenta. Prior to the formation of total equilibrium, the excited fields group into subsets with almost identica...

  5. Investigation of the Indoor Environment in a Passive House Apartment Building Heated by Ventilation Air

    DEFF Research Database (Denmark)

    Lysholt Hansen, MathiasYoung Bok; Koulani, Chrysanthi Sofia; Peuhkuri, Ruut Hannele;

    2014-01-01

    Experience has shown that appropriate design of very low energy dwellings can be a large challenge and that the final design may result in insufficient heating in winter and overheating in summer. The 126 certified Passive House apartments (Ravnsborghusene) in Køge, Denmark are a low energy build...... with south oriented windows, static shadings by the balcony overhangs and low ventilation rates, resulted in excessive hours of overheating....

  6. Testing of blowers and HVAC systems. Guide for energy optimization regarding ambient air ventilation systems. Pruefungen von Ventilatoren und Raumlufttechnischen Geraeten. Wegweiser zur Energieoptimierung bei RLT-Geraeten

    Energy Technology Data Exchange (ETDEWEB)

    Breit, O.

    1992-09-01

    Through a continuously increasing environmental consciousness and the increase of energy cost to be expected in the next years, ambient air ventilation systems with an optimized energy consumption are increasingly applied. For the determination of the energy consumption, special test rigs for the capacity are necessary. They consist of two climatic chambers arranged side by side, two measured sections and two speed controlled supporting fans. The tests carried out on the capacity and function of ambient air ventilation systems showed that the power consumption and thus, the energy consumption can be considerably reduced through constructional changes and an exact design of single components based on measured results. (BWI).

  7. ASME N511-19XX, Standard for periodic in-service testing of nuclear air treatment, heating, ventilating and air conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    A draft version of the Standard is presented in this document. The Standard covers the requirements for periodic in-service testing of nuclear safety-related air treatment, heating, ventilating, and air conditioning systems in nuclear facilities. The Standard provides a basis for the development of test programs and does not include acceptance criteria, except in cases where the results of one test influence the performance of other tests. The Standard covers general inspection and test requirements, reference values, inspection and test requirements, generic tests, acceptance criteria, in-service test requirements, testing following an abnormal incident, corrective action requirements, and quality assurance. Mandatory appendices provide a visual inspection checklist and four test procedures. Non-mandatory appendices provide additional information and guidance on mounting frame pressure leak test procedure, corrective action, challenge gas substitute selection criteria, and test program development. 8 refs., 10 tabs.

  8. Physical features of small disperse coal dust fraction transportation and structurization processes in iodine air filters of absorption type in ventilation systems at nuclear power plants

    CERN Document Server

    Ledenyov, Oleg P; Poltinin, P Ya; Fedorova, L I

    2012-01-01

    The research on the physical features of transportation and structurization processes by the air-dust aerosol in the granular filtering medium with the cylindrical coal adsorbent granules in an air filter of the adsorption type in the heating ventilation and cooling (HVAC) system at the nuclear power plant is completed. The physical origins of the coal dust masses distribution along the absorber with the granular filtering medium with the cylindrical coal granules during the air-dust aerosol intake process in the near the surface layer of absorber are researched. The quantitative technical characteristics of air filtering elements, which have to be considered during the optimization of air filters designs for the application in the ventilation systems at the nuclear power plants, are obtained.

  9. Design of Air Conditioning and Ventilating System of the Shanxi Theatre%山西大剧院空调通风设计浅析

    Institute of Scientific and Technical Information of China (English)

    刘艳云

    2012-01-01

    This paper describes the design of air conditioning and ventilating system of the shanxi theatre. Auditoria of the theatre applies air supply under seat and air exhaust from roof. Air-conditioning system of auditorium is divided by height, and the water system adopts partition-dual. Air conditioning and ventilating system uses more comprehensive noise and vibration reduction measures.%本文介绍了山西大剧院空调通风系统设计。剧场观众厅采用座椅下送风,屋顶高位排风,观众厅按高度划分空调系统,空调水系统采用分区双管制,空调通风系统做了较全面的消声减振措施。

  10. Thermal comfort and indoor air quality in the lecture room with 4-way cassette air-conditioner and mixing ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Kwang-Chul; Jang, Jae-Soo; Oh, Myung-Do [Department of Mechanical and Information Engineering, University of Seoul, Seoul 130-743 (Korea, Republic of)

    2007-02-15

    We performed the experimental and the numerical studies on thermal comfort (TC) and indoor air quality (IAQ) in the lecture room with cooling loads when the operating conditions are changed. Predicted mean vote (PMV) value and CO{sub 2} concentration of the lecture room were measured and compared to the numerical results. Both of them showed a reasonable agreement with each other and then we applied the numerical model to analyze TC and IAQ for a couple of different operating conditions. From the results we found that the increment of the discharge angle of 4-way cassette air-conditioner makes uniformity of TC worse, but rarely affects IAQ. It turned out that TC and IAQ are hardly affected by the variation of the discharge airflow. Finally TC was merely affected by the increment of the ventilation rate, but when the ventilation rate is more than 800m{sup 3}/h, the average CO{sub 2} concentration can be satisfied with the standard limits of Japanese in our case studies. (author)

  11. Laboratory testing of a displacement ventilation diffuser for underfloor air distribution systems

    OpenAIRE

    Raftery, Paul; Bauman, Fred; Schiavon, Stefano; Epp, Tom

    2015-01-01

    Underfloor air distribution (UFAD) systems use the underfloorplenum beneath a raised floor to provide conditioned air through floor-mounted diffusers, which typically discharge cool air with bothhorizontal and vertical momentum components. These systems usually createa vertical temperature stratification when in cooling mode and this hasan impact on energy, indoor air quality and thermal comfort. The purposeof this study was to characterize the stratification performance of apreviously unstud...

  12. Prototype of a computer method for designing and analyzing heating, ventilating and air conditioning proportional, electronic control systems

    Science.gov (United States)

    Barlow, Steven J.

    1986-09-01

    The Air Force needs a better method of designing new and retrofit heating, ventilating and air conditioning (HVAC) control systems. Air Force engineers currently use manual design/predict/verify procedures taught at the Air Force Institute of Technology, School of Civil Engineering, HVAC Control Systems course. These existing manual procedures are iterative and time-consuming. The objectives of this research were to: (1) Locate and, if necessary, modify an existing computer-based method for designing and analyzing HVAC control systems that is compatible with the HVAC Control Systems manual procedures, or (2) Develop a new computer-based method of designing and analyzing HVAC control systems that is compatible with the existing manual procedures. Five existing computer packages were investigated in accordance with the first objective: MODSIM (for modular simulation), HVACSIM (for HVAC simulation), TRNSYS (for transient system simulation), BLAST (for building load and system thermodynamics) and Elite Building Energy Analysis Program. None were found to be compatible or adaptable to the existing manual procedures, and consequently, a prototype of a new computer method was developed in accordance with the second research objective.

  13. Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4)).

    Science.gov (United States)

    Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

    2010-09-21

    In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air.Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b.

  14. Control and prevention of ice formation and accretion on heat exchangers for ventilation systems

    DEFF Research Database (Denmark)

    Rahimi, Maral; Afshari, Alireza

    2015-01-01

    In cold climates, the application of mechanical ventilation systems with heat recovery like are airto-air exchangers is used for reducing energy consumption for heating buildings by transferring heat exhausted air to supply air. However, increase efficiency of heat exchanger results in lower...... exhaust air temperatures and Ice formation on heat exchanger fins, which can cause problem and is not favourable. Therefore, prevention and control of ice formation on heat exchangers is necessary. The existing methods are divided into two different methods: active and passive ice control methods....... The active methods are e.g. bypass, recirculation, preheating. The passive methods relate to the surface characteristics of the heat exchanger fins as they have effect on ice formation in initial phase. All these methods have varying levels of success, cost, and effectiveness, which are depending on the heat...

  15. Low cost bare-plate solar air collector

    Energy Technology Data Exchange (ETDEWEB)

    Maag, W.L.; Wenzler, C.J.; Rom, F.E.; VanArsdale, D.R.

    1980-09-01

    The purpose of this project was to develop a low cost, bare-plate collector, determine its performance for a variety of climatic conditions, analyze the economics of this type of solar collector and evaluate specific applications. Two prototype collectors were designed, fabricated and installed into an instrumented test system. Tests were conducted for a period of five months. Results of the tests showed consistent operating efficiencies of 60% or greater with air preheat temperature uses up to 20/sup 0/F for one of the prototypes. The economic analyses indicated that an installed cost of between $5 and $10 per square foot would make this type of solar system economically viable. For the materials of construction and the type of fabrication and installation perceived, these costs for the bare-plate solar collector are believed to be attainable. Specific applications for preheating ventilation air for schools were evaluated and judged to be economically viable.

  16. Temperature equilization in the Luetzkendorf preheater

    Energy Technology Data Exchange (ETDEWEB)

    1943-01-30

    Suggestions are offered for improvement to attain more nearly uniform temperature distribution in the preheater inlet and outlet as well as for improvement of a loss of pressure in heating gas for raising the efficiency of the heating gas blower. The evaluation of the operating conditions from the standpoint of the heating gas were made in the hydrogenation works of Poelitz, in 1939 with the preheater constructed on the Ludwigshafen plan, and in Luetzkendorf on the preheater of the Leuna model. Both preheaters had two Schiele heating gas blowers of the type 1160. Operating conditions involving hairpin tubes, temperatures, resistance, volume, piping, pressure, and heat conduction were given for both plants. A sketch for the heating gas movement was mentioned in the report but was not included. Recommendations on the use of a new blower were given. Some of these were reducing the yield to 90,000 cubic meters per hour and using the same motors. The distribution of the amounts and of the temperature drop of the gas and of the material of the hairpins were given.

  17. Brain Cooling With Ventilation of Cold Air Over Respiratory Tract in Newborn Piglets: An Experimental and Numerical Study.

    Science.gov (United States)

    Bakhsheshi, Mohammad Fazel; Moradi, Hadi Vafadar; Stewart, Errol E; Keenliside, Lynn; Lee, Ting-Yim

    2015-01-01

    We investigate thermal effects of pulmonary cooling which was induced by cold air through an endotracheal tube via a ventilator on newborn piglets. A mathematical model was initially employed to compare the thermal impact of two different gas mixtures, O2-medical air (1:2) and O2-Xe (1:2), across the respiratory tract and within the brain. Following mathematical simulations, we examined the theoretical predictions with O2-medical air condition on nine anesthetized piglets which were randomized to two treatment groups: 1) control group ([Formula: see text]) and 2) pulmonary cooling group ([Formula: see text]). Numerical and experimental results using O2-medical air mixture show that brain temperature fell from 38.5 °C and 38.3 °C ± 0.3 °C to 35.7 °C ± 0.9 °C and 36.5 °C ± 0.6 °C during 3 h cooling which corresponded to a mean cooling rate of 0.9 °C/h ± 0.2 °C/h and 0.6 °C/h ± 0.1 °C/h, respectively. According to the numerical results, decreasing the metabolic rate and increasing air velocity are helpful to maximize the cooling effect. We demonstrated that pulmonary cooling by cooling of inhalation gases immediately before they enter the trachea can slowly reduce brain and core body temperature of newborn piglets. Numerical simulations show no significant differences between two different inhaled conditions, i.e., O2-medical air (1:2) and O2-Xe (1:2) with respect to cooling rate.

  18. Sensation of draft at ankles for displacement ventilation and underfloor air distribution systems

    OpenAIRE

    Schiavon, Stefano; Rim, Donghyun; Pasut, Wilmer; Nazaroff, William W.

    2014-01-01

    Draft is defined as an unwanted local convective cooling of the body caused by air movement (Fanger, 1977). The main factors that affect draft are air temperature and velocity (Houghten et al., 1938), air turbulence (Fanger et al., 1988), body parts exposed and clothing insulation level, and overall thermal comfort (Toftum et al., 2003). Historically, the literature on draft has focused on thermal discomfort at the neck, which was considered the most sensitive part of the body, especially as ...

  19. Human response to ductless personalized ventilation coupled with displacement ventilation

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Veselý, Michal; Melikov, Arsen K.

    2012-01-01

    A human subject experiment was carried out to investigate the extent to which ductless personalized ventilation (DPV) in conjunction with displacement ventilation can improve perceived air quality (PAQ) and thermal comfort at elevated room air temperature in comparison with displacement ventilation...... alone. The experimental conditions comprised displacement ventilation alone (room air temperature of 23 °C, 26 °C, 29 °C) and DPV with displacement ventilation (26 °C, 29 °C), both operating at supply air temperatures 3, 5 or 6K lower than room air temperature, as well as mixing ventilation (23 °C, 3 K......). During one hour exposure participants answered questionnaires regarding PAQ and thermal comfort. PAQ was significantly better with DPV than without DPV at the same background conditions. Thermal comfort improved when DPV was used. Combining DPV with displacement ventilation showed the potential...

  20. A survey and critical review of the literature on indoor air quality, ventilation and health symptoms in schools

    Energy Technology Data Exchange (ETDEWEB)

    Daisey, J.M. [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.; Angell, W.J. [Univ. of Minnesota, St. Paul, MN (United States)

    1998-03-01

    A survey and critical review were undertaken of existing published literature and reports on indoor air quality (IAQ), ventilation, and IAQ- and building-related health problems in schools, including California schools. Over 450 relevant publications were obtained and reviewed, including papers published in the archival peer-reviewed scientific literature, proceedings of scientific meetings, government reports, 77 NIOSH Health Hazard Evaluation Reports (HHER) and 70 reports on investigations of problem schools in California. Most of the reviewed literature was for complaint or problem schools. The types of health symptoms reported in schools were very similar to those defined as sick building syndrome (SBS) symptoms, although this may be due, at least in part, to the type of health symptom questionnaires used. Some of the symptoms, e.g., wheezing, are indicative of asthma. In the studies in which complaint and noncomplaint buildings or areas were compared, complaint buildings generally had higher rates of health symptoms.

  1. Application of local exhaust ventilation system and integrated collectors for control of air pollutants in mining company.

    Science.gov (United States)

    Ghorbani Shahna, Farshid; Bahrami, Abdulrahman; Farasati, Farhad

    2012-01-01

    Local exhaust ventilation (LEV) systems and integrated collectors were designed and implemented in a mining company in order to control emitted air pollutant from furnaces. The LEV was designed for capture and transition of air pollutants emitted from furnaces to the integrated collectors. The integrated collectors including four high efficiency Stairmand model cyclones for control of particulate matter, a venturi scrubber for control of the fine particles, SO(2) and a part of H(2)S to follow them, and a packed scrubber for treatment of the residual H(2)S and SO(2) were designed. Pollutants concentration were measured to determine system effectiveness. The results showed that the effectiveness of LEV for reducing workplace pollution is 91.83%, 96.32% and 83.67% for dust, SO(2) and H(2)S, respectively. Average removal efficiency of particles by combination of cyclone and venturi scrubber was 98.72%. Average removal efficiency of SO(2) and H(2)S were 95.85% and 47.13% for the venturi scrubber and 68.45% and 92.7% for the packed bed scrubber. The average removal efficiency of SO(2) and H(2)S were increased to 99.1% and 95.95% by the combination of venturi and packed bed scrubbers. According to the results, integrated collectors are a good air pollution control option for industries with economic constraints and ancient technologies.

  2. Semi-volatile organic compounds in heating, ventilation, and air-conditioning filter dust in retail stores.

    Science.gov (United States)

    Xu, Y; Liang, Y; Urquidi, J R; Siegel, J A

    2015-02-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories of semi-volatile organic compounds (SVOCs). Filters in heating, ventilation, and air-conditioning (HVAC) system collect particles from large volumes of air and thus potentially provide spatially and temporally integrated SVOC concentrations. This study measured six phthalate and 14 PBDE compounds in HVAC filter dust in 14 retail stores in Texas and Pennsylvania, United States. Phthalates and PBDEs were widely found in the HVAC filter dust in retail environment, indicating that they are ubiquitous indoor pollutants. The potential co-occurrence of phthalates and PBDEs was not strong, suggesting that their indoor sources are diverse. The levels of phthalates and PBDEs measured in HVAC filter dust are comparable to concentrations found in previous investigations of settled dust in residential buildings. Significant correlations between indoor air and filter dust concentrations were found for diethyl phthalate, di-n-butyl phthalate, and benzyl butyl phthalate. Reasonable agreement between measurements and an equilibrium model to describe SVOC partitioning between dust and gas-phase is achieved. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system - a human response study in hot and humid climate

    DEFF Research Database (Denmark)

    Bin, Yang; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration...

  4. Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings – Guideline of the German Society for Hospital Hygiene (DGKH

    Directory of Open Access Journals (Sweden)

    Külpmann, Rüdiger

    2016-02-01

    Full Text Available Since the publication of the first “Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems in hospitals” ( in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section “Ventilation and air conditioning technology” attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

  5. Analysis and Choice of Optimal Heating Ventilation Air Conditioning System for a Teaching Unit

    Directory of Open Access Journals (Sweden)

    Marina Verdeş

    2007-01-01

    Full Text Available Under the conditions of present society in which providing an optimum interior comfort is confronted with the necessity of the energy consumption reduction, solving this problem depends on the factors which contribute to the achievements of this comfort. Modern buildings -- implicitly teaching unit -- may be equipped with installations which have low energy consumption, respective a heating, cooling and ventilating integrated system with heat pumps system which can assure all the required comfort conditions. This paper underlines the necessity to use the heat pump in heating system for a teaching unit, energetic and economic guides and the possibility to increase them when using cooling and heating mixed. The solution of heat pumps for heating of the teaching unit and the energetic and economic advantages of the system is made in study.

  6. The correlation of Acanthamoeba from the ventilation system with other environmental parameters in commercial buildings as possible indicator for indoor air quality

    Science.gov (United States)

    OOI, Soo Shen; MAK, Joon Wah; CHEN, Donald K.F.; AMBU, Stephen

    2016-01-01

    The free-living protozoan Acanthamoeba is an opportunistic pathogen that is ubiquitous in our environment. However, its role in affecting indoor air quality and ill-health of indoor occupants is relatively unknown. The present study investigated the presence of Acanthamoeba from the ventilation system and its correlation with other indoor air quality parameters, used in the industry code of practice and its potential as an indicator for indoor air quality. Indoor air quality assessments were carried out in nine commercial buildings with approval from the building management, and the parameters assessed were as recommended by the Department of Occupational Safety and Health. The presence of Acanthamoeba was determined through dust swabs from the ventilation system and indoor furniture. Logistic regression was performed to study the correlation between assessed parameters and occupants’ complaints. A total of 107 sampling points were assessed and 40.2% of the supplying air diffuser and blowing fan and 15% of the furniture were positive for cysts. There was a significant correlation between Acanthamoeba detected from the ventilation system with ambient total fungus count (r=0.327; p=0.01) and respirable particulates (r=0.276; p=0.01). Occupants’ sick building syndrome experience also correlated with the presence of Acanthamoeba in the ventilation system (r=0.361; p=0.01) and those detected on the furniture (r=0.290; p=0.01). Logistic regression showed that there was a five-fold probability of sick building syndrome among occupants when Acanthamoeba was detected in the ventilation system. PMID:27476379

  7. Research on a Household Dual Heat Source Heat Pump Water Heater with Preheater Based on ASPEN PLUS

    Directory of Open Access Journals (Sweden)

    Xiang Gou

    2016-12-01

    Full Text Available This article proposes a dual heat source heat pump bathroom unit with preheater which is feasible for a single family. The system effectively integrates the air source heat pump (ASHP and wastewater source heat pump (WSHP technologies, and incorporates a preheater to recover shower wastewater heat and thus improve the total coefficient of performance (COP of the system, and it has no electric auxiliary heating device, which is favorable to improve the security of the system operation. The process simulation software ASPEN PLUS, widely used in the design and optimization of thermodynamic systems, was used to simulate various cases of system use and to analyze the impact of the preheater on the system. The average COP value of a system with preheater is 6.588 and without preheater it is 4.677. Based on the optimization and analysis, under the standard conditions of air at 25 °C, relative humidity of 70%, wastewater at 35 °C, wastewater flow rate of 0.07 kg/s, tap water at 15 °C, and condenser outlet water temperature at 50 °C, the theoretical COP of the system can reach 9.784 at an evaporating temperature of 14.96 °C, condensing temperature of 48.74 °C, and preheated water temperature of 27.19 °C.

  8. Hygienic Evaluation of Air Ventilation System in Air-Conditioned Carriages%空调列车通风系统卫生学评价

    Institute of Scientific and Technical Information of China (English)

    张贵生

    2012-01-01

    [ Objective ] To collect evidences of air ventilation system pollution of air-conditioned carriages and to provide scientific basis and reasonable proposals for disease prevention, [Methods ] Three models of representative air-conditioned carriages (25G, 25T and CRH-5) were selected, and each was monitored at 4 sampling points including hard seat, hard berth, soft berth and dining-car in April, May and June of 2011. The monitoring indices of air supply system included temperature, humidity, inhalable particles (PM10), air exchange flow and the total colony forming units (CFU) of bacteria, fungi and β-type hemolytic streptococcus. The monitoring indices of air ventilation ducts included the amount of dust particles and the total CFU of bacteria and fungi. The monitoring index of condensed water was Legionella pneumophila. [ Results ] No Legionella pneumophila was found in the condensed water of air ventilation system of 25G and 25T carriages. The average air exchange flow of 25G, 25T and CRH-5 carriages were (49.1 ± 10.3), (41.5 ± 18.1) and (52.4 ± 12.3) m3/(h · p) respectively. In the air supply system, the average humidity were (40.1 ± 1.5)%, (29.4 ± 13)% and (42.1 ± 4.5)% respectively; the average CFU of bacteria were (603.7 ± 124.0), (643.3 ± 331.3) and (256.5 ± 67.7)cfu/m3 respectively; the average CFU of fungi were (148.7 ± 39.7), (216.8 ± 227.6) and 0.0cfu/m3 respectively; the average CFU of β-type hemolytic streptococcus were (7.3 ± 5.6), 0.0 and 0.0cfu/m3 respectively. In the air ventilation duct, the average amount of dust particles were (8.5 ± 1.5), (9.2 ± 8.7) and (5.0 ± 0.5) g/m2 respectively. There was a significant difference in humidity among selected models (F=4.685 6, P=0.011 5), but no significant difference was found in other monitoring indices. [ Conclusion ] The problems of the amount of dust particles in air ventilation ducts and the total CFU of bacteria, fungi and β-type hemolytic streptococcus in air supply system of

  9. New air terminal devices with high efficiency for personalized ventilation application

    DEFF Research Database (Denmark)

    Bolashikov, Z.; Nikolaev, L.; Melikov, Arsen Krikor

    2003-01-01

    /20oC respectively, and at different flow rates of personalized air, ranging from 5 to 15 L/s for RMP and 0.18 to 0.5 L/s for Headset. A breathing thermal manikin was used to evaluate the inhaled air quality achieved with the developed ATDs as well as the performance in regard to thermal comfort....... The results revealed that inhaled air consisting of 100% personalized air was achieved with the RMP and up to 80% with the Headset. The change in room temperature that would have affected whole-body heat loss equivalently, ranged from less than 0.5 K to 2.2 K for RMP and almost 0 K for the Headset....

  10. Oxygen and carbon dioxide sensitivity of ventilation in amphibious crabs, Cardisoma guanhumi, breathing air and water.

    Science.gov (United States)

    Gannon, Andrew T; Henry, Raymond P

    2004-05-01

    Amphibious crabs, Cardisoma guanhumi, were acclimated to breathing either air or water and exposed to altered levels of oxygen and/or carbon dioxide in the medium. Hypercapnia (22, 36 and 73 torr CO(2)) stimulated a significant hypercapnic ventilatory response (HCVR) in both groups of crabs, with a much greater effect on scaphognathite frequency (Deltaf(SC)=+700%) in air-breathing crabs than water-breathing crabs (Deltaf(SC)=+100%). In contrast, hyperoxia induced significant hypoventilation in both sets of crabs. However, simultaneous hyperoxia and hypercapnia triggered a greater than 10-fold increase in f(SC) in air-breathing crabs but no change in water-breathing crabs. For water-breathing crabs hypoxia simultaneous with hypercapnia triggered the same response as hypoxia alone-bradycardia (-50%), and a significant increase in f(SC) at moderate exposures but not at the more extreme levels. The response of air-breathing crabs to hypoxia concurrent with hypercapnia was proportionally closer to the response to hypercapnia alone than to hypoxia. Thus, C. guanhumi were more sensitive to ambient CO(2) than O(2) when breathing air, characteristic of fully terrestrial species, and more sensitive to ambient O(2) when breathing water, characteristic of fully aquatic species. C. guanhumi possesses both an O(2)- and a CO(2)-based ventilatory drive whether breathing air or water, but the relative importance switches when the respiratory medium is altered.

  11. CFD and Ventilation Research

    DEFF Research Database (Denmark)

    Li, Y.; Nielsen, Peter V.

    2011-01-01

    There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000–10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part of scienti......There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000–10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part...... of scientific research and engineering development of complex air distribution and ventilation systems in buildings. This review discusses the major and specific challenges of CFD in terms of turbulence modelling, numerical approximation, and boundary conditions relevant to building ventilation. We emphasize...... analysis in ventilation research, rather it has become an increasingly important partner....

  12. Recent Advances in Electrical Resistance Preheating of Aluminum Reduction Cells

    Science.gov (United States)

    Ali, Mohamed Mahmoud; Kvande, Halvor

    2017-02-01

    There are two mainpreheating methods that are used nowadays for aluminum reduction cells. One is based on electrical resistance preheating with a thin bed of small coke and/or graphite particles between the anodes and the cathode carbon blocks. The other is flame preheating, where two or more gas or oil burners are used. Electrical resistance preheating is the oldest method, but is still frequently used by different aluminum producers. Many improvements have been made to this method by different companies over the last decade. In this paper, important points pertaining to the preparation and preheating of these cells, as well as measurements made during the preheating process and evaluation of the performance of the preheating, are illustrated. The preheating times of these cells were found to be between 36 h and 96 h for cell currents between 176 kA and 406 kA, while the resistance bed thickness was between 13 mm and 60 mm. The average cathode surface temperature at the end of the preheating was usually between 800°C and 950°C. The effect of the preheating methods on cell life is unclear and no quantifiable conclusions can be drawn. Some works carried out in the mathematical modeling area are also discussed. It is concluded that there is a need for more studies with real situations for preheated cells on the basis of actual measurements. The expected development in electrical resistance preheating of aluminum reduction cells is also summarized.

  13. Pre-heating mitigates composite degradation.

    Science.gov (United States)

    Silva, Jessika Calixto da; Rogério Vieira, Reges; Rege, Inara Carneiro Costa; Cruz, Carlos Alberto dos Santos; Vaz, Luís Geraldo; Estrela, Carlos; Castro, Fabrício Luscino Alves de

    2015-01-01

    Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey's tests (α=5%). Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (pheated specimens presented higher radiopacity values than non-pre-heated specimens (pheated specimens (pheating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  14. Selection of optimum blowers is higly important for energy conservation in ventilation and air conditioning engineering: High-performance radial blowers without a housing; Auswahl des optimalen Ventilators fuer Energieeinsparung in der Luft- und Klimatechnik von grosser Bedeutung: Hochleistungs-Radialventilatoren ohne Gehaeuse

    Energy Technology Data Exchange (ETDEWEB)

    Lexis, J. [Ingenieurbuero Beratung und Planung Luft- und Klimatechnik, Feucht bei Nuernberg (Germany)

    1998-12-01

    There isn`t another component in ventilation and air-conditioning whose choice can result in as much energy conservation as the choice of the optimum blower. Awareness of this fact is increasing. (orig.) [Deutsch] Mit keiner anderen Komponente in der Luft- und Klimatechnik kann so viel Energie gespart werden wie mit der Auswahl des optimalen Ventilators. Deshalb wird der Auswahl des Ventilators immer mehr Aufmerksamkeit geschenkt. (orig.)

  15. Heat flux to the helium cryogenic system elements in the case of incidental vacuum vessel ventilation with atmospheric air

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The selection process for size in safety equipment for cold vessels or process pipes in cryogenic systems should take into consideration the incidental ventilation of the vacuum vessel with atmospheric air. In this case, a significant heat input toward the cold elements of the system can be expected. A number of experimental investigations have been done for the elements at liquid helium temperature which have been covered with 10 layers of MLI. The typical values of the heat flux were measured in a range of 3.7 to 5.0 kW/m2 of the element surface. The helium temperature parts are typically surrounded by thermal shields that are kept in a temperature range of 50-80K. On the external side, the thermal shields are covered with 30-40 layers of MLI while on the internal side, the shields are bare. The theoretical calculations of heat flux to the thermal shield, with respect to the possibility of air condensation and freezing on the bare side of the thermal shield, show that the heat flux to the thermal shield can...

  16. Multifamily Ventilation Retrofit Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Lstiburek, J. [Building Science Corporation (BSC), Somerville, MA (United States); Bergey, D. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  17. Diffuse ceiling ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen

    both thermal comfort and energy efficient aspects. The present study aims to characterize the air distribution and thermal comfort in the rooms with diffuse ceiling ventilation. Both the stand-alone ventilation system and its integration with a radiant ceiling system are investigated. This study also...

  18. Spectroscopic Measurements of Target Preheating on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Elton, R.C.; Griem, H.R.; Iglesias, E.J.

    2000-02-28

    The preheating of laser-heated microballoon targets has been measured by time-resolved x-ray and extreme ultraviolet (euv) spectroscopy on the 30 kJ, 351 nm, 60-beam laser-fusion system at the University of Rochester Laboratory for Laser Energetics. Thin coatings of aluminum overcoated with magnesium served as indicators. both the sequence of the x-ray line emission and the intensity of euv radiation were used to determine a preheating peaking at {approx} 10 ns prior to onset of the main laser pulse, with a power density {approx_equal}1% of the main pulse. The measurements are supported by numerical modeling. Further information is provided by absorption spectra from the aluminum coating, backlighted by continuum from the heated surface. The exact source of the preheating energy remains unknown at present, but most likely arrives from early laser leakage through the system. The present target diagnostic is particularly useful when all beams cannot be monitored directly at all laser wavelengths.

  19. Violent Preheating in Inflation with Nonminimal Coupling

    CERN Document Server

    Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori

    2016-01-01

    We study particle production at the preheating era in inflation models with nonminimal coupling $\\xi \\phi^2R$ and quartic potential $\\lambda \\phi^4/4$ for several cases: real scalar inflaton, complex scalar inflaton and Abelian Higgs inflaton. We point out that the preheating proceeds much more violently than previously thought. If the inflaton is a complex scalar, the phase degree of freedom is violently produced at the first stage of preheating. If the inflaton is a Higgs field, the longitudinal gauge boson production is similarly violent. This is caused by a spike-like feature in the time dependence of the inflaton field, which may be understood as a consequence of short time scale during which the effective potential or kinetic term changes suddenly. The produced particles typically have very high momenta $k \\lesssim \\sqrt{\\lambda}M_\\text{P}$. The production might be so strong that almost all the energy of the inflaton is carried away within one oscillation for $\\xi^2\\lambda \\gtrsim 1$. This may significa...

  20. Metric-torsion preheating: cosmic dynamo mechanism?

    CERN Document Server

    de Andrade, L C Garcia

    2014-01-01

    Earlier Bassett et al [Phys Rev D 63 (2001) 023506] investigated the amplification of large scale magnetic fields during preheating and inflation in several different models. They argued that in the presence of conductivity resonance effect is weakened. From a dynamo equation in spacetimes endowed with torsion recently derived by Garcia de Andrade [Phys Lett B 711: 143 (2012)] it is shown that a in a universe with pure torsion in Minkowski spacetime the cosmological magnetic field is enhanced by ohmic or non-conductivity effect, which shows that the metric-torsion effects is worth while of being studied. In this paper we investigated the metric-torsion preheating perturbation, which leads to the seed cosmological magnetic field in the universe with torsion is of the order of $B_{seed}\\sim{10^{-37}Gauss}$ which is several orders of magnitude weaker than the decoupling value obtained from pure metric preheating of $10^{-15}Gauss$. Despite of the weakness of the magnetic field this seed field may seed the galact...

  1. Effect of preheating on potato texture.

    Science.gov (United States)

    Andersson, A; Gekas, V; Lind, I; Oliveira, F; Oste, R

    1994-01-01

    Preheating potatoes at 50 to 80 degrees C has a firming effect on the cooked potato tissue. This effect is particularly pronounced at a preheating temperature of 60 to 70 degrees C followed by cooling. Several theories have been presented in the literature to explain this firming effect: retrogradation of starch, leaching of amylose, stabilization of the middle lamellae and cell walls by the activation of the pectin methylesterase (PME) enzyme, and by the release of calcium from gelatinized starch and the formation of calcium bridges between pectin molecules. Most probably, none of these theories alone can explain the phenomenon and more than one mechanism seems to be involved. Some of these mechanisms seem to be interdependent. As an example, calcium could be considered as a link all the way through release after starch gelatinization to cross-linking pectin substances in the cell wall and the middle lamellae, which has been demethylated by the PME enzyme. More research and "clear cut" experiments are needed in order to elucidate the role of each mechanism, especially which of them is the main contributor to the process of firming. Most probably, the calcium-pectin-PME mechanism plays a secondary role, that is, it only retards the collapse of the tissue structure that would otherwise occur during the final heating without preheating, and it is not the main factor of firmness.

  2. AN IMPACT OF THE EFFICIENT FUNCTIONING OF THE VENTILATION AND AIR-CONDITIONING SYSTEM ON THERMAL COMFORT OF THE MEDICAL STAFF IN THE OPERATING ROOM

    Directory of Open Access Journals (Sweden)

    Tomasz Jankowski

    2016-11-01

    Full Text Available Ventilation and air conditioning systems are necessary for developing proper parameters of indoor envi-ronment in operating rooms. The main task of ventilation and air conditioning in those specific areas consists in creating desirable temperature, reducing the number of microorganisms and the concen-trations of hazardous gases and substances in the air, as well as ensuring the proper direction of airflow. In Poland, indoor environment in operating rooms has to comply with the requirements set out in three regulations (Journal of Laws of 2002 No. 75, item 690, as amended, Journal of Laws of 2002 No. 217, item 1833, Journal of Laws of 2011 No. 31, item 158, as amended and the document entitled "Guidelines for the design of general hospitals". Given insufficient accuracy of the abovementioned national documents, it is a common practice to use foreign standards, i.e. ASHRAE Standard 170-2013, DIN 1946-4: 2008 and FprCEN TR 16244: 2011. When considering the conditions for thermal comfort, it is important to bear in mind a close link between air flow velocity and air temperature. Air in the zone occupied by patients and medical staff must not cause the sensation of draft. Furthermore, air velocity should be sufficient to eliminate interference caused by the presence of people and other sources of heat. It should also reduce the turbulence level in the air in the operating room. Efficient functioning of ventilation and air conditioning was tested during treatments and operations carried out on three wards of a Warsaw hospital. Tests were performed with the participation of medical staff from various surgical units. They were asked to perform minor manual tasks to simulate work on the op-erating table, and to complete a questionnaire on subjective thermal sensation. The applied methodology is widely used during testing of general and local ventilation in public buildings. Air temperature, relative humidity, air flow supply and exhaust air from the

  3. Inhaled air quality with desk incorporated personalized ventilation (PV): parametric study

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Nagano, Hideaki; Melikov, Arsen Krikor

    manikin was seated with abdomen pressed against the table edge. The amount of clean air inhaled by the manikin was measured under numerous experiments studying different combinations of personalized airflow rates (isothermal) - 2, 4, 6, 8 and 10 L/s, widths of the two jets - 0.03 and 0.06 m, posture...... of the manikin - seated with the abdomen pressed against the table edge, moved backwards from or leaned over the table. The best performance was achieved with the 0.06 m openings: 85% of PV air was inhaled by the occupant at 10 L/s. The portion of clean PV air inhaled by the manikin was 80% when it was bent over...

  4. Study of Air Pollution Due to Plasma Cutting Process and Designing Local Ventilation System with Collector in Central Workshop of Mobarakeh Steel Company

    Directory of Open Access Journals (Sweden)

    Farideh Atabi

    2014-06-01

    Full Text Available Background & Objectives : Cutting leads to production of different hazardous agents such as fumes, particles, gases and vapors. In various studies, the effects of fumes, gases, and vapors on workers and environment have been proved. Meanwhile, cutting alloying plates with plasma cutting machine due to containing various alloy materials produces a lot of air pollution. Therefore, using the ventilation system to remove the mentioned pollution has always been noteworthy. Method: This study was performed on plasma cutting machine at Mobarakeh Steel Company. At first, according to ASTM the elements from alloy plates with optical emission spectrometry crm-35000-quantometery were detected, the air pollution from cutting the mentioned plates was sampled and measured using NIOSH 7300 method and according to the ACGIH:VS-72-20, VS-70-12, VS-70-11 VS-916 push-pull ventilation with bag filter collector was designed. Results: Results of sampling from pollution of cutting the alloy material, concentration of iron, lead and cadmium fumes were more than the standard limits. After calculation for push system, air flow volume of 195.163 cfm, outgoing air velocity of 5937.4 fpm and for pull system air flow volume of 12498 cfm, minimum duct velocity of 3000 fpm and velocity pressure of duct of 0.717 inwg, for fan, total pressure of 6.301 inwg, static pressure of 0.587 inwg and power of 20.65 Bhp and for collector with pulse jet cleaning system air to cloth ratio of 7 and dimensions of 6.88ft × 6.56ft × 9.84ft were obtained. Conclusion: The result of study indicated that push pull ventilation compared to other ventilation system s for plasma cutting has more efficiency and makes suitable control for pollution.

  5. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Science.gov (United States)

    Ecton, P. A.; Beatty, J.; Verbeck, G.; Lakshantha, W.; Rout, B.; Perez, J. M.

    2016-11-01

    We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  6. Free Convection Personalized Ventilation (FCPV)

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Normally we supply fresh air to a room with a diffuser, and this air is distributed in the room according to different principles as: mixing ventilation, displacement ventilation etc. That means we have to supply a very large amount of air to the whole room, although a person in the room totally...

  7. Stratified Flow in a Room with Displacement Ventilation and Wall-Mounted Air Terminal devices

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    This paper describes experiments with wall-mounted air terminal devices. The stratified flow in the room is analyzed, and the influence of stratification and the influence of room dimensions on the velocity level and on the length scale are proved. The velocity level in the occupied zone can be d...

  8. Investigation of the Indoor Environment in a Passive House Apartment Building Heated by Ventilation Air

    DEFF Research Database (Denmark)

    Lysholt Hansen, MathiasYoung Bok; Koulani, Chrysanthi Sofia; Peuhkuri, Ruut Hannele

    2014-01-01

    building project finished medio 2012. The design challenge was met with a concept of air heating that is individually controlled in every room. It also applies external solar shading. This study used indoor climate measurements and dynamic simulations in one of these apartment buildings to evaluate thermal...

  9. Heating, ventilating, and air conditioning deactivation thermal analysis of PUREX Plant

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.W.; Gregonis, R.A. [Westinghouse Hanford Company, Richland, WA (United States)

    1997-08-01

    Thermal analysis was performed for the proposed Plutonium Uranium Extraction Plant exhaust system after deactivation. The purpose of the analysis was to determine if enough condensation will occur to plug or damage the filtration components. A heat transfer and fluid flow analysis was performed to evaluate the thermal characteristics of the underground duct system, the deep-bed glass fiber filter No. 2, and the high-efficiency particulate air filters in the fourth filter building. The analysis is based on extreme variations of air temperature, relative humidity, and dew point temperature using 15 years of Hanford Site weather data as a basis. The results will be used to evaluate the need for the electric heaters proposed for the canyon exhaust to prevent condensation. Results of the analysis indicate that a condition may exist in the underground ductwork where the duct temperature can lead or lag changes in the ambient air temperature. This condition may contribute to condensation on the inside surfaces of the underground exhaust duct. A worst case conservative analysis was performed assuming that all of the water is removed from the moist air over the inside surface of the concrete duct area in the fully developed turbulent boundary layer while the moist air in the free stream will not condense. The total moisture accumulated in 24 hours is negligible. Water puddling would not be expected. The results of the analyses agree with plant operating experiences. The filters were designed to resist high humidity and direct wetting, filter plugging caused by slight condensation in the upstream duct is not a concern. 19 refs., 2 figs.

  10. Control of the Free Convective Flow around the Human Body for Enhanced Inhaled Air Quality: Application to a Seat-Incorporated Personalized Ventilation Unit

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Krenek, M.

    2010-01-01

    This paper reports on methods for control of the free convective flow around the human body, with the aim of improving inhaled air quality. The methods were studied with sea-incorporated personalized ventilation (PV)-two PV nozzles placed sideways at the head level of a seated occupant supplied...... the clean air. Another pair of control nozzles below the P V nozzles, the height of the shoulders, either provided an additional amount of clean PV air or exhausted part of the air from the free convective flow. The effectiveness of the methods for enhancing the quality of the inhaled air was studied...... of the supplied PV flows and of the control flows, etc., were performed under isothermal conditions at 20 degrees C (68 degrees F) and 26 degrees C (78.8 degrees F). The methods of control proved to be efficient and made it possible to increase the amount of clean air into inhalation at reduced personalized flow...

  11. Comparison of air-Q and Ambu Aura-i for controlled ventilation in infants: a randomized controlled trial.

    Science.gov (United States)

    Darlong, Vanlal; Biyani, Ghansham; Baidya, Dalim K; Pandey, Ravindra; Chandralekha; Punj, Jyotsna; Upadhyay, Ashish D

    2015-08-01

    The air-Q is a new supraglottic airway device (SAD) and has been increasingly used as a primary airway device and as a conduit for tracheal intubation in children as well as in adults. This device has either performed equally or better than other SADs in children. The Ambu Aura-i is a commonly used SAD in children undergoing various short surgical procedures. However, limited literature is available evaluating the safety and efficacy of the air-Q and the Ambu Aura-i in small children. We, therefore, conducted this study to compare the clinical performance of these two airway devices in infants weighing up to 10 kg. Our hypothesis is that air-Q, due to its improved and larger cuff design will yield better airway seal pressures as compared with the Ambu Aura-i. Sixty-four ASA I-II infants weighing Aura-i. After induction of general anesthesia (GA) and muscle relaxation, we measured oropharyngeal leak pressure (OLP) as the primary outcome. The secondary end points measured were time to insert, first insertion success rate, fiberoptic grade (FO) of laryngeal view and any other airway complications like trauma, laryngospasm, and desaturation. The air-Q ILA provided significantly higher OLP as compared with the Ambu Aura-i [20.2 ± 4.6 cm H2 O, CI 18.55-21.88; vs 16.2 ± 5.6 cmH2 O, CI 14.27-18.25, P = 0.003; mean difference 4 ± 1.29 cm H2 O, CI 1.41-6.58]. However, the Ambu Aura-i required significantly less time for its insertion (14.6 ± 2.8 s, CI 13.66-15.70; vs 16.3 ± 1.5 s, CI 15.75-16.86, P = 0.005; mean difference 1.625 ±  0.56 s, CI 0.48-2.76). There were no differences in first insertion success rate, FO view, and postoperative complications. We conclude that air-Q may be considered superior to Ambu Aura-i in infants for controlled ventilation as it provides higher airway sealing pressures. © 2015 John Wiley & Sons Ltd.

  12. Demand Controlled Economizer Cycles: A Direct Digital Control Scheme for Heating, Ventilating, and Air Conditioning Systems,

    Science.gov (United States)

    1984-05-01

    includes a heating coil and thermostatic control to maintain the air in this path at an elevated temperature, typically around 80 degrees Farenheit (80 F...1238 Aug 1 1236 1237 52 1074 1126 50 1033 1083 Sep 8 8 5W 862 7T 600 678 75 603 7r Oct 51 400 451 119 204 323 115 207 322 ov 64 123 287 187 71 258

  13. Study on Model of Indoor Air Pollution Forecast for Decoration Under Natural Ventilation Condition

    Institute of Scientific and Technical Information of China (English)

    YAN-FENG HONG; XUN CHEN; NING XU

    2005-01-01

    Objective To establish the model of indoor air pollution forecast for decoration. Methods The model was based on the balance model for diffusing mass. Results The data between testing concentration and estimating concentration were compared. The maximal error was less than 30% and average error was 14.6%. Conclusion The model can easily predict whether the pollution for decoration exceeds the standard and how long the room is decorated.

  14. Investigation of the Indoor Environment in a Passive House Apartment Building Heated by Ventilation Air

    OpenAIRE

    Lysholt Hansen, MathiasYoung Bok; Koulani, Chrysanthi Sofia; Peuhkuri, Ruut Hannele; Toftum, Jørn

    2014-01-01

    Experience has shown that appropriate design of very low energy dwellings can be a large challenge and that the final design may result in insufficient heating in winter and overheating in summer. The 126 certified Passive House apartments (Ravnsborghusene) in Køge, Denmark are a low energy building project finished medio 2012. The design challenge was met with a concept of air heating that is individually controlled in every room. It also applies external solar shading. This study used indoo...

  15. Ventilation rates and health

    DEFF Research Database (Denmark)

    Sundell, Jan; Levin, H; Nazaroff, W W

    2011-01-01

    The scientific literature through 2005 on the effects of ventilation rates on health in indoor environments has been reviewed by a multidisciplinary group. The group judged 27 papers published in peer-reviewed scientific journals as providing sufficient information on both ventilation rates...... and health effects to inform the relationship. Consistency was found across multiple investigations and different epidemiologic designs for different populations. Multiple health endpoints show similar relationships with ventilation rate. There is biological plausibility for an association of health outcomes...... studies of the relationship between ventilation rates and health, especially in diverse climates, in locations with polluted outdoor air and in buildings other than offices. PRACTICAL IMPLICATIONS: Ventilation with outdoor air plays an important role influencing human exposures to indoor pollutants...

  16. 燃料稀释对传统型和高预热空气稀释型燃烧炉性能的影响的数值研究%Numerical Investigation of Fuel Dilution Effects on the Performance of the Conventional and the Highly Preheated and Diluted Air Combustion Furnaces

    Institute of Scientific and Technical Information of China (English)

    Kiomars Abbasi Khazaei; Ali Asghar Hamidi; Masoud Rahimi

    2009-01-01

    This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N_2) in an industrial furnace under several cases of conventional combustion (air with 21% O_2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O_2 and 90% N_2) combustion (HPDAC) conditions using an in-house computer program. It was found that by applying a combined diluted fuel and oxidant instead of their un-combined and/or undiluted states, the best condition is obtained for the establishment of HPDAC's main unique features. These features are low mean and maximum gas temperature and high radiation/total heat transfer to gas and tubes; as well as more uniformity of theirs distributions which results in decrease in NO_x pollutant formation and increase in furnace efficiency or energy saving. Moreover, a variety of chemical flame shape, the process fluid and tubes walls temperatures profiles, the required regenerator efficiency and finally the concentration and velocity patterns have been also qualitatively/quantitatively studied.

  17. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.; Walker, Iain S.

    2011-04-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outdoor pollutant levels are high, the importance of minimizing energy use particularly during times of peak electricity demand, and how the energy used to condition air as part of ventilation system operation changes with outdoor conditions. Dynamic control of ventilation systems can provide ventilation equivalent to or better than what is required by standards while minimizing energy costs and can also add value by shifting load during peak times and reducing intake of outdoor air contaminants. This article describes the logic that enables dynamic control of whole-house ventilation systems to meet the intent of ventilation standards and demonstrates the dynamic ventilation system control concept through simulations and field tests of the Residential Integrated Ventilation-Energy Controller (RIVEC).

  18. [Collecting end-expiratory air for capnography in high-frequency jet ventilation].

    Science.gov (United States)

    Rockemann, M G; Doehn, M

    1985-04-01

    By means of an ejector attachment to the endotracheal tube a negative intratracheal pressure of approx. -1 mmHg is created during an interruption of HFJV. Within 4 to 10 sec. this suction supplies alveolar air to the distal end of the endotracheal tube where capnographic analysis is possible in the mainstream or bystream. The end-tidal pCO2 differs by 0.1 mmHg (mean) from the arterial carbon dioxide partial pressure with a highly positive correlation (R = 0.98).

  19. 谈暖通空调节能问题%On energy-saving issues in heat-supply and ventilation air-conditioners

    Institute of Scientific and Technical Information of China (English)

    张志宇

    2016-01-01

    The paper introduces the meanings in the energy-saving design of heat-supply and ventilation air-conditioners,illustrates the design methods from the heat-supply,ventilation and air-conditioners,and sums up the precautions in the energy-saving design,so as to improve the u-tility ratio of the resources and enhance the extension of the energy-saving technique.%介绍了暖通空调节能设计的意义,从供暖、通风、空调三方面,阐述了暖通空调节能设计的方法,总结了节能设计中的注意事项,有利于提高能源的利用率,促进节能技术的推广应用。

  20. Comparison of methods to evaluate the fungal biomass in heating, ventilation, and air-conditioning (HVAC) dust.

    Science.gov (United States)

    Biyeyeme Bi Mve, Marie-Jeanne; Cloutier, Yves; Lacombe, Nancy; Lavoie, Jacques; Debia, Maximilien; Marchand, Geneviève

    2016-12-01

    Heating, ventilation, and air-conditioning (HVAC) systems contain dust that can be contaminated with fungal spores (molds), which may have harmful effects on the respiratory health of the occupants of a building. HVAC cleaning is often based on visual inspection of the quantity of dust, without taking the mold content into account. The purpose of this study is to propose a method to estimate fungal contamination of dust in HVAC systems. Comparisons of different analytical methods were carried out on dust deposited in a controlled-atmosphere exposure chamber. Sixty samples were analyzed using four methods: culture, direct microscopic spore count (DMSC), β-N-acetylhexosaminidase (NAHA) dosing and qPCR. For each method, the limit of detection, replicability, and repeatability were assessed. The Pearson correlation coefficients between the methods were also evaluated. Depending on the analytical method, mean spore concentrations per 100 cm(2) of dust ranged from 10,000 to 682,000. Limits of detection varied from 120 to 217,000 spores/100 cm(2). Replicability and repeatability were between 1 and 15%. Pearson correlation coefficients varied from -0.217 to 0.83. The 18S qPCR showed the best sensitivity and precision, as well as the best correlation with the culture method. PCR targets only molds, and a total count of fungal DNA is obtained. Among the methods, mold DNA amplification by qPCR is the method suggested for estimating the fungal content found in dust of HVAC systems.

  1. Coal-packed methane biofilter for mitigation of green house gas emissions from coal mine ventilation air.

    Science.gov (United States)

    Limbri, Hendy; Gunawan, Cindy; Thomas, Torsten; Smith, Andrew; Scott, Jason; Rosche, Bettina

    2014-01-01

    Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min-1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m-3 empty bed h-1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min-1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.

  2. Coal-packed methane biofilter for mitigation of green house gas emissions from coal mine ventilation air.

    Directory of Open Access Journals (Sweden)

    Hendy Limbri

    Full Text Available Methane emitted by coal mine ventilation air (MVA is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min-1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m-3 empty bed h-1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min-1 (2.4 min empty bed residence time. These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.

  3. Coal-Packed Methane Biofilter for Mitigation of Green House Gas Emissions from Coal Mine Ventilation Air

    Science.gov (United States)

    Limbri, Hendy; Gunawan, Cindy; Thomas, Torsten; Smith, Andrew; Scott, Jason; Rosche, Bettina

    2014-01-01

    Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min−1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m−3 empty bed h−1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min−1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane. PMID:24743729

  4. Systems with centralized ventilation. Examples and applications. Air conditioning with regard to VDI 3804; Systeme mit zentraler Lueftung. Beispiele und Anwendungen. Raumklimatisierung nach VDI 3804

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2013-06-15

    Well coordinated, holistically designed ventilation and air-conditioning systems in the commercial sector increasingly gain in importance. Engineers and technicians have now to choose from a seemingly immense variety of available components. A good planning assistance and decision support are provided by the revised VDI guideline 3804 which describes six system combinations and thus defines the state of the art in this scope of application.

  5. Assessment of the potential of roof turbine ventilators for bathroom ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Ishiow Kuo [National United Univ., Dept. of Architecture, Miao-li City (Taiwan); Chiming Lai [Leader Univ., Dept. of Construction Technology, Tainan City (Taiwan)

    2005-06-15

    This study set out to investigate the potential of installing a new common roof turbine ventilator on to an existing bathroom ventilation system which serves 14 bathrooms in the first dormitory block of Leader University in Taiwan, and evaluate the overall ventilation performance of this new combination. Field measurements of airflow in the ventilation ducts and low-speed wind tunnel experiments for this turbine ventilator were carried out. The results showed that the combination of the roof turbine ventilator and bathroom ventilation were successful in achieving sufficient air change rate in bathrooms, and this ventilation design alternative is now proposed as a method of improving the indoor air environment in bathrooms. (Author)

  6. Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

    CERN Document Server

    2012-01-01

    Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

  7. Forced circulation air coolers with internally finned tubes; Ventilator-Luftkuehler mit innenberippten Rohren

    Energy Technology Data Exchange (ETDEWEB)

    Arnemann, M. [Forschungszentrum fuer Kaelte- und Umwelttechnik GmbH (FKU), Berlin (Germany)

    1998-04-01

    Tubes with internal fins have a much higher heat transfer during evaporation as compared with unfinned tubes. The findings served as a basis for the new development of the ``FHV high-performance forced circulation air cooler`` by Walter Roller GmbH and Co. The new evaporator type was designed on the basis of DIN 8955 and ENV 328 for evaporation temperatures of 0 C to -31 C. (orig.) [Deutsch] Im Vergleich zu glatten Rohren laesst sich durch den Einsatz von innenberippten Rohren der innere Waermeuebergang bei der Verdampfung nachweislich deutlich verbessern. Die Ergebnisse bildeten die Grundlage fuer die Neuentwicklung `FHV Hochleistungs-Luftkuehler` im Hause Walter Roller GmbH and Co. Die energetische Bewertung des neuen Verdampfertyps erfolgte in Anlehnung an die Normen DIN 8955 bzw. ENV 328 fuer Verdampfungstemperaturen zwischen 0 C und -31 C. (orig.)

  8. Why We Ventilate

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  9. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D. N.; Nielsen, Peter Vilhelm

    2001-01-01

    Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order...... to ensure that the ventilation system meets the demands it is important to know which parameters that influence the performance of the system. In this work the mixing ventilation principle was investigated. When the mixing ventilation principle is used for the design of a ventilation system it is assumed...

  10. Preoperational test report, vent building ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  11. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D.N.; Nielsen, Peter V.

    2001-01-01

    Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order to e...

  12. Aspects of wave turbulence in preheating

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Henrique P. de; Crespo, Jose A. de A. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Full text: In the simplest chaotic inflationary model, the Universe has an exponentially fast expansion phase driven by a single scalar field. After inflation, the preheating phase takes place. This phase is characterized when the inflaton performs coherent oscillations about its minimum value and is followed by a huge production of particles. In other terms, there is an energy transfer to small inhomogeneous fluctuations of the inflaton field. The long term behavior ends up in a thermalized universe. In this paper, we have studied numerically the late stages of preheating in a model with a quartic potential V (ϕ) = ¼λ ϕ{sup 4}. We have considered the universe as a squared box with periodic boundary conditions, and applied the collocation method to integrate the field equations. We have shown that the dynamics of the inflaton together with its initially small fluctuations is extremely rich. In the first stage, the parametric resonance is responsible for the exponential growth of some modes. In the sequence, the back reaction of these resonant modes triggers the transfer of energy to other modes or fluctuations. Subsequently, the transfer of energy from the inflaton to thermalize the universe is typical of a turbulent system. In the last part, we have considered the back reaction of the inflaton field in the expansion of the universe. (author)

  13. Experimental study on preheated combustion of pulverized semi-coke

    Science.gov (United States)

    Yao, Yao; Zhu, Jianguo; Lu, Qinggang; Zhou, Zuxu

    2015-06-01

    In a test rig, pulverized semi-coke was preheated to 850oC in a circulating fluidized bed (CFB) and then combusted at 1100oC in a down-fired combustor (DFC). Experiments were conducted to reveal the effects of three secondary air nozzle cases (co-axial jet, top circular jet and wall circular jet) on the NO emission. The results show that the optimized secondary air nozzle can reduce NO emission. O2 concentration profile is the major factor affecting NO generation and emission, which is led by the secondary air nozzle. The lower O2 concentration led to the generation of lower initial NO. The NO emission at the exit of the DFC was reduced from 189 to 92 mg/m3 (@ 6% O2) with the decrease of initial generation. The peak of NO at 100 mm below the nozzle should be attributed to the oxidization of NH3 in the syngas, rather than the oxidization of fuel-N in the char. The low and well-distributed O2 concentration contributes to the reduction of initial NO, which helps to reduce the NO emission. The combustion efficiencies of the cases of the co-axial jet, the top circular jet, and the wall circular jet are 97.88%, 98.94% and 98.74%, respectively.

  14. Validation of the criteria for initiating the cleaning of heating, ventilation, and air-conditioning (HVAC) ductwork under real conditions.

    Science.gov (United States)

    Lavoie, Jacques; Marchand, Geneviève; Cloutier, Yves; Lavoué, Jérôme

    2011-08-01

    Dust accumulation in the components of heating, ventilation, and air-conditioning (HVAC) systems is a potential source of contaminants. To date, very little information is available on recognized methods for assessing dust buildup in these systems. The few existing methods are either objective in nature, involving numerical values, or subjective in nature, based on experts' judgments. An earlier project aimed at assessing different methods of sampling dust in ducts was carried out in the laboratories of the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST). This laboratory study showed that all the sampling methods were practicable, provided that a specific surface-dust cleaning initiation criterion was used for each method. However, these conclusions were reached on the basis of ideal conditions in a laboratory using a reference dust. The objective of this present study was to validate these laboratory results in the field. To this end, the laboratory sampling templates were replicated in real ducts and the three sampling methods (the IRSST method, the method of the U.S. organization National Air Duct Cleaner Association [NADCA] and that of the French organization Association pour la Prévention et l'Étude de la Contamination [ASPEC]) were used simultaneously in a statistically representative number of systems. The air return and supply ducts were also compared. Cleaning initiation criteria under real conditions were found to be 6.0 mg/100 cm(2) using the IRSST method, 2.0 mg/100 cm(2) using the NADCA method, and 23 mg/100 cm(2) using the ASPEC method. In the laboratory study, the criteria using the same methods were 6.0 for the IRSST method, 2.0 for the NADCA method, and 3.0 for the ASPEC method. The laboratory criteria for the IRSST and NADCA methods were therefore validated in the field. The ASPEC criterion was the only one to change. The ASPEC method therefore allows for the most accurate evaluation of dust accumulation in HVAC

  15. Preheating Cold Gas Thruster Flow Through a Thermal Energy Storage Conversion System

    Science.gov (United States)

    2013-01-01

    Journal Article 3. DATES COVERED (From - To) January 2013- October 2013 4. TITLE AND SUBTITLE Preheating Cold Gas Thruster Flow Through a Thermal Energy... Gas Thruster Flow through a Thermal Energy Storage Conversion System Michael R. Reid1 United States Air Force, Colorado Springs, CO, 80840 David B...specific impulse relative to a cold gas flow. Electric propulsion systems, the primary competitor to solar thermal propulsion systems, rely on the rather

  16. Experimental data and boundary conditions for a Double - Skin Facade building in preheating mode

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Jensen, Rasmus Lund

    was carried out in a full scale test facility ‘The Cube’, in order to compile three sets of high quality experimental data for validation purposes. The data sets are available for preheating mode, external air curtain mode and transparent insulation mode. The objective of this article is to provide the reader......’. This covers such problem areas as measurements of naturally induced air flow, measurements of air temperature under direct solar radiation exposure, etc. Finally, in order to create a solid foundation for software validation, the uncertainty and limitations in the experimental results are discussed. In part...

  17. Ions Preheated in 3He-Rich Solar Particle Events

    Institute of Scientific and Technical Information of China (English)

    王德焴

    2003-01-01

    A wave-particle resonance absorption model in the two-ion plasma is suggested in explanation to the coronal ions preheating in 3He-rich solar particle events. It is found that 3He and Fe ions are preferably preheated by the ion-ion hybrid waves at their fundamental and second harmonic ion cyclotron frequencies, respectively.

  18. DEMAND CONTROLLED VENTILATION AND CLASSROOM VENTILATION

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling. Major findings included: ? The single-location carbon dioxide sensors widely used for demand controlled ventilation frequently have large errors and will fail to effectively control ventilation rates (VRs).? Multi-location carbon dioxide measurement systems with more expensive sensors connected to multi-location sampling systems may measure carbon dioxide more accurately.? Currently-available optical people counting systems work well much of the time but have large counting errors in some situations. ? In meeting rooms, measurements of carbon dioxide at return-air grilles appear to be a better choice than wall-mounted sensors.? In California, demand controlled ventilation in general office spaces is projected to save significant energy and be cost effective only if typical VRs without demand controlled ventilation are very high relative to VRs in codes. Based on the research, several recommendations were developed for demand controlled ventilation specifications in the California Title 24 Building Energy Efficiency Standards.The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA). Major findings included: ? Median classroom VRs in all studied climate zones were below the California guideline, and 40percent lower in portable than permanent buildings.? Overall, one additional L/s per person of VR was associated with 1.6percent less IA. ? Increasing average VRs in California K-12 classrooms from the current average to the required level is estimated to decrease IA by 3.4percent, increasing State attendance-based funding to school districts by $33M, with $6.2 M in increased energy costs. Further VR increases would provide additional benefits

  19. Ventilation in Commercial and Residential Buildings

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    A number of areas have to be considered in connection with indoor air quality and ventilation. The selection of ventilation principle and components in the ventilation system will have influence on the indoor air quality and this subject will be discussed on the following pages. The main object o...

  20. Fate of Electroweak Vacuum during Preheating

    CERN Document Server

    Ema, Yohei; Nakayama, Kazunori

    2016-01-01

    Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible dynamics that might relax them.

  1. QUENCH STUDIES AND PREHEATING ANALYSIS OF SEAMLESS

    Energy Technology Data Exchange (ETDEWEB)

    Palczewski, Ari [JLAB; Geng, Rongli [JLAB; Eremeev, Grigory [JLAB

    2013-09-01

    One of the alternative manufacturing technologies for SRF cavities is hydroforming from seamless tubes. Although this technology has produced cavities with gradient and Q-values comparable to standard EBW/EP cavities, a few questions remain. One of these questions is whether the quench mechanism in hydroformed cavities is the same as in standard electron beam welded cavities. Towards this effort Jefferson Lab performed quench studies on 2 9 cell seamless hydroformed cavities. These cavities include DESY's - Z163 and Z164 nine-cell cavities hydroformed at DESY. Initial Rf test results Z163 were published in SRF2011. In this report we will present post JLAB surface re-treatment quench studies for each cavity. The data will include OST and T-mapping quench localization as well as quench location preheating analysis comparing them to the observations in standard electron beam welded cavities.

  2. 智能气调和智能通风系统应用试验%Test on Application of Intelligent Air-conditioning and Intelligent Ventilation System

    Institute of Scientific and Technical Information of China (English)

    闻小龙; 张来林; 汪旭东; 张晓培; 邓谦; 李春水

    2012-01-01

    Intelligent air-conditioning system can detect air tightness in the silo automatically, and conduct storage by filling nitrogen and lowering oxygen timely and accurately in many manners, such as air charging in the upper or the lower or negative pressure air charging, etc. according to the actual oxygen density in the silo. Intelligent ventilation system, based on measurement and control of grain and combined with artificial work, opens and closes windows and fans automatically according to external temperature and humidity and temperature and humidity on grain heap surface, basically achieving intelligent ventilation.%智能气调系统能自动检测仓内气密性,并根据仓内的氧气浓度情况,及时准确的采用上充气、下充气或负压充气等多种形式进行富氮低氧储存。智能通风系统在人工结合粮情测控的基础上,根据外温外湿和粮堆表面的温湿度,自动开关窗口和风机,基本实现智能通风。

  3. VENTILATION MODEL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  4. Lecture Notes on Mixing Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The main task of the ventilation system or the air-conditioning system is to supply· and remove air and airborne materials and to supply or remove heat from a room. The necessary level of fresh air will be supplied to· a room by a ventilation system, and heat from equipment or solar radiation can...... be removed by an air-conditioning system. An industrial ventilation system may both take care of the occupants' comfort and the industrial processes in the area....

  5. EFFECT OF STORAGE, PRE-HEATING AND TURNING DURING HOLDING PERIOD ON THE HATCHABILITY OF BROILER BREEDER EGGS

    Directory of Open Access Journals (Sweden)

    A. MAHMUD AND T. N. PASHA1

    2008-07-01

    Full Text Available Two hundred forty fertile eggs of an average weight of 52-55g were taken from 32 weeks old broiler breeder flock. These eggs were divided into four groups i.e. A (Without turning and preheating, B (No turning but preheated, C (Turned but without preheating, and D (given both treatments preheating and turning with 60 eggs in each group. The eggs were stored with broad end upward at 16-20°C and 65-75% humidity. After storage for 5 days, the pre-heating of eggs of groups B and D was performed in an incubator where hot air at 30°C temperature was circulated for 6-7 hours to provide gradual warmth to the eggs before setting in the same incubator. The temperature of the incubator was maintained at 37.6°C with relative humidity of 70%. The eggs of groups C and D were turned on hourly basis at an angle of about 45° till 17 days of incubation. The hatchability values of eggs of groups A, B, C and D were 88.30 ± 0.30, 76.30 ± 0.30, 83.30 ± 0.30 and 79.90 ± 0.10%, respectively. Statistical analysis of the data by Chi-square test showed non-significant differences among treatments.

  6. Functionality of Ventilated Facades: Protection of Insulation

    OpenAIRE

    Petrichenko Mikhail; Musorina Tatiana; Statsenko Elena; Ostrovaia Anastasia; Tarasov Vladimir

    2016-01-01

    This article discusses about methods of construction of the ventilated facades. The ventilated facade is not only the element of facing, it is the supporting structure. Their main objective - creation of air ventilating space between a facade and an external wall of the building. Moving of air in this gap protects a heater from destruction, interfering with a moisture congestion. In addition, the ventilated facade protect the building from aggressive influence of external environment, have a ...

  7. Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings - Guideline of the German Society for Hospital Hygiene (DGKH).

    Science.gov (United States)

    Külpmann, Rüdiger; Christiansen, Bärbel; Kramer, Axel; Lüderitz, Peter; Pitten, Frank-Albert; Wille, Frank; Zastrow, Klaus-Dieter; Lemm, Friederike; Sommer, Regina; Halabi, Milo

    2016-01-01

    Since the publication of the first "Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems) in hospitals" (http://www.krankenhaushygiene.de/informationen/fachinformationen/leitlinien/12) in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section "Ventilation and air conditioning technology" attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

  8. Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings – Guideline of the German Society for Hospital Hygiene (DGKH)

    Science.gov (United States)

    Külpmann, Rüdiger; Christiansen, Bärbel; Kramer, Axel; Lüderitz, Peter; Pitten, Frank-Albert; Wille, Frank; Zastrow, Klaus-Dieter; Lemm, Friederike; Sommer, Regina; Halabi, Milo

    2016-01-01

    Since the publication of the first “Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems) in hospitals” (http://www.krankenhaushygiene.de/informationen/fachinformationen/leitlinien/12) in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section “Ventilation and air conditioning technology” attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care. PMID:26958457

  9. Development of the CELVA-1D code to evaluate the safety of an air-ventilation system during postulated fire and explosion in the reprocessing plant. Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Gunji; Watanabe, Kouji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kouno, Kouji; Yamazaki, Noboru; Mukaide, Shigeo; Yoshioka, Itsuo

    1998-03-01

    The CELVA-1D computer code was developed to evaluate the confinement of radioactive materials during postulated fire and explosion in a cell of nuclear fuel reprocessing plants. The CELVA-1D code calculates a response of temperature, pressure, flow velocity of fluid in an air-ventilation system of the plants by one-dimensional thermofluid analysis and calculates an ability to confine radioactive aerosol particles by transport, deposition, and HEPA filtration. The mathematical models in CELVA-1D were verified by comparison of the calculation with the result of JAERI`s demonstration tests simulating hypothetical fire and explosion accidents in the cell. (author)

  10. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    -cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...... is not well structured with this system. These become the motivations in developing the design guide. This design guide aims to establish a systematic understanding of diffuse ceiling ventilation and provide assistance in designing of such a system. The guide is targeted at design engineers, architects...... and manufacturers and the users of diffuse ceiling technology. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation. It provides an overview of potential benefit and limitations of this technology. The benefits include high thermal comfort, high...

  11. Pretest Predictions for Ventilation Tests

    Energy Technology Data Exchange (ETDEWEB)

    Y. Sun; H. Yang; H.N. Kalia

    2007-01-17

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that can be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only.

  12. Hill crossing during preheating after hilltop inflation

    CERN Document Server

    Antusch, Stefan; Orani, Stefano

    2015-01-01

    In 'hilltop inflation', inflation takes place when the inflaton field slowly rolls from close to a maximum of its potential (i.e. the 'hilltop') towards its minimum. When the inflaton potential is associated with a phase transition, possible topological defects produced during this phase transition, such as domain walls, are efficiently diluted during inflation. It is typically assumed that they also do not reform after inflation, i.e. that the inflaton field stays on its side of the 'hill', finally performing damped oscillations around the minimum of the potential. In this paper we study the linear and the non-linear phases of preheating after hilltop inflation. We find that the fluctuations of the inflaton field during the tachyonic oscillation phase grow strong enough to allow the inflaton field to form regions in position space where it crosses 'over the top of the hill' towards the 'wrong vacuum'. We investigate the formation and behaviour of these overshooting regions using lattice simulations: Rather t...

  13. Application of the Separate Universe Approach to Preheating

    CERN Document Server

    Tanaka, T; Tanaka, Takahiro; Bassett, Bruce

    2003-01-01

    The dynamics of preheating after inflation has not been clearly understood yet.In particular, the issue of the generation of metric perturbations during preheating on super-horizon scale is still unsettled. Large scale perturbations may leave an imprint on the cosmic microwave background, or may become seeds for generation of primordial black holes. Hence, in order to make a connection between the particle physics models and cosmological observations, understanding the evolution of super-Hubble scale perturbations during preheating is important. Here, we propose an alternative treatment to handle this issue based on the so-called separate universe approach, which suggests less efficient amplification of super-Hubble modes during preheating than was expected before. We also point out an important issue which may have been overlooked in previous treatments.

  14. Equation of state and Beginning of Thermalization After Preheating

    CERN Document Server

    Podolsky, D I; Kofman, L; Peloso, M; Podolsky, Dmitry I.; Felder, Gary N.; Kofman, Lev; Peloso, Marco

    2006-01-01

    We study the out-of-equilibrium nonlinear dynamics of fields after post-inflationary preheating. During preheating, the energy in the homogeneous inflaton is exponentially rapidly transfered into highly occupied out-of-equilibrium inhomogeneous modes, which subsequently evolve towards equilibrium. The infrared modes excited during preheating evolve towards a saturated distribution long before thermalization completes. We compute the equation of state during and immediately after preheating. It rapidly evolves towards radiation domination long before the actual thermal equilibrium is established. The exact time of this transition is a non-monotonic function of the coupling between the inflaton and the decay products, and it varies only very weakly (around 10^(-35) s) as this coupling changes over several orders of magnitude. This result is applied to refine the relation between the number of efoldings N and the physical wavelength of perturbations generated during inflation. We also discuss the implications fo...

  15. Anisotropies in the gravitational wave background from preheating.

    Science.gov (United States)

    Bethke, Laura; Figueroa, Daniel G; Rajantie, Arttu

    2013-07-05

    We investigate the anisotropies in the gravitational wave (GW) background produced at preheating after inflation. Using lattice field theory simulations of a massless preheating model, we show that the GW amplitude depends sensitively on the value of the decay product field χ coupled to the inflaton φ, with the only requisite that χ is light during inflation. We find a strong anisotropy in the amplitude of the GW background on large angular scales, the details of which strongly depend on the reheating dynamics. We expect similar conclusions for a wide class of inflationary models with light scalar fields. If future direct detection GW experiments are capable of detecting the GW produced by preheating, they should also be able to detect this effect. This could eventually provide a powerful way to distinguish between different inflationary and preheating scenarios.

  16. Plane Stratified Flow in a Room Ventilated by Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Nickel, J.; Baron, D. J. G.

    2004-01-01

    The air movement in the occupied zone of a room ventilated by displacement ventilation exists as a stratified flow along the floor. This flow can be radial or plane according to the number of wall-mounted diffusers and the room geometry. The paper addresses the situations where plane flow...

  17. Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores and other commercial buildings in California. Issues related to the ASHRAE 62.1 Indoor Air Quality Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Apte, Mike G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2010-10-31

    This report considers the question of whether the California Energy Commission should incorporate the ASHRAE 62.1 ventilation standard into the Title 24 ventilation rate (VR) standards, thus allowing buildings to follow the Indoor Air Quality Procedure. This, in contrast to the current prescriptive standard, allows the option of using ventilation rate as one of several strategies, which might include source reduction and air cleaning, to meet specified targets of indoor air concentrations and occupant acceptability. The research findings reviewed in this report suggest that a revised approach to a ventilation standard for commercial buildings is necessary, because the current prescriptive ASHRAE 62.1 Ventilation Rate Procedure (VRP) apparently does not provide occupants with either sufficiently acceptable or sufficiently healthprotective air quality. One possible solution would be a dramatic increase in the minimum ventilation rates (VRs) prescribed by a VRP. This solution, however, is not feasible for at least three reasons: the current need to reduce energy use rather than increase it further, the problem of polluted outdoor air in many cities, and the apparent limited ability of increasing VRs to reduce all indoor airborne contaminants of concern (per Hodgson (2003)). Any feasible solution is thus likely to include methods of pollutant reduction other than increased outdoor air ventilation; e.g., source reduction or air cleaning. The alternative 62.1 Indoor Air Quality Procedure (IAQP) offers multiple possible benefits in this direction over the VRP, but seems too limited by insufficient specifications and inadequate available data to provide adequate protection for occupants. Ventilation system designers rarely choose to use it, finding it too arbitrary and requiring use of much non-engineering judgment and information that is not readily available. This report suggests strategies to revise the current ASHRAE IAQP to reduce its current limitations. These

  18. Evaluation of Local Exhaust Ventilation Efficiency to Control Emissions of Fe2O3 Dust in Ambient Air of the Oxide Screen Unit in steel industry

    Directory of Open Access Journals (Sweden)

    Mahdi Jamshidi Rastani

    2015-10-01

    Full Text Available Introduction: There are numerous strategies to reduce of workers' exposure to chemical pollutants and control of emitted pollutants. Local exhaust ventilation (LEV is most common equipment for engineering controls that is more preferred than other control methods. The aim of this study was to determine efficiency of LEV to control emissions dust in ambient air of a screen unit of steel industry. Methods: This is a descriptive study and in order evaluate efficiency of LEV, the screen unit divided into four parts including: ground floor, floor screen, hood 1 floor and platform hoods 15, 16, 17. The 36 air samples collected with the method of NIOSH -600 (cyclone samplers were used to conduct both respirable and total dust sampling in the ON & OFF mode of ventilation system. Results: The results showed that the first floor had highest concentration with an average and range of 271.3 (118.1-434.47 mg/m3 (Approximately 18.2 times the PEL-OSHA and its control efficiency was 3.9%. The lowest concentration was found at the screen floor with the average and range of 20.77 (8.95-31.51mg/m3 (Approximately1.4 times the PEL-OSHA and also its efficiency for ventilation in ''ON'' mode was 29.35 %. The average and range of concentration and overall efficiency in whole of the unit were found to be 127.6 (20.77-234.63 mg/m3 and 7.96 %, respectively. (TLV-ACGIH:10mg/m3, PEL-OSHA: 15mg/m3 Conclusion: In this study the efficiency of the system was different in different parts and LEV had not appropriate efficiency, which could be attributable to lack of regular and scheduled system for maintenance and monitoring of LEV and also change of production rates.

  19. Noise control in air blower of laboratory ventilation system%实验室通风系统风机噪声的综合治理

    Institute of Scientific and Technical Information of China (English)

    盖磊; 周东

    2012-01-01

    实验室通风系统在保证良好的室内空气质量的同时,往往会带来一定程度的噪声污染.济南市供排水监测中心综合实验室通风系统对室外环境造成了严重的噪声污染.文章对该实验室通风系统的噪声特性进行了测试与分析,结果表明:位于室外屋顶的风机为主要噪声源;阐述了针对风机噪声采用综合运用隔声罩、阻抗式消声器和隔声包扎等治理措施;提出了使用计算机模拟的方法用于噪声治理措施的选择与评价.项目竣工后,其噪声污染已控制到国家允许标准以下.%Laboratory ventilation system can usually ensure good indoor air quality, but at the same time it often brings a certain degree of noise pollution. The laboratory ventilation system of Jinan Water and Waste Water Monitoring Center had polluted the environment seriously. In this paper, the noise from the laboratory ventilation system was tested and analyzed. The results showed that the air blower which was located on the roof was the main noise source. Then some corresponding control measures, such as installing acoustical enclosure, silencer and sound insulation enswathement, were put forward and implemented. It also used computer simulation methods for noise control measures in the selection and evaluation. As those measures were taken, the noise level at the boundary was reduced to the quality standard.

  20. Gauge Field Preheating at the End of Inflation

    CERN Document Server

    Deskins, J Tate; Caldwell, Robert R

    2013-01-01

    Here we consider the possibility of preheating the Universe via the parametric amplification of a massless, U(1) abelian gauge field. We assume that the gauge field is coupled to the inflaton via a conformal factor with one free parameter. We present the results of high-resolution three-dimensional simulations of this model and show this mechanism efficiently preheats the Universe to a radiation-dominated final state.

  1. Thermal comfort of seated occupants in rooms with personalized ventilation combined with mixing or displacement ventilation

    DEFF Research Database (Denmark)

    Forejt, L.; Melikov, Arsen Krikor; Cermak, Radim

    2004-01-01

    The performance of two personalized ventilation systems combined with mixing or displacement ventilation was studied under different conditions in regard to thermal comfort of seated occupants. The cooling performance of personalized ventilation was found to be independent of room air distribution....... Differences between the personalized air terminal devices were identified in terms of the cooling distribution over the manikin¿s body. The personalized ventilation supplying air from the front towards the face provided a more uniform cooling of the body than the personalized ventilation supplying air from...

  2. Evolution of microbial aerosol behaviour in heating, ventilating and air-conditioning systems--quantification of Staphylococcus epidermidis and Penicillium oxalicum viability.

    Science.gov (United States)

    Forthomme, A; Andrès, Y; Joubert, A; Simon, X; Duquenne, P; Bemer, D; Le Coq, L

    2013-01-01

    The aim of this study was to develop an experimental set-up and a methodology to uniformly contaminate several filter samples with high concentrations of cultivable bacteria and fungi. An experimental set-up allows contaminating simultaneously up to four filters for range of velocities representative of heating, ventilating and air-conditioning systems. The test aerosol was composed of a microbial consortium of one bacterium (Staphylococcus epidermidis) and one fungus (Penicillium oxalicum) and aerosol generation was performed in wet conditions. Firstly, the experimental set-up was validated in regards to homogeneity of the air flows. The bioaerosol was also characterized in terms of number and particle size distribution using two particle counters: optical particle counter Grimm 1.109 (optical diameters) and TSI APS 3321 (aerodynamic diameters). Moreover, stabilities of the number of particles generated were measured. Finally, concentrations of cultivable microorganisms were measured with BioSamplers (SKC) downstream of the four filters.

  3. 某图书馆暖通空调系统设计分析%On heat-supply and ventilation air-conditioner system of some library

    Institute of Scientific and Technical Information of China (English)

    王秀山

    2016-01-01

    According to the design ideas for the library,from heat-supply and ventilation air-conditioner system,cold and heat source system,in-terior layout,professional cooperation and other aspects,the paper analyzes a series of problems in the heat-supply and ventilation air-conditioner of some library,and illustrates respective treatment measures,so as to create the comfortable reading environment with suitable temperature and humidity.%根据图书馆的设计理念,从暖通空调系统、冷热源系统、室内系统布置、专业配合等方面,分析了某图书馆暖通空调设计中存在的一系列问题,并阐述了相应的处理措施,旨在创造出温湿度适宜、环境清新的阅读环境.

  4. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    Directory of Open Access Journals (Sweden)

    S. Amos-Abanyie

    2013-01-01

    Full Text Available Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+ simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT. An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses.

  5. Ventilation and Heat Recovering System

    Directory of Open Access Journals (Sweden)

    Olga Bancea

    2007-01-01

    Full Text Available Some aspects concerning the heat reducing for ventilation, achieved by using heat recovering components and a combined heating--ventilating system, assuring both comfort and human health are presented. The floor imbedded systems together with air outlets elements could fulfill all the aesthetically desires, as well as comfort and they are ideal for family houses.

  6. Ventilation system design for educational facilities

    Energy Technology Data Exchange (ETDEWEB)

    Elsafty, A.F.; Abo Elazm, M.M. [Arab Academy for Science, Alexandria (Egypt). Technology and Maritime Transport; Safwan, M. [Arab Academy for Science, Cairo (Egypt). Technology and Maritime Transport

    2010-07-01

    In order to maintain acceptable indoor air quality levels in classrooms, high ventilation rates are needed to dilute the concentration of indoor contaminants, resulting in higher energy consumption for the operation of mechanical ventilation systems. Three factors are usually considered when determining the adequate ventilation rate for classrooms in educational facilities. These include the maximum population served in the classroom; carbon dioxide (CO{sub 2}) production rate by occupants; and outdoor air conditions. CO{sub 2} concentrations usually indicate the rate of ventilation required. This paper presented a newly developed computer software program for determining the ventilation rates needed to enhance indoor air quality and to maintain CO{sub 2} concentration within the recommended levels by ANSI/ASHRAE standards for best student performance. This paper also presented design curves for determining the ventilation rates and air changes per hour required for the ventilated educational zone. 15 refs., 2 tabs., 5 figs.

  7. Solar Air Collectors for Space Heating and Ventilation Applications—Performance and Case Studies under Romanian Climatic Conditions

    OpenAIRE

    Sanda Budea

    2014-01-01

    Solar air collectors have various applications: on the one hand, they can be used for air heating in cold seasons; on the other hand they can be used in summer to evacuate the warm and polluted air from residential, offices, industrial, and commercial buildings. The paper presents experimental results of a solar collector air, under the climatic conditions of the Southeastern Europe. The relationships between the direct solar irradiation, the resulting heat flow, the air velocity at the outle...

  8. Achieving Natural and Hybrid Ventilation in Practice

    DEFF Research Database (Denmark)

    Liddament, Martin; Axley, James; Heiselberg, Per

    2006-01-01

    to extend the range and climate in which such buildings can operate. These include pre conditioning the air using underground labyrinths or buried pipes, the inclusion of pre-heating and cooling coils, and the use of thermal mass combined with night cooling. Design and operational faults include incorrect...

  9. CFD and Ventilation Research

    DEFF Research Database (Denmark)

    Li, Y.; Nielsen, Peter V.

    2011-01-01

    There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000–10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part...... of scientific research and engineering development of complex air distribution and ventilation systems in buildings. This review discusses the major and specific challenges of CFD in terms of turbulence modelling, numerical approximation, and boundary conditions relevant to building ventilation. We emphasize...... the growing need for CFD verification and validation, suggest on-going needs for analytical and experimental methods to support the numerical solutions, and discuss the growing capacity of CFD in opening up new research areas. We suggest that CFD has not become a replacement for experiment and theoretical...

  10. Why this crisis in residential ventilation

    NARCIS (Netherlands)

    Hasselaar, E.

    2008-01-01

    Ventilation is the cornerstone of good indoor air quality. Ventilation requirements have major attention in building regulations, but ventilation in practice is often poor, resulting in increased concentration of pollutants and hence exposure to health risk. Inspection of 500 houses with interviews

  11. Demand Controlled Ventilation and Classroom Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davies, Molly [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Eliseeva, Ekaterina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hong, Tienzen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-05-01

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  12. Computational Fluid Dynamic Modeling of Horizontal Air-Ground Heat Exchangers (HAGHE for HVAC Systems

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2014-12-01

    Full Text Available In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB, innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe.

  13. Indoor air quality and occupant satisfaction in five mechanically and four naturally ventilated open-plan office buildings

    DEFF Research Database (Denmark)

    Hummelgaard, J.; Juhl, P.; Saebjornsson, K.O.

    2007-01-01

    afternoon. In a pre-experiment, temperature and the concentration Of CO2 were monitored in 2-10 locations/office to evaluate the variation throughout the offices. A representative measurement point was subsequently selected and measurements of the same parameters were made during one week. All offices were...... monitored during the same week and occupant responses to the indoor environment were collected via the internet on the same day within that week. The temperature and the CO2 concentration varied more and were in some cases higher in the naturally ventilated buildings, but occupant responses in terms...

  14. Use of CO2 feedback as a retrofit solution for improving air quality in naturally ventilated classrooms

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Faria Da Silva, Nuno Alexandre

    Carbon dioxide (CO2) sensors that provide a green/yellow/red visual indication were installed in pairs of naturally ventilated classrooms during normal school operation. During a two-week period in the heating and the cooling season, teachers and students were instructed to open the windows...... in these classrooms and window opening behaviour were monitored. Children also reported their perceptions and symptoms. Resulting energy use was measured and used to estimate annual energy use. Providing CO2 feedback reduced CO2 levels. More windows were opened in this condition, and this increased energy use...

  15. Summary of human responses to ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Seppanen, Olli A.; Fisk, William J.

    2004-06-01

    The effects of ventilation on indoor air quality and health is a complex issue. It is known that ventilation is necessary to remove indoor generated pollutants from indoor air or dilute their concentration to acceptable levels. But, as the limit values of all pollutants are not known, the exact determination of required ventilation rates based on pollutant concentrations and associated risks is seldom possible. The selection of ventilation rates has to be based also on epidemiological research (e.g. Seppanen et al., 1999), laboratory and field experiments (e.g. CEN 1996, Wargocki et al., 2002a) and experience (e.g. ECA 2003). Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated as summarized by Seppdnen (2003). Ventilation may bring indoors harmful substances that deteriorate the indoor environment. Ventilation also affects air and moisture flow through the building envelope and may lead to moisture problems that deteriorate the structures of the building. Ventilation changes the pressure differences over the structures of building and may cause or prevent the infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. Ventilation can be implemented with various methods which may also affect health (e.g. Seppdnen and Fisk, 2002, Wargocki et al., 2002a). In non residential buildings and hot climates, ventilation is often integrated with air-conditioning which makes the operation of ventilation system more complex. As ventilation is used for many purposes its health effects are also various and complex. This paper summarizes the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus of the paper is on office-type working environment and residential buildings. In the industrial premises the problems of air quality are usually

  16. Ventilation with heat recovery

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2005-01-01

    This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...

  17. Ventilation with heat recovery

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2005-01-01

    and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain......This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...

  18. DEVELOPMENT OF CONSTRUCTION OF A CATALYTIC REACTOR FOR METHANE OXIDISING IN VENTILATION AIR IN COAL MINES AND THE RESEARCH ON INTEGRATED “HEAT PIPE” RECUPERATOR

    Directory of Open Access Journals (Sweden)

    Lech Hys

    2013-04-01

    Full Text Available The article presents the analysis whose result is the selection of appropriate design and construction of a monolithic CMR reactor intended for oxidising methane from ventilation air in coal mines. The description of “heat-pipe” recuperator cooperating with the reactor was also presented. The research was mainly aimed at verifying the compliance with the work of autothermity premise obtained by the return of part of heat from catalytic reaction. The result of research was to define the range volumetric fume expense ensuring autothermity and the definition of maximum recuperator efficiency. The range of volumetric expense was 18–25 m3/h and maximum value of efficiency coefficient was η = 0.50 for the volumetric expense of 18 m3/h.

  19. Mechanical ventilation with heat recovery in cold climates

    DEFF Research Database (Denmark)

    Kragh, Jesper; Rose, Jørgen; Svendsen, Svend

    2005-01-01

    Building ventilation is necessary to achieve a healthy and comfortable indoor environment, but as energy prices continue to rise it is necessary to reduce the energy consumption. Using mechanical ventilation with heat recovery reduces the ventilation heat loss significantly, but in cold climates...... freezes to ice. The analysis of measurements from existing ventilation systems with heat recovery used in single-family houses in Denmark and a test of a standard heat recovery unit in the laboratory have clearly shown that this problem occurs when the outdoor temperature gets below approximately –5º......C. Due to the ice problem mechanical ventilation systems with heat recovery are often installed with an extra preheating system reducing the energy saving potential significantly. New designs of high efficient heat recovery units capable of continuously defrosting the ice without using extra energy...

  20. Reheating and preheating in the simplest extension of Starobinsky inflation

    CERN Document Server

    van de Bruck, C; Paduraru, L E

    2016-01-01

    The epochs of reheating and preheating are studied in a simple extension of the Starobinsky inflationary model, which consists of an $R^2$--correction to the Einstein--Hilbert action and an additional scalar field. We find that if the $R^2$--correction at the end of inflation is dynamically important, it affects the expansion rate and as a consequence the reheating and preheating processes. While we find that the reheating temperature and duration of reheating are only slightly affected, the effect has to be taken into account when comparing the theory to data. In the case of preheating, the gravitational corrections can significantly affect the decay of the second field. Particle production is strongly affected for certain values of the parameters in the theory.

  1. 成都某公司办公大楼空调通风设计%Air Conditioning and Ventilation System Design for A Company Office Building in ChengDu City

    Institute of Scientific and Technical Information of China (English)

    何朝烽

    2014-01-01

    The design of air conditioning , ventilation, smoke control and extraction system and air conditioning automatic control system for a company office building in ChengDu City were introduced .The form of air conditioning system was expounded .Fire prevention measure , energy conservation measure ,environmental protection and hygiene and disease control measure of air conditioning and ventilation systems were provided .%介绍了成都某公司办公大楼的空调、通风、防排烟系统和空调自动控制系统设计,详细阐述了空调系统形式,指出了通风空调系统防火措施、节能措施及环保与卫生防疫措施。

  2. Gravity Waves from Tachyonic Preheating after Hybrid Inflation

    CERN Document Server

    Dufaux, Jean Francois; Kofman, Lev; Navros, Olga

    2008-01-01

    We study the stochastic background of gravitational waves produced from preheating in hybrid inflation models. We investigate different dynamical regimes of preheating in these models and we compute the resulting gravity wave spectra using analytical estimates and numerical simulations. We discuss the dependence of the gravity wave frequencies and amplitudes on the various potential parameters. We find that large regions of the parameter space leads to gravity waves that may be observable in upcoming interferometric experiments, including Advanced LIGO, but this generally requires very small coupling constants.

  3. Formation of sub-horizon black holes from preheating

    CERN Document Server

    Torres-Lomas, E; Malik, Karim A; Ureña-López, L Arturo

    2014-01-01

    We study the production of primordial black holes (PBHs) during the preheating stage that follows a chaotic inflationary phase. The scalar fields present in the process are evolved numerically using a modified version of the HLATTICE code. From the output of the numerical simulation we compute the probability distribution of curvature fluctuations paying particular attention to sub-horizon scales. We find that in some specific models these modes grow to large amplitudes developing highly non-Gaussian probability distributions. We then calculate PBH abundances using the standard Press-Schechter criterion and find that overproduction of PBHs is likely in some regions of the chaotic preheating parameter-space.

  4. Ventilative Cooling

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Kolokotroni, Maria

    This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state-of-the-art of ventil......This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state...

  5. Measurement of air temperature in the presence of a large radiant flux: an assessment of passively ventilated thermometer screens

    Science.gov (United States)

    Erell, Evyatar; Leal, Vítor; Maldonado, Eduardo

    The energy balance of small temperature sensors was modelled to illustrate the effects of sensor characteristics, particularly size, on the accuracy of readings in the presence of strong shortwave or longwave radiant loads. For all but extremely small sensors, radiant exchange may lead to unacceptable errors. The common practice of using passively ventilated instrument screens was evaluated in a series of comparative measurements. The differences resulting from the use of different models of shields may be an order of magnitude greater than the error resulting from sensor calibration. In the absence of technological innovation capable of reducing the error due to radiant exchange to negligible proportions, it is suggested that a standard methodology for calibrating and labelling the error resulting from the characteristics of the screens be adopted, to allow comparison of new data with long-established records.

  6. Use of CO2 feedback as a retrofit solution for improving air quality in naturally ventilated classrooms

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Faria Da Silva, Nuno Alexandre

    Carbon dioxide (CO2) sensors that provide a green/yellow/red visual indication were installed in pairs of naturally ventilated classrooms during normal school operation. During a two-week period in the heating and the cooling season, teachers and students were instructed to open the windows...... in response to the CO2 feedback in one week and open them as they would normally do, without feedback, in the other week. In the cooling season, two pairs of classrooms were monitored, one pair with split cooling in operation and the other pair with no cooling. The resulting indoor environmental conditions...... in these classrooms and window opening behaviour were monitored. Children also reported their perceptions and symptoms. Resulting energy use was measured and used to estimate annual energy use. Providing CO2 feedback reduced CO2 levels. More windows were opened in this condition, and this increased energy use...

  7. Subsurface Ventilation System Description Document

    Energy Technology Data Exchange (ETDEWEB)

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  8. Subsurface Ventilation System Description Document

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  9. Performance of Ductless Personalized Ventilation in Conjunction with Displacement Ventilation: Impact of Workstations Layout and Partitions

    DEFF Research Database (Denmark)

    Halvonova, Barbara; Melikov, Arsen Krikor

    2010-01-01

    The performance of a new personalized ventilation system, referred to as ductless personalized ventilation (DPV), was studied in full-scale room experiments in conjunction with displacement ventilation (DV). The idea behind DPV is to utilize clean and cool air supplied via DV. In the experiment...

  10. Influence of fuel moisture, charge size, feeding rate and air ventilation conditions on the emissions of PM, OC, EC, parent PAHs, and their derivatives from residential wood combustion

    Institute of Scientific and Technical Information of China (English)

    Guofeng Shen; Miao Xue; Siye Wei; Yuanchen Chen; Qiuyue Zhao; Bing Li; Haisuo Wu

    2013-01-01

    Controlled combustion experiments were conducted to investigate the influence of fuel charge size,moisture,air ventilation and feeding rate on the emission factors (EFs) of carbonaceous particulate matter,parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove.Measured EFs were found to be independent of fuel charge size,but increased with increasing fuel moisture.Pollution emissions from the normal burning under an adequate air supply condition were the lowest for most pollutants,while more pollutants were emitted when an oxygen deficient atmosphere was formed in the stove chamber during fast burning.The impacts of these factors on the size distribution of emitted particles was also studied.Modified combustion efficiency and the four investigated factors explained 68%,72%,and 64% of total variations in EFs of PM,organic carbon,and oxygenated PAHs,respectively,but only 36%,38% and 42% of the total variations in EFs of elemental carbon,pPAHs and nitro-PAHs,respectively.

  11. 41 CFR 102-74.195 - What ventilation policy must Federal agencies follow?

    Science.gov (United States)

    2010-07-01

    ... provide ventilation in accordance with ASHRAE Standard 62, Ventilation for Acceptable Indoor Air Quality... ventilation up to current standards. ASHRAE Standard 62 is available from ASHRAE Publications Sales, 1791...

  12. Natural air ventilation in underground galleries as a tool to increase radon sampling volumes for geologic monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Eff-Darwich, Antonio [Departamento de Edafologia y Geologia, Universidad de La Laguna, Av. Astrofisico Francisco, Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Instituto de Astrofisica de Canarias, c/Via Lactea s/n, 38205 La Laguna, Tenerife (Spain)], E-mail: adarwich@ull.es; Vinas, Ronaldo [Departamento de Edafologia y Geologia, Universidad de La Laguna, Av. Astrofisico Francisco, Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Soler, Vicente [Estacion Volcanologica de Canarias, IPNA-CSIC, Av. Astrofisico Francisco Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Nuez, Julio de la; Quesada, Maria L. [Departamento de Edafologia y Geologia, Universidad de La Laguna, Av. Astrofisico Francisco, Sanchez s/n, 38206 La Laguna, Tenerife (Spain)

    2008-09-15

    A simple numerical model was implemented to infer airflow (natural ventilation) in underground tunnels from the differences in the temporal patterns of radon, {sup 222}Rn, concentration time-series that were measured at two distant points in the interior of the tunnels. The main purpose of this work was to demonstrate that the installation of radon monitoring stations closer to the entrance of the tunnels was sufficient to remotely analyse the distribution of radon concentration in their interiors. This could ease the monitoring of radon, since the effective sampling volume of a single monitoring station located closer to the entrance of a tunnel is approximately 30,000 times larger than the sampling volume of a sub-soil radon sensor. This methodology was applied to an underground gallery located in the volcanic island of Tenerife, Canary Islands. This island constitutes an ideal laboratory to study the geo-dynamical behaviour of radon because of the existence of a vast network of galleries that conforms the main water supply of the island.

  13. Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

    Science.gov (United States)

    Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

    2012-06-01

    In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

  14. Simulation and validation of the evaporation of water from liquid manure using ventilation exhaust air: linking of two simulation models.

    NARCIS (Netherlands)

    Wagenberg, van A.V.; Vranken, E.; Berckmans, D.

    2003-01-01

    The pig production needs to be modified into a sustainable system. Handling of the manure and reducing emissions have to be taken into account in the design of pig facilities, so the called integrated pig facilities are being developed in which the energy in the exhaust air can be used to evaporate

  15. Comparative study between LMA-Proseal™ and Air-Q® Blocker for ventilation in adult eye trauma patients

    Directory of Open Access Journals (Sweden)

    Maha M.I. Youssef

    2014-07-01

    Conclusion: The Air-Q® Blocker demonstrated to be remarkably good as a ventilatory device, with adequate airway seal pressure, and improved facilitation of gastric tube insertion compared to LMA-Proseal™. Minimal pressor response was achieved after insertion with no statistical significance.

  16. Development of energy-efficient comfortable ventilation systems with air quality guided volume flow control and continuous monitoring of the window opening status. Part 1. Use of the LuQaS triple sensor for air quality guided volume flow control of mechanical ventilation systems in domestic buildings. Research project; Entwicklung energieeffizienter Komfortlueftungsanlagen mit luftqualitaetsgefuehrter Volumenstromregelung und kontinuierlicher Erfassung des Fensteroeffnungszustandes. Teilbericht 1. Einsatz des LuQaS-Triple-Sensors zur luftqualitaetsgefuehrten Volumenstromregelung von mechanischen Lueftungsanlagen in Wohngebaeuden. Forschungsprojekt

    Energy Technology Data Exchange (ETDEWEB)

    Grossklos, Marc; Ebel, Witta; Knissel, Jens

    2011-05-15

    The report presents the preparatory work on the research project of the above title. The first chapter presents a status report on air quality monitoring inside rooms and evaluates the projects so far in which the LuQaS air quality sensor was used. The second chapter is a documentation of preliminary measurements using the LuQaS sensor in two passive residential buildings and several individual measurements for sensor calibration. It was found that in apartments with mechanical ventilation, the sensor reflects the user activities; further, the measured values indicate signal changes also in the off-air of the building, so that control via central sensors in the ventilation and off-air systems appears feasible. The third chapter discusses control strategies for air quality control. Apart from a discussion of control unit types, operating regimes, methods to determine rated values, and additional control functions, the effects of threshold value control with different threshold limit values and volume flow changes on the air quality of a model building was simulated. The results prove the expectation that the air quality inside a building will be influenced positively by air quality control. Theoretical investigations of the DrD method will be presented in another part-report of the project.

  17. ASHRAE and residential ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the

  18. Analysis of sodium experimental circuits pre-heating for the development of nuclear reactors; Analise do pre-aquecimento de circuitos experimentais a sodio para desenvolvimento de reatores nuclares

    Energy Technology Data Exchange (ETDEWEB)

    Bellini, Ione Walmir

    1995-09-01

    To satisfy the experimental requirements of sodium loops for nuclear reactors development, a preheating system, consisting of tubular haters, is analyzed. The tubular heaters are usually comprised of a nickel-chromium wire centered in a metal sheath and insulated by magnesium oxide. Practical and simplified methods for the preheating parameters calculations and for the heaters elements determination and section are presented. A thermal method to evaluate the sodium mass in a tank is presented, using the preheating system, when the tank geometry or the sodium level are unknown. The materials employed and the installation procedures of the preheating system are indicated. It is described a procedure, step, to make the connection between the electrical resistance and the conductor wire, to assure the heat dissipation and the air-tight of the heater element. Several suggestions are presented to clarify some doubts, to define correction factors, to develop technology, and to give continuity to the present work. (author). 37 refs., 22 figs.

  19. Design of Natural and Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    -energy approach. Natural ventilation can be used to provide fresh air for the occupants, necessary to maintain acceptable air quality levels, and to cool buildings in cases where the climatic conditions allow it. Natural ventilation is caused by pressure differences at the inlets and outlets of a building......The effectiveness of natural ventilation, i.e. its ability to ensure indoor air quality and passive cooling in a building, depends greatly on the design process. Mechanical ventilation systems can be designed separately from the design of the building in which they are installed. They can also...... be installed in existing buildings after a few modifications. In contrast, ventilation systems using only natural forces such as wind and thermal buoyancy need to be designed together with the building, since the building itself and its components are the elements that can reduce or increase air movement...

  20. 杜儿坪矿中部风井风排瓦斯氧化处理项目设计%The Design of Ventilation Air Methane Oxidation Treatment Project of

    Institute of Scientific and Technical Information of China (English)

    罗申国

    2013-01-01

    我国煤矿风排瓦斯量巨大,直接排放造成环境污染和能源浪费,利用乏风氧化机组将其销毁,同时产生热能,不仅改善大气环境,还为矿井风排瓦斯处理开辟了一条新途径。以杜儿坪矿中部风井风排瓦斯氧化处理项目设计为例,介绍了工程概况、机组选型、装机规模及工艺系统设计方案,并论述了避免对矿井通风安全造成影响的措施。%There is a huge number of coal mine ventilation air methane in China,emptying directly lead to envi-ronmental pollution and energy waste,using oxidation unit will be destroyed,and generate heat,not only improve the atmospheric environment,also for mine ventilation air methane treatment has opened up a new way.Takes the ventila-tion air methane oxidation treatment project design in Du'erping coal mine central ventilation shaft as an example,in-troduces the engineering general situation,the unit type selection,installed capacity and design scheme of process system,and discusses the measures to avoid affecting the safety of mine ventilation.

  1. Exposure to exhaled air from a sick occupant in a two-bed hospital room with mixing ventilation: effect of distance from sick occupant and air change rate

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Georgiev, Emanuil

    2011-01-01

    an exposed patient lying in the second bed. The doctor stood 0.55 m or 1.1 m facing the sick patient. The breathing mode of the “sick patient” was: exhalation mouth/inhalation nose. Tracer gas (R-134a) was mixed with the exhaled air. Important finding of this study is that airflow distribution...

  2. Bruce Unit 1 and 2 preheater condition assessment and refurbishment

    Energy Technology Data Exchange (ETDEWEB)

    King, P.; Machowski, C.; McGillivray, R. [Babcock and Wilcox Canada Ltd., Cambridge, ON (Canada); Durance, D. [Bruce Power, Tiverton, ON (Canada)

    2008-07-01

    Bruce Units 1 to 4 were shut down during the 1990s, largely as a consequence of tube degradation resulting from inappropriate steam generator secondary side water chemistries. Following a condition assessment, Bruce Power restarted Units 3 and 4 and is currently refurbishing Units 1 and 2. In order to assess the condition of the Unit 1 and Unit 2 preheaters and determine their suitability for extended operation, inspection, maintenance and assessment activities have been conducted. Eddy current and visual inspection have revealed vessels in generally good condition. Secondary side internals appear largely undergraded. Some tube to support fretting has been observed, and a number of tubes have been removed from service because of debris fretting concerns. To prepare for return to service, the primary side divider plates have been replaced and the tubes have been ID cleaned to restore the preheater to its original condition. This paper summarizes the inspection planning, findings, assessment for extended operation and maintenance activities undertaken. (author)

  3. A Model Independent Approach to (p)Reheating

    CERN Document Server

    Özsoy, Ogan; Sinha, Kuver; Watson, Scott

    2015-01-01

    In this note we propose a model independent framework for inflationary (p)reheating. Our approach is analogous to the Effective Field Theory of Inflation, however here the inflaton oscillations provide an additional source of (discrete) symmetry breaking. Using the Goldstone field that non-linearly realizes time diffeormorphism invariance we construct a model independent action for both the inflaton and reheating sectors. Utilizing the hierarchy of scales present during the reheating process we are able to recover known results in the literature in a simpler fashion, including the presence of oscillations in the primordial power spectrum. We also construct a class of models where the shift symmetry of the inflaton is preserved during reheating, which helps alleviate past criticisms of (p)reheating in models of Natural Inflation. Extensions of our framework suggest the possibility of analytically investigating non-linear effects (such as rescattering and back-reaction) during thermalization without resorting t...

  4. Theory and Numerics of Gravitational Waves from Preheating after Inflation

    CERN Document Server

    Dufaux, Jean Francois; Felder, Gary N; Kofman, Lev; Uzan, Jean-Philippe

    2007-01-01

    Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast our method with other numerical methods in the literature, and then we apply it to preheating after chaotic inflation. In this case, we are able to check analytically our numerical results, which differ significantly from previous works. We discuss how the gravity wave spectrum builds up with time and find that the amplitude an...

  5. Preheating and Affleck-Dine leptogenesis after thermal inflation

    CERN Document Server

    Felder, G N; Park, W I; Stewart, E D; Felder, Gary N.; Kim, Hyunbyuk; Park, Wan-Il; Stewart, Ewan D.

    2007-01-01

    Previously, we proposed a model of low energy Affleck-Dine leptogenesis in the context of thermal inflation. The lepton asymmetry is generated at the end of thermal inflation, which occurs at a relatively low energy scale with the Hubble parameter somewhere in the range $1 \\keV \\lesssim H \\lesssim 1 \\MeV$. Thus Hubble damping will be ineffective in bringing the Affleck-Dine field into the lepton conserving region near the origin, leaving the possibility that the lepton number could be washed out. Previously, we suggested that preheating could damp the amplitude of the Affleck-Dine field allowing conservation of the lepton number. In this paper, we demonstrate numerically that preheating does efficiently damp the amplitude of the Affleck-Dine field and that the lepton number is conserved as the result. In addition to demonstrating a crucial aspect of our model, it also opens the more general possibility of low energy Affleck-Dine baryogenesis.

  6. Risk Factors in Heating, Ventilating, and Air-Conditioning Systemsfor Occupant Symptoms in U.S. Office Buildings: the EPA BASE Study

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, M.J.; Lei-Gomez, Q.; Mirer, A.; Seppanen, O.; Brunner, G.

    2006-10-01

    Nonspecific building-related symptoms among occupants of modern office buildings worldwide are common and may be associated with important reductions in work performance, but their etiology remains uncertain. Characteristics of heating, ventilating, and air-conditioning (HVAC) systems in office buildings that increase risk of indoor contaminants or reduce effectiveness of ventilation may cause adverse exposures and subsequent increase in these symptoms among occupants. We analyzed data collected by the U.S. EPA from a representative sample of 100 large U.S. office buildings--the Building Assessment and Survey Evaluation (BASE) study--using multivariate logistic regression models with generalized estimating equations adjusted for potential personal and building confounders. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between seven building-related symptom outcomes and selected HVAC system characteristics. Among factors of HVAC design or configuration: Outdoor air intakes less than 60 m above the ground were associated with approximately doubled odds of most symptoms assessed. Sealed (non-operable) windows were associated with increases in skin and eye symptoms (ORs= 1.9, 1.3, respectively). Outdoor air intake without an intake fan was associated with an increase in eye symptoms (OR=1.7). Local cooling coils were associated with increased headache (OR=1.5). Among factors of HVAC condition, maintenance, or operation: the presence of humidification systems in good condition was associated with an increase in headache (OR=1.4), whereas the presence of humidification systems in poor condition was associated with increases in fatigue/difficulty concentrating, as well as upper respiratory symptoms (ORs=1.8, 1.5). No regularly scheduled inspections for HVAC components was associated with increased eye symptoms, cough and upper respiratory symptoms (ORs=2.2, 1.6, 1.5). Less frequent cleaning of cooling coils or drip pans was associated

  7. Displacement Ventilation

    DEFF Research Database (Denmark)

    Bjørn, Erik; Mattsson, Magnus; Sandberg, Mats

    Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment...

  8. Non-equilibrium Goldstone phenomenon in tachyonic preheating

    CERN Document Server

    Borsanyi, S; Sexty, D; Borsanyi, Sz.

    2003-01-01

    The dominance of the direct production of elementary Goldstone waves is demonstrated in tachyonic preheating by determining numerically the evolution of the dispersion relation, the equation of state and the kinetic power spectra for the angular degree of freedom of the complex matter field. The importance of the domain structure in the order parameter distribution for the quantitative understanding of the excitation mechanism is emphasized. Evidence is presented for the very early decoupling of the low-momentum Goldstone modes.

  9. 嘉兴市集中空调通风系统卫生监测结果分析%Analysis of the monitoring results for sanitary conditions of central air conditioning ventilation system in public places of Jiaxing

    Institute of Scientific and Technical Information of China (English)

    谢文芳; 周哲华; 富小飞; 吴水斌; 谢亮; 丁正贵

    2011-01-01

    Objective: To analyze the monitoring results of sanitary conditions of central air conditioning ventilation system in public places of Jiaxing, so as to prevent and control harmful factors that may appear to affect health. Methods; Randomly collected the blowing air (petri dish) , samples from the duct inner surface (smear), and samples of cooling water and condensed water of central air conditioning ventilation systems in different industries, and valuated them in compliance with Health Regulations for Central Air Conditioning Ventilation System in Public Places. Results: The pass rate of total bacteria and total epiphyte contained in the blowing air of central air conditioning ventilation system in Jiaxing were all below 70% during these two years, but the pass rate of β - hemolytic streptococcus was 100% , the differences among bacteria, epiphyte and β - hemolytic streptococcus have statistical significance (2009, χ2 = 20. 20 ,P < 0.001; 2010, χ2 = 6.24 ,P < 0.05). The difference of pass rate of total bacteria (χ2 = 21.36,P<0.001) and total epiphyte(χ2 = 38.49,P<0.001) , which contained in the blowing air of central air conditioning ventilation system in different industries, has statistical significance. The positive rate of Legionella pneumophila in cooling water, condensed water was 29.6%. Conclusion-. To standardize hygienic valuation for central air conditioning ventilation system in public places, and found a professional cleaning and disinfection team for central air conditioning ventilation system is the key for guaranteeing a good sanitary quality.%目的:分析嘉兴市集中空调通风系统卫生监测结果,以预防和控制可能出现的健康危害因素.方法:采集不同行业集中空调通风系统送风中空气(平皿)、风管内表面(涂抹样)及冷却水、冷凝水样,按公共场所集中空调通风系统卫生规范进行评价.结果:二年中嘉兴市集中空调通风系统送风中空气细菌总数、

  10. Validation of a Human Exhalation Flow Simulation in a Room with Vertical Ventilation

    DEFF Research Database (Denmark)

    Olmedo, Inés; Nielsen, Peter V.; Adana, M. Ruiz de

    2012-01-01

    We protect ourselves from airborne cross-infection in our indoor environment by supplying fresh air to the room by natural or mechanical ventilation. The air is distributed in the room according to different principles as e.g. mixing ventilation, downward ventilation, displacement ventilation, et...

  11. Gauge-preheating and the end of axion inflation

    CERN Document Server

    Adshead, Peter; Scully, Timothy R; Sfakianakis, Evangelos I

    2015-01-01

    We study the onset of the reheating epoch at the end of axion-driven inflation where the axion is coupled to an Abelian, $U(1)$, gauge field via a Chern-Simons interaction term. We focus primarily on $m^2\\phi^2$ inflation and explore the possibility that preheating can occur for a range of coupling values consistent with recent observations and bounds on the overproduction of primordial black holes. We find that for a wide range of parameters preheating is efficient. In certain cases the inflaton is seen to transfer all its energy to the gauge fields within a few oscillations. We find that the gauge fields on sub-horizon scales end in an unpolarized state, due to the existence of strong rescattering between the inflaton and gauge modes. We also present a preliminary study of an axion monodromy model coupled to $U(1)$ gauge fields, seeing a similarly efficient preheating behavior as well as indications that the coupling strength has an effect on the creation of oscillons.

  12. Gravitational Waves from Preheating in M-flation

    CERN Document Server

    Ashoorioon, Amjad; Mann, Robert B; Oltean, Marius; Sheikh-Jabbari, M M

    2014-01-01

    Matrix inflation, or M-flation, is a string theory motivated inflationary model with three scalar field matrices and gauge fields in the adjoint representation of the $\\mathbf{U}(N)$ gauge group. One of these $3N^2$ scalars appears as the effective inflaton while the rest of the fields (scalar and gauge fields) can play the role of isocurvature fields during inflation and preheat fields afterwards. There is a region in parameter space and initial field values, "the hilltop region," where predictions of the model are quite compatible with the recent \\textit{Planck} data. We show that in this hilltop region, if the inflaton ends up in the supersymmetric vacuum, the model can have an embedded preheating mechanism. % only if inflation happens around the supersymmetric vacuum. % Couplings of the preheat modes are related to the inflaton self-couplings and therefore are known from the CMB data. Through lattice simulations performed using a symplectic integrator, we numerically compute the power spectra of gravitati...

  13. The use of a double heat pipe heat exchanger system for reducing energy consumption of treating ventilation air in an operating theatre. A full year energy consumption model simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yau, Y.H. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2008-07-01

    In two earlier papers [Y.H. Yau, Application of a heat pipe heat exchanger to dehumidification enhancement in tropical HVAC systems - a baseline performance characteristics study, International Journal of Thermal Sciences 46 (2) (2007) 164-171; ], two series of experiments were conducted under controlled conditions to establish the baseline performance characteristics of the heat pipe heat exchanger (HPHX). In the present paper, a complete empirical transient systems simulation program model is assembled to estimate the air states as well as the entire typical meteorological year energy consumption of an operating theatre located in Kuala Lumpur, Malaysia. The current heating, ventilating and air conditioning (HVAC) systems for the operating theatre are found to be inherently energy-inefficient and can be further improved with a double heat pipe heat exchanger system. The impact on actual energy consumption of a custom-built Trane Air Handler Unit 0704 2-2MB is simulated with two 8-row heat pipe heat exchanger installed in the heating, ventilating and air conditioning system compared to the existing without HPHX HVAC system. Based on this investigation, the application of a double heat pipe heat exchanger system (Plant E) in the conventional Air Handler Unit operating in a tropical climate is strongly recommended as an efficient mean for humidity control and energy savings to maintain acceptable room conditions per American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) requirements [ASHRAE, ASHRAE Handbook HVAC Applications SI Edition, ASHRAE, Atlanta, GA, USA, 1995]. (author)

  14. Evaluation of a natural gas compressor building with switch-back air inlet entrances and ventilated by compressor package coolers

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Timothy G. [HFP Acoustical Consultants Inc. (United States)], email: tim.simmons@hfpacoustical.com

    2011-07-01

    The booming natural gas market in the Marcellus shale region has seen the appearance of many oil and gas processing stations, the latter generating a great deal of noise, which disturbs local residents. The oil and gas companies have therefore developed a patchwork of noise reduction techniques, from basic mufflers to engineered, sound-proof buildings. This paper focuses on a compromise: a gas compressor station, located in Lycoming County, Pennsylvania, encased in a light-weight, metal building with switch-back air inlet openings for cooling and noise reduction. This case study aims to measure the noise emissions of the compressor, and possibly propose solutions for its mitigation. Since Lycoming County has a fairly stringent policy on noise disturbance, especially for low-frequency sounds, noise emission results showed that switch-back openings and the walls of the compressor building must be mitigated and that action must be taken by the gas company to meet the noise ordinance requirements.

  15. On application of intelligent access control system in energy-saving of heating ventilation air-conditioner system%谈智能门禁系统在暖通空调系统节能中的应用

    Institute of Scientific and Technical Information of China (English)

    苏伟; 焦春玲; 罗炜

    2012-01-01

    The paper introduces the basic components and functions of the intelligent access control system,illustrates the application of the intelligent access control system in the various energy-saving of heating ventilation air-conditioner systems,including the workhouse heating system,the ventilation system,and the air-conditioner system,so as to direct the practice and to enhance the development of the energy-saving technique of the heating ventilation air-conditioner.%针对智能门禁系统的基本组成及功能进行了具体介绍,分别阐述了智能门禁系统在厂房采暖系统、通风系统、空调系统等不同的暖通空调系统节能中的应用,以期指导实践,促进暖通空调领域节能技术的发展。

  16. Cooling-energy Reduction of Air-conditioned Ofifces by Using Night Natural Ventilation%夜间自然通风降低办公室空调制冷能耗

    Institute of Scientific and Technical Information of China (English)

    尚城名; 张玉辉; 何江海

    2016-01-01

    Night natural ventilation has been successfully applied to many passively-cooled or low-energy office buildings. This paper investigates the applicability of night natural ventilation in office buildings. A thermal and ventilation simulation model, together with suitable weather data were used to examine the energy saving and internal comfort conditions. It was found that natural ventilation strategies could save cooling-energy in typical air-conditioned office. Based on the principle of “the best” application, such as improving air-tightness, and minimization of internal and solar heat gains to improve building structure can effectively improve the energy saving of natural ventilation.%夜间自然通风已经成功运用于许多被动制冷或低能耗写字楼中。介绍了夜间自然通风在写字楼中的适用性。在适当的温度条件下,建立热量计通风模型,以此来检验节能以及内部舒适度改善情况。研究发现,自然通风模式能够减少传统空调写字间的制冷能耗。采用“应用最佳”的原则,如提高气密性、内部发热及日晒生热的最小化等改善建筑结构能有效提高自然通风的节能性。

  17. Simulating People Moving in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Mattsson, M.; Bjørn, Erik; Sandberg, M.

    A displacement ventilation system works better the more uni-directional the air flow through the ventilated room is: from floor to ceiling. Thus, from an air quality point of view, there should be as little vertical mixing of the room air as possible. It is therefore comprehensible that physical...... activity in the room -like peoples movements -in previous studies has been shown to influence the effectiveness of the ventilation. In this study we have compared results from previous tests, where a cylindrical person simulator was used, to results obtained when using a person simulator of more human...

  18. Building cooling by night-time ventilation

    Institute of Scientific and Technical Information of China (English)

    卢军; 王曦; 甘灵丽

    2009-01-01

    Nowadays,the world is short of energy source,and larger proportion of building energy consumption is occupied by air conditioning system. It is urgent that not only importance should be attached on energy saving but also arcology energy technology based on green and sustainable thought should be advocated. Considering the ever growing energy consumption of residential buildings,intermittent ventilation is a solution to saving energy consumption and improving indoor thermal comfort. Aiming at reducing indoor air temperature by intermittent ventilation and decrease energy consumption of air conditioning system,with the help of DeST (Designer’s Simulation Toolkit) this paper analyzes the characteristics of air conditioning load and year round air conditioning time in Chongqing located in hot summer and cold winter zone,obtains the amount of energy consumption saved at different ventilation rates,and recommends suitable ventilation rate in hot summer and cold winter zone.

  19. Infiltration as Ventilation: Weather-Induced Dilution

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, William J.N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-06-01

    The purpose of outdoor air ventilation is to dilute or remove indoor contaminants to which occupants are exposed. It can be provided by mechanical or natural means. In most homes, especially older homes, weather-driven infiltration provides the dominant fraction of the total ventilation. As we seek to provide good indoor air quality at minimum energy cost, it is important to neither over-ventilate nor under-ventilate. Thus, it becomes critically important to evaluate correctly the contribution infiltration makes to the total outdoor air ventilation rate. Because weather-driven infiltration is dependent on building air leakage and weather-induced pressure differences, a given amount of air leakage will provide different amounts of infiltration. Varying rates of infiltration will provide different levels of contaminant dilution and hence effective ventilation. This paper derives these interactions and then calculates the impact of weather-driven infiltration for different climates. A new “N-factor” is introduced to provide a convenient method for calculating the ventilation contribution of infiltration for over 1,000 locations across North America. The results of this work could be used in indoor air quality standards (specifically ASHRAE 62.2) to account for the contribution of weather-driven infiltration towards the dilution of indoor pollutants.

  20. Evaporation Controlled Emission in Ventilated Rooms

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Heiselberg, Per

    -scale ventilated room when the emission is fully or partly evaporation controlled. The objective of the present research work has been to investigate the change of emission rates from small-scale experiments to full-scale ventilated rooms and to investigate the influence of the local air velocity field near...