WorldWideScience

Sample records for solar preheated ventilation

  1. Solar Preheated Ventilation - Innovative Solar Technology

    National Research Council Canada - National Science Library

    Gaberson, Howard

    1999-01-01

    .... This innovative technology applies to both new construction or rehabilitation projects. This TDS introduces this low maintenance solar technology for consideration in all future industrial ventilation or HVAC projects...

  2. Instrumentation strategies for energy conservation in broiler barns with ventilation air solar pre-heaters

    Energy Technology Data Exchange (ETDEWEB)

    Cordeau, Sebastien; Barrington, Suzelle [Department of Bioresource Engineering, Macdonald Campus of McGill University, 21 111 Lakeshore, Ste Anne de Bellevue, Quebec H9X 3V9 (Canada)

    2010-08-15

    At the present consumption rate, world fossil-fuel reserves are expected to be depleted by 2050 unless their consumption is optimized and supplemented with renewable energy sources. The objective of this project was to evaluate the performance of a simple data acquisition system installed to conduct an energy balance and identify energy saving strategies in two commercial broilers barns with ventilation air solar pre-heaters. Located near Montreal, Canada, the two identical barns were instrumented for inside and outside air conditions, ventilation rate and energy recovery by the solar air pre-heaters. Whereas the temperature, relative humidity and radiation sensors were reliable, inside air temperature stratification complicated energy balance analyses and broiler heat production rate calculations. Lack of room air mixing resulted in the loss of 25 and 15% of the generated heater load and recovered solar energy. The proper monitoring of all environmental conditions required their measurement every 5 rather than 20 min. Instead of using a data transmission service found to be unreliable in rural areas, all data loggers were downloaded onto a portable computer every 45 days during regular instrument maintenance. Accordingly, room air mixing is recommended to facilitate energy balance studies and improve the efficient use of heating energies. (author)

  3. Preheating of tap water with solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Granum, H; Raaen, H

    1992-05-05

    In 1991 SINTEF Architecture and Building Technology won the second prize in 'The Nordic Competition for Low Energy Buildings' with a project proposal named 'LOWe'. The paper gives a description of the energy-saving features of this project, particularly the use of a solar collector for preheating of tap water. Compared with the economic profitability of other saving efforts in the project, such as good thermal insulation and efficient heat recovering system, the system for solar preheating of tap water does not seem very attractive for the time being. Loose estimates indicate a cost of close of NOK 1.00 per kWh for the produced energy in the solar collector, while the present price for electricity in Norway is about NOK 0.50 per kWh. Compared with a heat pump solution however the energy cost is not unreasonable.

  4. 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.

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

    OpenAIRE

    Zheng, Bin; Liu, Yongqi; Liu, Ruixiang; Meng, Jian; Mao, Mingming

    2015-01-01

    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 res...

  6. Solar pre-heating of water for steam generation in the friendship textile mill

    International Nuclear Information System (INIS)

    Sid -Ahmed, M.O.; Hussien, T.

    1994-01-01

    The technology of solar water heating is simple and can be used for pre-heating of water entering a boiler. In this paper the economics of solar pre-heating of water was calculated. The calculations were based on the performance and cost of a locally-made flat plate collector, and the performance and fuel consumption of a boiler in a textile mill. The results showed that a collector area of about 800 meter square with initial cost of about LS 5,000,000, could save annually about 130 tons of furnace oil. ( Author )

  7. Flat plate solar collector for water pre-heating using concentrated solar power (CSP)

    Science.gov (United States)

    Peris, Leonard Sunny; Shekh, Md. Al Amin; Sarker, Imran

    2017-12-01

    Numerous attempt and experimental conduction on different methods to harness energy from renewable sources are being conducted. This study is a contribution to the purpose of harnessing solar energy as a renewable source by using flat plate solar collector medium to preheat water. Basic theory of solar radiation and heat convection in water (working fluid) has been combined with heat conduction process by using copper tubes and aluminum absorber plate in a closed conduit, covered with a glazed through glass medium. By this experimental conduction, a temperature elevation of 35°C in 10 minutes duration which is of 61.58% efficiency range (maximum) has been achieved. The obtained data and experimental findings are validated with the theoretical formulation and an experimental demonstration model. A cost effective and simple form of heat energy extraction method for space heating/power generation has been thoroughly discussed with possible industrial implementation possibilities. Under-developed and developing countries can take this work as an illustration for renewable energy utilization for sustainable energy prospect. Also a full structure based data to derive concentrated solar energy in any geographical location of Bangladesh has been outlined in this study. These research findings can contribute to a large extent for setting up any solar based power plant in Bangladesh irrespective of its installation type.

  8. Preheating Water In The Covers Of Solar Water Heaters

    Science.gov (United States)

    Bhandari, Pradeep

    1995-01-01

    Solar water heaters that include glass covers over absorber plates redesigned to increase efficiencies according to proposal. Redesign includes modification of single-layer glass cover into double-layer glass cover and addition of plumbing so cool water to be heated made to flow between layers of cover before entering absorber plate.

  9. Diagnostics of electron-heated solar flare models. III - Effects of tapered loop geometry and preheating

    Science.gov (United States)

    Emslie, A. G.; Li, Peng; Mariska, John T.

    1992-01-01

    A series of hydrodynamic numerical simulations of nonthermal electron-heated solar flare atmospheres and their corresponding soft X-ray Ca XIX emission-line profiles, under the conditions of tapered flare loop geometry and/or a preheated atmosphere, is presented. The degree of tapering is parameterized by the magnetic mirror ratio, while the preheated atmosphere is parameterized by the initial upper chromospheric pressure. In a tapered flare loop, it is found that the upward motion of evaporated material is faster compared with the case where the flare loop is uniform. This is due to the diverging nozzle seen by the upflowing material. In the case where the flare atmosphere is preheated and the flare geometry is uniform, the response of the atmosphere to the electron collisional heating is slow. The upward velocity of the hydrodynamic gas is reduced due not only to the large coronal column depth, but also to the increased inertia of the overlying material. It is concluded that the only possible electron-heated scenario in which the predicted Ca XIX line profiles agree with the BCS observations is when the impulsive flare starts in a preheated dense corona.

  10. Simple air collectors for preheating fresh air

    NARCIS (Netherlands)

    Hensen, J.L.M.; Wit, de M.H.; Ouden, den C.

    1984-01-01

    In dwellings with mechanical ventilation systems the fresh air can easily be preheated by means of simple solar air systems. These can be an integral part of the building facade or roof and the costs are expected to be low. By means of computer experiments a large number of systems were evaluated.

  11. Potential of roof-integrated solar collectors for preheating air at drying facilities in Northern Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Franz; Nagle, Marcus; Leis, Hermann; Mueller, Joachim [Institute of Agricultural Engineering 440e, University of Hohenheim, Garbenstrasse 9, 70599 Stuttgart (Germany); Janjai, Serm [Department of Physics, Silpakorn University, Nakhon Pathom (Thailand); Mahayothee, Busarakorn [Department of Food Technology, Silpakorn University, Nakhon Pathom (Thailand); Haewsungcharoen, Methinee [Department of Food Engineering, Chiang Mai University, Chiang Mai (Thailand)

    2009-07-15

    Longan is one of the most widely cropped fruits in Northern Thailand, where a significant amount of the annual harvest is commercially dried and exported as a commodity. Liquefied petroleum gas is generally used as the energy source for heating the drying air, but concern is growing as fuel prices are expected to increase for the foreseeable future. Meanwhile, with the ample solar radiation in Thailand, the roofs of drying facilities could be adapted to serve as solar collectors to preheat the drying air, thus reducing the energy requirement from fossil fuels. In this study, a simulation program for a flat-plate solar air heater was used to estimate the potential to preheat drying air given the conditions of several longan drying facilities. Results showed that solar collectors can replace up to 19.6% of the thermal energy demand during the drying season. Bigger collectors and smaller air channels result in more useful heat, but attention has to be paid to costs and pressure drop, respectively. Annual monetary savings can reach up to THB 56,000 ({approx}US$ 1800 at US$ 1 THB 31). (author)

  12. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Science.gov (United States)

    Jones, C. B.; Smetana, F. O.

    1977-01-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using isolation levels present in North Carolina are presented. The effects of monthly variations in isolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  13. Solar chimney for natural ventilation: A review

    Science.gov (United States)

    Dhrubo, Abir Ahsan; Alam, Chowdhury Sadid; Rahman, Md. Mustafizur; Islam, A. K. M. Sadrul

    2017-06-01

    In the 21st century the talk of the time has been proper use of renewable energy sources due to the continuous depletion of non-renewable energy sources and global warming as a result of combustion of fossil fuels. The energy situation in the 3rd world countries is even worse. The continuous industrial development in the 1st world countries is hugely responsible for global temperature increase and greenhouse gas (GHG) emissions which badly affect the countries like Bangladesh. As of April 2016, the electricity generation capacity of Bangladesh was 12,399 MW to which only 60% of the total population have access to. The shortage of electricity during the summer season makes life very difficult. Cooling of buildings requires a large quantity of energy in the summer. An alternative cooling system can reduce the dependency on electricity. This paper specially deals with a passive cooling system that reduces pressure on the electricity supply and focuses on renewable energy sources. Here a different process engineering has been discussed which incorporates Earth-to-Air Heat Exchangers with solar collector enhanced solar chimney system. In this study natural ventilation of buildings, using solar chimney system is reviewed extensively. Experimentally it has already been observed that sufficient temperature drop takes place 2-3 m within the undisturbed ground, which can work as a heat sink for ambient air if passed through and can lead to attaining comfort zone at a confined location. During peak hours of summer this kind of system may work as a very efficient cooling system and reduces extra load on electricity supply.

  14. Feasibility of utilising solar-induced ventilation in Malaysia

    International Nuclear Information System (INIS)

    Ong, K.S.; Chow, C.C.

    2006-01-01

    The feasibility of applying solar-induced ventilation in a typical Malaysian house measuring 3 m high x wide x 5 m deep was considered based on experimental results obtained from a laboratory-scale model. A wall-type solar chimney was considered. The design of the solar chimney incorporated providing a glass panel alongside a vertical wall of a building. Openings at the top and bottom of the wall allowed fresh air to be introduced into the building. Simulations obtained from a simple theoretical model showed that the solar chimney was able to induce air flow rates of between 640 to 1040 m3 h-1 with a 0.3 m air gap. These ventilation rates are found to be in compliance with codes specified by ASHRAE and the Uniform Building By-laws. Full scale studies would need to be conducted in order to evaluate its effectiveness especially the flow pattern in the room

  15. Adaptive heating, ventilation and solar shading for dwellings

    NARCIS (Netherlands)

    Alders, E.E.

    2017-01-01

    Calculation of various strategies for the heating of, and the prevention of overheating in, a Dutch standard dwelling that includes (automated) adaptive ventilation systems and solar shading to maintain indoor temperatures at acceptably comfortable temperatures informs this analysis of the costs,

  16. 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.

  17. Low cost bare-plate solar air collector

    Science.gov (United States)

    Maag, W. L.; Wenzler, C. J.; Rom, F. E.; Vanarsdale, D. R.

    1980-09-01

    A low cost, bare plate solar collector for preheating ambient air was developed. This type of solar heating system would be applicable for preheating ventilation air for public buildings or other commercial and industrial ventilation requirements. 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 percent or greater with air preheat temperature uses up to 20 degrees for one of the prototypes. The economic analyses indicated that this type of solar system was economically viable. For the materials of construction and the type of fabrication and installation perceived, costs for the bare plate solar collector are attainable. Applications for preheating ventilation air for schools were evaluated and judged to be economically viable.

  18. Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Svendsen, Sv Aa Højgaard

    1999-01-01

    The note concerns ventilation in residential buildings. Describes components in ventilation systems, electric energy consumption and different ventilation systems with heat exchanger.......The note concerns ventilation in residential buildings. Describes components in ventilation systems, electric energy consumption and different ventilation systems with heat exchanger....

  19. Solar Walls in tsbi3

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne

    tsbi3 is a user-friendly and flexible computer program, which provides support to the design team in the analysis of the indoor climate and the energy performance of buildings. The solar wall module gives tsbi3 the capability of simulating solar walls and their interaction with the building....... This version, C, of tsbi3 is capable of simulating five types of solar walls say: mass-walls, Trombe-walls, double Trombe-walls, internally ventilated walls and solar walls for preheating ventilation air. The user's guide gives a description of the capabilities and how to simulate solar walls in tsbi3....

  20. Solar-powered ventilation of African termite mounds.

    Science.gov (United States)

    Ocko, Samuel A; King, Hunter; Andreen, David; Bardunias, Paul; Turner, J Scott; Soar, Rupert; Mahadevan, L

    2017-09-15

    How termite mounds function to facilitate climate control is still only partially understood. Recent experimental evidence in the mounds of a single species, the south Asian termite Odontotermes obesus , suggests that the daily oscillations of radiant heating associated with diurnal insolation patterns drive convective flow within them. How general this mechanism is remains unknown. To probe this, we consider the mounds of the African termite Macrotermes michaelseni , which thrives in a very different environment. By directly measuring air velocities and temperatures within the mound, we see that the overall mechanisms and patterns involved are similar to that in the south Asian species. However, there are also some notable differences between the physiology of these mounds associated with the temporal variations in radiant heating patterns and CO 2 dynamics. Because of the difference between direct radiant heating driven by the position of the sun in African conditions, and the more shaded south Asian environments, we see changes in the convective flows in the two types of mounds. Furthermore, we also see that the south Asian mounds show a significant overturning of stratified gases, once a day, while the African mounds have a relatively uniform concentration of CO 2 Overall, our observations show that despite these differences, termite architectures can harness periodic solar heating to drive ventilation inside them in very different environments, functioning as an external lung, with clear implications for human engineering. © 2017. Published by The Company of Biologists Ltd.

  1. A First Approach to Natural Thermoventilation of Residential Buildings through Ventilation Chimneys Supplied by Solar Ponds

    Directory of Open Access Journals (Sweden)

    Ferdinando Salata

    2015-07-01

    Full Text Available The exploitation of natural ventilation is a good solution to improve buildings from an energetic point of view and to fulfill the requirements demanded by the thermohygrometric comfort and the air quality in enclosed spaces. Some past researches demonstrated how some devices, useful to this purpose, follow the principles of solar chimneys and are able to move air masses while exploiting the Archimedes thrust. The natural ventilation must be supplied by a flow moving upward, generated by a heat source performing at temperatures slightly higher than the one present in the environment. To have a minimum energetic effect, the heat can be extracted from solar ponds; solar ponds are able to collect and store solar energy in the geographical regions characterized by sufficient values of solar radiation. Thus it is possible, in summer, to provoke a nocturnal natural ventilation useful for the air change in indoor spaces (in those climatic areas where, during the night, there is a temperature gradient.

  2. Solar chimney: A sustainable approach for ventilation and building space conditioning

    Directory of Open Access Journals (Sweden)

    Lal, S.,

    2013-03-01

    Full Text Available The residential and commercial buildings demand increase with rapidly growing population. It leads to the vertical growth of the buildings and needs proper ventilation and day-lighting. The natural air ventilation system is not significantly works in conventional structure, so fans and air conditioners are mandatory to meet the proper ventilation and space conditioning. Globally building sector consumed largest energy and utmost consumed in heating, ventilation and space conditioning. This load can be reduced by application of solar chimney and integrated approaches in buildings for heating, ventilation and space conditioning. It is a sustainable approach for these applications in buildings. The authors are reviewed the concept, various method of evaluation, modelings and performance of solar chimney variables, applications and integrated approaches.

  3. Comparison of the Energy Conversion Efficiency of a Solar Chimney and a Solar PV-Powered Fan for Ventilation Applications

    Directory of Open Access Journals (Sweden)

    Lubomír Klimeš

    2018-04-01

    Full Text Available A study into the performance of a solar chimney and a solar photovoltaic (PV-powered fan for ventilation applications was carried out using numerical simulations. The performance of the solar chimney was compared with that of a direct current (DC fan powered by a solar PV panel. The comparison was carried out using the same area of the irradiated surface—the area of the solar absorber plate in the case of the solar chimney and the area of the solar panel in the case of the photovoltaic-powered fan. The two studied cases were compared under various solar radiation intensities of incident solar radiation. The results indicate that the PV-powered fans significantly outperform solar chimneys in terms of converting solar energy into the kinetic energy of air motion. Moreover, ventilation with PV-powered fans offers more flexibility in the arrangement of the ventilation system and also better control of the air flow rates in the case of battery storage.

  4. OUT Success Stories: Transpired Solar Collectors

    International Nuclear Information System (INIS)

    Clyne, R.

    2000-01-01

    Transpired solar collectors are a reliable, low-cost technology for preheating building ventilation air. With simple payback periods ranging from 3 to 12 years and an estimated 30-year life span, transpired collector systems offer building owners substantial cost savings

  5. Gravity mediated preheating

    International Nuclear Information System (INIS)

    Maity, Debaprasad

    2015-01-01

    In this work we propose a mechanism of natural preheating of our universe induced by the inflation field dependent effective mass term for the gravitational wave. For any single field inflationary model, the inflation must go through the oscillatory phase after the end of inflation. As has recently been shown, if the gravitational fluctuation has inflation dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflation though parametric resonance. Because of this large enhancement of the amplitude of the gravitational wave, we show that universe can be naturally pre-heated through a minimally coupled matter field with gravity. Therefore, during the pre-heating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflation. (author)

  6. Solar Heat Gain Reduction of Ventilated Double Skin Windows without a Shading Device

    Directory of Open Access Journals (Sweden)

    Bokyoung Koo

    2017-12-01

    Full Text Available With global efforts to strengthen various energy-saving policies for buildings to reduce greenhouse gas emissions, in South Korea, new laws and regulations have been in force since May 2015 to install shading devices in public buildings and to include the solar heat gain coefficient (SHGC reduction performance of shading devices in the evaluation of building performance. By making a ventilated air layer outer glass and inner glass to lower the temperatures of the air layer and glass surface, it is possible to reduce the amount of heat flowing into the building while maintaining the same level of light transmission as plain window systems. This study proposes a double-skin façade window with a 20 mm ventilated air cavity, and assumes that insolation inflow indoors would be reduced through ventilation in the air cavity. The artificial solar lab test results show that the SHGC can be lowered through ventilation by 28% to 52.9%. Additionally, in an outdoor test cell experiment, the results show that the mean temperature was 0.6 K and the peak temperature was 0.9 K lower with ventilation in the air cavity than that without ventilation in the air cavity.

  7. Application of Breathing Architectural Members to the Natural Ventilation of a Passive Solar House

    Directory of Open Access Journals (Sweden)

    Kyung-Soon Park

    2016-03-01

    Full Text Available The efficient operation of a passive solar house requires an efficient ventilation system to prevent the loss of energy and provide the required ventilation rates. This paper proposes the use of “breathing architectural members” (BAMs as passive natural ventilation devices to achieve much improved ventilation and insulation performance compared to mechanical ventilation. Considering the importance of evaluating the ventilation and insulation performances of the members, we also propose numerical models for predicting the heat and air movements afforded by the members. The numerical model was validated by comparison with experimental results. The effectiveness of the BAMs was also verified by installation in houses located in an area with warm climate. For this purpose, chamber experiments were performed using samples of the BAMs, as well as numerical simulations to assess natural ventilation and heat load. The main findings of the study are as follows: (1 the one-dimensional chamber experiments confirmed the validity of the numerical models for predicting the heat and air movements afforded by the BAMs. Comparison of the experimental and calculated values for the temperature of air that flowed into the room from outside revealed a difference of less than 5%; (2 observations of the case studies in which BAMs were installed in the ceilings and exterior walls of Tokyo model houses revealed good annual ventilation and energy-saving effects. When BAMs with an opening area per unit area of A = 0.002 m2/m2 were applied to three surfaces, the required ventilation rate was 0.5 ACH (air changes per hour, and this was achieved consistently. Compared to a house with general insulation and conventional mechanical ventilation, heating load was reduced by 15.3%–40.2% depending on the BAM installation points and the differing areas of the house models.

  8. Experimental and Numerical Studies of Solar Chimney for Ventilation in Low Energy Buildings

    DEFF Research Database (Denmark)

    Zha, Xinyu; Zhang, Jun; Qin, Menghao

    2017-01-01

    As an effective way to protect environment and save energy in buildings, passive ventilation method has generated intense interest for improving indoor thermal environment in recent years. Among these passive ventilation solutions, design of solar chimney in buildings is a promising approach...... the performance of a full-scale solar chimney in a real building in East-ern China. The measured performance is compared with theoretical calculation and numerical simulation. In a solar chimney of 6.2m length, 2.8m width and 0.35m air gap, the experimental results show that air flow rate of 70.6 m3/h~1887.6 m3/h...... can be achieved during the daytime in the testing day. Comparing measured value with theoretical value, the flow rate is generally lower than the theoretical value. By data analysis, the suggested discharge coefficient Cd of solar energy in real engineering project is 0.51. With the use...

  9. Inflation After Preheating

    CERN Document Server

    Felder, G; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Kofman, Lev; Linde, Andrei; Tkachev, Igor

    2000-01-01

    Preheating after inflation may lead to nonthermal phase transitions with symmetry restoration. These phase transitions may occur even if the total energy density of fluctuations produced during reheating is relatively small as compared with the vacuum energy in the state with restored symmetry. As a result, in some inflationary models one encounters a secondary, nonthermal stage of inflation due to symmetry restoration after preheating. We review the theory of nonthermal phase transitions and make a prediction about the expansion factor during the secondary inflationary stage. We then present the results of lattice simulations which verify these predictions, and discuss possible implications of our results for the theory of formation of topological defects during nonthermal phase transitions.

  10. Nuclear fuel preheating system

    International Nuclear Information System (INIS)

    Andrea, C.

    1975-01-01

    A nuclear reactor new fuel handling system which conveys new fuel from a fuel preparation room into the reactor containment boundary is described. The handling system is provided with a fuel preheating station which is adaptd to heat the new fuel to reactor refueling temperatures in such a way that the fuel is heated from the top down so that fuel element cladding failure due to thermal expansions is avoided. (U.S.)

  11. Preheating in new inflation

    International Nuclear Information System (INIS)

    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 investigate 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 stage of decay of the inflaton field into other particles, which can be described by the perturbative approach to reheating after inflation. The resulting reheating temperature typically is rather low

  12. Optimization of a solar chimney design to enhance natural ventilation in a multi-storey office building

    NARCIS (Netherlands)

    Gontikaki, M.; Trcka, M.; Hensen, J.L.M.; Hoes, P.

    2010-01-01

    Natural ventilation of buildings can be achieved with solar-driven, buoyancy-induced airflow through a solar chimney channel. Research on solar chimneys has covered a wide range of topics, yet study of the integration in multi-storey buildings has been performed in few numerical studies, where

  13. Solar Sustainable Heating, Cooling and Ventilation of a Net Zero Energy House

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Skrupskelis, Martynas; Olesen, Bjarne W.

    Present work addresses the heating, cooling and ventilation concerns of the Technical University of Denmark’s house, Fold, for Solar Decathlon Europe 2012. Various innovative approaches are investigated, namely, utilization of ground, photo-voltaic/thermal (PV/T) panels and phase change materials...... (PCM). The ground heat exchanger acts as the heat sink and heat source for cooling and heating seasons, respectively. Free cooling enables the same cooling effect to be delivered with 8% of the energy consumption of a representative chiller. The heating and cooling needs of the house are addressed...... by the embedded pipes which are coupled with the ground. Ventilation is mainly used to control the humidity and to remove sensory and chemical pollution. PV/T panels enable the house to be a “plus” energy house. PV/T also yields to a solar fraction of 63% and 31% for Madrid and Copenhagen, respectively...

  14. Intelligent solar-powered automobile-ventilation system

    International Nuclear Information System (INIS)

    Huang, K. David; Tzeng, S.-C.; Ma Weiping; Wu Mingfung

    2005-01-01

    This study adopts airflow management technology to improve the local temperature distributions in an automobile to counteract the greenhouse effect. The automobile's temperature can be reduced to almost the outside temperature before the driver or passenger gets into the vehicle. When the engine is idling, the greenhouse-control system can be activated to remove the hot air from the car. An appropriate negative pressure is maintained to prevent stuffiness and save energy. The greenhouse-control system requires electrical power when the engine is idle, and a battery cannot supply sufficient power. An auxiliary solar-power supply can save energy and reduce the greenhouse effect of sunlight, while creating a comfortable traveling environment. It ensures that the engine is not overburdened and increases its service life, conserving energy, protecting the environment and improving comfort

  15. Preheating with extra dimensions

    International Nuclear Information System (INIS)

    Tsujikawa, S.

    2000-01-01

    We investigate preheating in a higher-dimensional generalized Kaluza-Klein theory with a quadratic inflaton potential V(/φ) = /frac12 m 2 /φ 2 including metric perturbations explicitly. The system we consider is the multi-field model where there exists a dilaton field /σ which corresponds to the scale of compactifications and another scalar field /χ coupled to inflaton with the interaction frac12 g 2 /φ 2 /χ 2 +/g-tilde 2 /φ 3 /χ. In the case of g-tilde=0, we find that the perturbation of dilaton does not undergo parametric amplification while the χ field fluctuation can be enhanced in the usual manner by parametric resonance. In the presence of the /g-tilde 2 /φ 3 /χ coupling, the dilaton fluctuation in sub-Hubble scales is modestly amplified by the growth of metric perturbations for the large coupling g-tilde. In super-Hubble scales, the enhancement of the dilaton fluctuation as well as metric perturbations is weak, taking into account the backreaction effect of created /χ particles. We argue that not only is it possible to predict the ordinary inflationary spectrum in large scales but extra dimensions can be held static during preheating in our scenario. (author)

  16. Augmenting natural ventilation using solar heat and free cool energy for residential buildings

    Directory of Open Access Journals (Sweden)

    N. B. Geetha

    2014-03-01

    Full Text Available In many urban buildings ventilation is not sufficient that will increase the temperature and also create unhealthy atmosphere inside the room. In such buildings artificially induced ventilation through freely available energy promote comfort conditions by reducing the temperature by 2 to 3°C and also creating good circulation of fresh air inside the room. In the present work the concept of improving the ventilation by excess hot energy available during summer days from the solar flat plate collector and by storing cool energy available during the early morning hour in the Phase Change Material (PCM based storage system is attempted. An experimental setup is made to study the effect of improvement in natural ventilation and the results are reported. A visible reduction in temperature is observed through circulation of air from the bottom side of the room to the roof of the house using the stored hot and cool energy. A CFD analysis is also carried out using ANSYS-CFX software to simulate and evaluate the mass flow of air at the inlet and at the selected RTD location by matching the transient temperature profile of the simulated result with the experimental results at the selected RTD location.

  17. 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...... affect measurements of air temperature and may lead to errors of high magnitude using bare thermocouples and even adopting shielding devices. Two different research groups, from Aalborg University and Politecnico di Torino, tested separately various techniques to shield thermocouples from direct...

  18. Effect of solar chimney inclination angle on space flow pattern and ventilation rate

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouny, Ramadan; Korah, Nader S.A. [Department of Mechanical Power Engineering and Energy, Minia University, Minia 61111 (Egypt)

    2009-02-15

    The solar chimney is a simple and practical idea that is applied to enhance space natural ventilation. The chimney could be vertical or inclined. The chimney inclination angle is an important parameter that greatly affects space flow pattern and ventilation rate. In the present study, the effect of chimney inclination angle on air change per hour and indoor flow pattern was numerically and analytically investigated. A numerical simulation using Ansys, a FEM-based code, was used to predict flow pattern. Then the results were compared with published experimental measurements. A FORTRAN program was developed to iteratively solve the mathematical model that was obtained through an overall energy balance on the solar chimney. The analytical results showed that an optimum air flow rate value was achieved when the chimney inclination is between 45 and 70 for latitude of 28.4 . The numerically predicted flow pattern inside the space supports this finding. Moreover, in the present study a correlation to predict the air change per hour was developed. The correlation was tested within a solar intensity greater than or equal to 500 W/m{sup 2}, and chimney width from 0.1 m to 0.35 m for different inclination angles with acceptable values. (author)

  19. 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.

  20. Preheating curvaton perturbations

    International Nuclear Information System (INIS)

    Bastero-Gil, M.; Di Clemente, V.; King, S.F.

    2005-01-01

    We discuss the potentially important role played by preheating in certain variants of the curvaton mechanism in which isocurvature perturbations of a D-flat (and F-flat) direction become converted to curvature perturbations during reheating. We discover that parametric resonance of the isocurvature components amplifies the superhorizon fluctuations by a significant amount. As an example of these effects we develop a particle physics motivated model which involves hybrid inflation with the waterfall field N being responsible for generating the μ term, the right-handed neutrino mass scale, and the Peccei-Quinn symmetry breaking scale. The role of the curvaton field can be played either by usual Higgs field, or the lightest right-handed sneutrino. Our new results show that it is possible to achieve the correct curvature perturbations for initial values of the curvaton fields of order the weak scale. In this model we show that the prediction for the spectral index of the final curvature perturbation only depends on the mass of the curvaton during inflation, where consistency with current observational data requires the ratio of this mass to the Hubble constant to be 0.3

  1. Enhancement of stack ventilation in hot and humid climate using a combination of roof solar collector and vertical stack

    Energy Technology Data Exchange (ETDEWEB)

    Yusoff, Wardah Fatimah Mohammad; Salleh, Elias [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Adam, Nor Mariah [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapian, Abdul Razak [Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Yusof Sulaiman, Mohamad [Solar Energy Research Institute, 3rd Floor, Tun Sri Lanang Library Building, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2010-10-15

    In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (T{sub i}-T{sub o}) is achieved in the semi-clear sky condition, which is about 9.9 C (45.8 C-35.9 C). Meanwhile, in the overcast sky condition, the highest air temperature difference (T{sub i}-T{sub o}) is 6.2 C (39.3 C-33.1 C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector's channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. (author)

  2. Techno-economic evaluation of a ventilation system assisted with exhaust air heat recovery, electrical heater and solar energy

    OpenAIRE

    Özyoğurtçu, Gamze; Mobedi, Moghtada; Özerdem, Barış

    2014-01-01

    The energy consumed to condition fresh air is considerable, particularly for the buildings such as cinema, theatre or gymnasium saloons. The aim of the present study is to design a ventilation system assisted with exhaust air heat recovery unit, electrical heater and stored solar energy, then to make an economical analysis based on life cycle cost (LCC) to find out its payback period. The system is able to recover thermal energy of exhaust air, store solar energy during the sunlight period an...

  3. Positioning Your Library for Solar (and Financial) Gain. Improving Energy Efficiency, Lighting, and Ventilation with Primarily Passive Techniques

    Science.gov (United States)

    Shane, Jackie

    2012-01-01

    This article stresses the importance of building design above technology as a relatively inexpensive way to reduce energy costs for a library. Emphasis is placed on passive solar design for heat and daylighting, but also examines passive ventilation and cooling, green roofs, and building materials. Passive design is weighed against technologies…

  4. An analytical and numerical study of solar chimney use for room natural ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouny, Ramadan; Koura, Nader S.A. [Department of Mechanical Power Engineering and Energy, Minia University, Minia 61111 (Egypt)

    2008-07-01

    The solar chimney concept used for improving room natural ventilation was analytically and numerically studied. The study considered some geometrical parameters such as chimney inlet size and width, which are believed to have a significant effect on space ventilation. The numerical analysis was intended to predict the flow pattern in the room as well as in the chimney. This would help optimizing design parameters. The results were compared with available published experimental and theoretical data. There was an acceptable trend match between the present analytical results and the published data for the room air change per hour, ACH. Further, it was noticed that the chimney width has a more significant effect on ACH compared to the chimney inlet size. The results showed that the absorber average temperature could be correlated to the intensity as: (T{sub w} = 3.51I{sup 0.461}) with an accepted range of approximation error. In addition the average air exit velocity was found to vary with the intensity as ({nu}{sub ex} = 0.013I{sup 0.4}). (author)

  5. 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.

  6. Gravitational-wave mediated preheating

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Stephon [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Marcianò, Antonino [Center for Field Theory and Particle Physics & Department of Physics, Fudan University, 200433 Shanghai (China); Yunes, Nicolás [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States)

    2015-04-09

    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.

  7. 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 ...

  8. Development and evaluation of a ceiling ventilation system enhanced by solar photovoltaic thermal collectors and phase change materials

    International Nuclear Information System (INIS)

    Lin, Wenye; Ma, Zhenjun; Sohel, M. Imroz; Cooper, Paul

    2014-01-01

    Highlights: • A novel ceiling ventilation system enhanced by PVT and PCMs was proposed. • PCM was used to increase the local thermal mass and to serve as a storage unit. • The proposed system can enhance indoor thermal comfort in winter and summer. - Abstract: This paper presents the development and performance evaluation of a novel ceiling ventilation system integrated with solar photovoltaic thermal (PVT) collectors and phase change materials (PCMs). The PVT collectors are used to generate electricity and provide low grade heating and cooling energy for buildings by using winter daytime solar radiation and summer night-time sky radiative cooling, respectively. The PCM is integrated into the building ceiling as a part of the ceiling insulation and at the same time, as a centralized thermal energy storage to temporally store low grade energy collected from the PVT collectors. The performance of the proposed system was numerically evaluated based on a Solar Decathlon house using TRNSYS. The results showed that, in winter conditions, the proposed PVT–PCM integrated ventilation system can significantly improve the indoor thermal comfort of passive buildings without using air-conditioning systems with a maximum air temperature rise of 23.1 °C from the PVT collectors. Compared with the system using PCM but without using PVT collectors, the coefficient of thermal comfort enhancement in the kitchen, dining room and living room of the case building studied using the proposed system improved from almost zero to 0.9823 while the coefficient of thermal comfort enhancement in the study room improved from 0.0060 to 0.9921. In summer conditions, the proposed system can also enhance indoor thermal comfort through night-time sky radiative cooling

  9. Hybrid preheat/recirculating steam generator

    International Nuclear Information System (INIS)

    Lilly, G.P.

    1985-01-01

    The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

  10. Preheat operating experiences at the FFTF

    International Nuclear Information System (INIS)

    Tucker, W.R.

    1978-01-01

    The rather extensive test program performed on the FFTF preheat control system resulted in successful sodium fill of one secondary heat transport loop on July 2, 1978. The data obtained during testing and the attendant operating experience gained resulted in some design changes and provided the information necessary to fully characterize system performance. Temperature excursions and deviations from preset limits of only a minor nature were encountered during preheat for sodium fill. The addition of the rate alarm feature was beneficial to operation of the preheat system and allowed early detection and correction of impending excursions

  11. Products cooked in preheated versus non-preheated ovens. Baking times, calculated energy consumption, and product quality compared.

    Science.gov (United States)

    Odland, D; Davis, C

    1982-08-01

    Plain muffins, yellow cake, baked custard, apple pie, tuna casserole, frozen tuna casserole, cheese soufflé, and meat loaf were baked in preheated and non-preheated standard gas, continuous-clean gas, standard electric, and self-cleaning electric ovens. Products generally required 5 min. or less extra baking time when cooked in non-preheated rather than in preheated ovens. The variability in baking times often was less between preheated and non-preheated ovens than among oven types. Calculated energy consumption values showed that usually less energy was required to bake products in non-preheated than in preheated ovens; savings averaged about 10 percent. Few significant differences were found in physical measurements or eating quality either between preheated and non-preheated ovens or among oven types. Overall, for the products tested, findings confirmed that preheating the oven is not essential for good product quality and, therefore, is an unnecessary use of energy.

  12. 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.

  13. 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.

  14. Preheating Mechanism in F-term SUSY Hybrid Inflation

    International Nuclear Information System (INIS)

    Mazumdar, Arindam

    2012-01-01

    Supersymmetric F-term hybrid inflation is one of the most popular models of inflation. Preheating process occurs in this model via two different mechanism. Firstly the standard parametric resonance and secondly, the tachyonic preheating. Generally tachyonic preheating dominates the parametric resonance for this type of models. For different values of the parameters of the theory dominance of tachyonic preheating can vary.

  15. Assessment of the energy performance of the solar space system attached to the CE – INCERC Bucharest experimental house – experimental validation

    Directory of Open Access Journals (Sweden)

    Dan CONSTANTINESCU

    2010-01-01

    Full Text Available The INCERC Bucharest experimental house is equipped on the Southern façade with a ventilated solar space. The solar space ensures the ventilation of the entire building at a constant rate of 0.60 exchanges / h during the cold season, by inletting the pre-heated space in the greenhouse space. In the hot season the system ensures the building reversible ventilation by providing the fresh air rate by air suction in the building Northern zone, a consequence of the natural draught effect ensured by the solar space. This report presents the experiments performed in the season 2008-2009 and the experimental validation of the mathematical model used in assessing the solar space energy performance in the heating season.

  16. Solar chimney for the natural ventilation of buildings: simulation and mediation; Chimenea solar para la ventilacion natural de edificios: simulacion y mediacion

    Energy Technology Data Exchange (ETDEWEB)

    Lanceta, D.; Llorente, J.

    2008-07-01

    In this article, the first part of a research project about the modelling of a solar chimney is presented. In this first part, the average ventilation flows measured in an experimental installation have been compared to the results obtained by CFD (Computational Fluid Dynamics) simulations. In order to do so, a solar chimney with a cross-section of 0.78 m x 0.156 m, height 3,6 m, has been constructed. The chimney consists of a glass surface oriented towards the south. The internal (absorber) surface is made of a copper plate, which has been painted black in order to increase the solar absorption. The chimney is connected to a room measuring 5 m x 2.5 m x 2.5 m, from where it extracts air. The comparison of the results obtained by measurements with those obtained by CFD simulations show that computational tools are accurate enough to predict the behaviour of natural buoyancy in this kind of installations. (Author)

  17. : ventilators for noninvasive ventilation

    OpenAIRE

    Fauroux , Brigitte; Leroux , Karl; Desmarais , Gilbert; Isabey , Daniel; Clément , Annick; Lofaso , Frédéric; Louis , Bruno

    2008-01-01

    International audience; The aim of the present study was to evaluate the performance characteristics of all the ventilators proposed for home noninvasive positive-pressure ventilation in children in France. The ventilators (one volume-targeted, 12 pressure-targeted and four dual) were evaluated on a bench which simulated six different paediatric ventilatory patterns. For each ventilator, the quality of the inspiratory and expiratory trigger and the ability to reach and maintain the preset pre...

  18. Elevated temperature forming method and preheater apparatus

    Science.gov (United States)

    Krajewski, Paul E; Hammar, Richard Harry; Singh, Jugraj; Cedar, Dennis; Friedman, Peter A; Luo, Yingbing

    2013-06-11

    An elevated temperature forming system in which a sheet metal workpiece is provided in a first stage position of a multi-stage pre-heater, is heated to a first stage temperature lower than a desired pre-heat temperature, is moved to a final stage position where it is heated to a desired final stage temperature, is transferred to a forming press, and is formed by the forming press. The preheater includes upper and lower platens that transfer heat into workpieces disposed between the platens. A shim spaces the upper platen from the lower platen by a distance greater than a thickness of the workpieces to be heated by the platens and less than a distance at which the upper platen would require an undesirably high input of energy to effectively heat the workpiece without being pressed into contact with the workpiece.

  19. Gravitational radiation from preheating with many fields

    International Nuclear Information System (INIS)

    Jr, John T. Giblin; Price, Larry R.; Siemens, Xavier

    2010-01-01

    Parametric resonances provide a mechanism by which particles can be created just after inflation. Thus far, attention has focused on a single or many inflaton fields coupled to a single scalar field. However, generically we expect the inflaton to couple to many other relativistic degrees of freedom present in the early universe. Using simulations in an expanding Friedmann-Lemaître-Robertson-Walker spacetime, in this paper we show how preheating is affected by the addition of multiple fields coupled to the inflaton. We focus our attention on gravitational wave production — an important potential observational signature of the preheating stage. We find that preheating and its gravitational wave signature is robust to the coupling of the inflaton to more matter fields

  20. Gravitational radiation from preheating with many fields

    Energy Technology Data Exchange (ETDEWEB)

    Jr, John T. Giblin [Department of Physics, Kenyon College, 201 North College Road, Gambier, OH 43022 (United States); Price, Larry R.; Siemens, Xavier, E-mail: giblinj@kenyon.edu, E-mail: larry@gravity.phys.uwm.edu, E-mail: siemens@gravity.phys.uwm.edu [Center for Gravitation and Cosmology, Department of Physics, University of Wisconsin — Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

    2010-08-01

    Parametric resonances provide a mechanism by which particles can be created just after inflation. Thus far, attention has focused on a single or many inflaton fields coupled to a single scalar field. However, generically we expect the inflaton to couple to many other relativistic degrees of freedom present in the early universe. Using simulations in an expanding Friedmann-Lemaître-Robertson-Walker spacetime, in this paper we show how preheating is affected by the addition of multiple fields coupled to the inflaton. We focus our attention on gravitational wave production — an important potential observational signature of the preheating stage. We find that preheating and its gravitational wave signature is robust to the coupling of the inflaton to more matter fields.

  1. Effects of dissipation and fluctuation in preheating

    International Nuclear Information System (INIS)

    Vartuli, Rodrigo; Ramos, Rudnei de O.

    2006-01-01

    In this paper, we study the effects of dissipation and fluctuation in preheating after inflation. The effective equation of motion for a scalar field χ interacting with lighter fields is derived using the field theoretical method of closed time path due to Schwinger, winch is suitable to study nonequilibrium and time dependent process. In this derivation the emergent equation is intrinsically dissipative and stochastic in nature. The resulting dynamics is then studied both analytically and numerically. The results obtained are then discussed for then relevance for the reheating epoch right after an inflationary phase(preheating) for the case of the evolution of the scalar field χ and its decay into fermion. (author)

  2. Ventilation systems

    International Nuclear Information System (INIS)

    Gossler

    1980-01-01

    The present paper deals with - controlled area ventilation systems - ventilation systems for switchgear-building and control-room - other ventilation systems for safety equipments - service systems for ventilation systems. (orig./RW)

  3. Mechanical Ventilation

    Science.gov (United States)

    ... ventilation is a life support treatment. A mechanical ventilator is a machine that helps people breathe when ... to breathe enough on their own. The mechanical ventilator is also called a ventilator , respirator, or breathing ...

  4. 7 CFR 58.919 - Pre-heat, pasteurization.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Pre-heat, pasteurization. 58.919 Section 58.919... Procedures § 58.919 Pre-heat, pasteurization. When pasteurization is intended or required by either the vat... requirements outlined in § 58.128. Pre-heat temperatures prior to ultra pasteurization will be those that have...

  5. Metric preheating and limitations of linearized gravity

    International Nuclear Information System (INIS)

    Bassett, Bruce A.; Tamburini, Fabrizio; Kaiser, David I.; Maartens, Roy

    1999-01-01

    During the preheating era after inflation, resonant amplification of quantum field fluctuations takes place. Recently it has become clear that this must be accompanied by resonant amplification of scalar metric fluctuations, since the two are united by Einstein's equations. Furthermore, this 'metric preheating' enhances particle production, and leads to gravitational rescattering effects even at linear order. In multi-field models with strong preheating (q>>1), metric perturbations are driven non-linear, with the strongest amplification typically on super-Hubble scales (k→0). This amplification is causal, being due to the super-Hubble coherence of the inflaton condensate, and is accompanied by resonant growth of entropy perturbations. The amplification invalidates the use of the linearized Einstein field equations, irrespective of the amount of fine-tuning of the initial conditions. This has serious implications on all scales - from large-angle cosmic microwave background (CMB) anisotropies to primordial black holes. We investigate the (q,k) parameter space in a two-field model, and introduce the time to non-linearity, t nl , as the timescale for the breakdown of the linearized Einstein equations. t nl is a robust indicator of resonance behavior, showing the fine structure in q and k that one expects from a quasi-Floquet system, and we argue that t nl is a suitable generalization of the static Floquet index in an expanding universe. Backreaction effects are expected to shut down the linear resonances, but cannot remove the existing amplification, which threatens the viability of strong preheating when confronted with the CMB. Mode-mode coupling and turbulence tend to re-establish scale invariance, but this process is limited by causality and for small k the primordial scale invariance of the spectrum may be destroyed. We discuss ways to escape the above conclusions, including secondary phases of inflation and preheating solely to fermions. The exclusion principle

  6. Are black holes overproduced during preheating?

    International Nuclear Information System (INIS)

    Suyama, Teruaki; Tanaka, Takahiro; Bassett, Bruce; Kudoh, Hideaki

    2005-01-01

    We provide a simple but robust argument that primordial black hole production generically does not exceed astrophysical bounds during the resonant preheating phase after inflation. This conclusion is supported by fully nonlinear lattice simulations of various models in two and three dimensions which include rescattering but neglect metric perturbations. We examine the degree to which preheating amplifies density perturbations at the Hubble scale and show that, at the end of the parametric resonance, power spectra are universal, with no memory of the power spectrum at the end of inflation. In addition, we show how the probability distribution of density perturbations changes from exponential on very small scales to Gaussian when smoothed over the Hubble scale - the crucial length for studies of primordial black hole formation - hence justifying the standard assumption of Gaussianity

  7. Influence of preheating on grindability of coal

    Science.gov (United States)

    Lytle, J.; Choi, N.; Prisbrey, K.

    1992-01-01

    Enormous quantities of coal must be ground as feed to power generation facilities. The energy cost of grinding is significant at 5 to 15 kWh/ton. If grindability could be increased by preheating the coal with waste heat, energy costs could be reduced. The objective of this work was to determine how grindability was affected by preheating. The method was to use population balance grinding models to interpret results of grinding coal before and after a heat treatment. Simulation of locked cycle tests gave a 40% increase in grindability. Approximately 40% grinding energy saving can be expected. By using waste heat for coal treatment, the targeted energy savings would be maintained. ?? 1992.

  8. Nuclear reactor insulation and preheat system

    International Nuclear Information System (INIS)

    Wampole, N.C.

    1978-01-01

    An insulation and preheat system is disclosed for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the ocmpartment. An external surface of the compartment of enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair

  9. 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.

  10. Spectroscopic Measurements of Target Preheating on OMEGA

    International Nuclear Information System (INIS)

    Elton, R.C.; Griem, H.R.; Iglesias, E.J.

    2000-01-01

    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 ∼ 10 ns prior to onset of the main laser pulse, with a power density ≅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

  11. A Non-Ventilated Solar Façade Concept Based on Selective and Transparent Insulation Material Integration: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Miroslav Čekon

    2017-06-01

    Full Text Available A new solar façade concept based on transparent insulation and a selective absorber is proposed, tested and compared with conventional insulation and a non-selective type of absorber, respectively. The presented study focuses on an experimental non-ventilated solar type of façade exposed to solar radiation both in the laboratory and in outdoor tests. Due to the high solar absorbance level of the façade, high- and low-emissivity contributions were primarily analysed. All of the implemented materials were contrasted from the thermal and optical point of view. An analysis was made of both thermodynamic and steady state procedures affecting the proposed solar façade concept. Experimental full scale tests on real building components were additionally involved during summer monitoring. An indicator of the temperature response generated by solar radiation exposure demonstrates the outdoor performance of the façade is closely related to overheating phenomena. From the thermal point of view, the proposed transparent insulation and selective absorber concept corresponds to the performance of conventional thermal insulation of identical material thickness; however, the non-selective prototype only provides 50% thermal performance. The results of the solar-based experiments show that with a small-scale experimental prototype, approximately no significant difference is measured when compared with a non-selective absorber type. The only difference was achieved at the maximum of 2.5 K, when the lower temperature was obtained in the solar selective concept. At the full-scale outdoor mode, the results indicate a maximum of 3.0 K difference, however the lower temperature achieves a non-selective approach. This solar façade can actively contribute to the thermal performance of building components during periods of heating.

  12. Anaesthesia ventilators

    Directory of Open Access Journals (Sweden)

    Rajnish K Jain

    2013-01-01

    Full Text Available Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV. PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

  13. Anaesthesia ventilators.

    Science.gov (United States)

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-09-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

  14. Anaesthesia ventilators

    Science.gov (United States)

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

  15. Anaesthesia ventilators

    OpenAIRE

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bello...

  16. Sintering uranium oxide using a preheating step

    International Nuclear Information System (INIS)

    Jensen, N.J.; Nivas, Y.; Packard, D.R.

    1977-01-01

    Compacted pellets of uranium oxide or uranium oxide with one or more additives are heated in a kiln in a process having a preheating step, a sintering step, a reduction step, and a cooling step in a controlled atmosphere. The process is practiced to give a range of temperature and atmosphere conditions for obtaining optimum fluoride removal from the compacted pellets along with optimum sintering in a single process. The preheating step of this process is conducted in a temperature range of about 600 0 to about 900 0 C and the pellets are held for at least twenty min, and preferably about 60 min, in an atmosphere having a composition in the range of about 10 to about 75 vol % hydrogen with the balance being carbon dioxide. The sintering step is conducted at a temperature in the range of about 900 0 C to 1500 0 C in the presence of an atmosphere having a composition in the range of about 0.5 to about 90 vol % hydrogen with the balance being carbon dioxide. The reduction step reduces the oxygen to metal ratio of the pellets to a range of about 1.98 to 2.10:1 and this is accomplished by gradually cooling the pellets for about 30 to about 120 min from the temperature of the sintering step to about 1100 0 C in an atmosphere of about 10 to 90 vol % hydrogen with the balance being carbon dioxide. Thereafter the pellets are cooled to about 100 0 C under a protective atmosphere, and in one preferred practice the same atmosphere used in the reduction step is used in the cooling step. The preheating, sintering and reduction steps may also be conducted with their respective atmospheres having an initial additional component of water vapor and the water vapor can comprise up to about 20 vol %

  17. From (p)reheating to nucleosynthesis

    International Nuclear Information System (INIS)

    Jedamzik, Karsten

    2002-01-01

    This paper gives a brief qualitative description of the possible evolution of the early universe between the end of an inflationary epoch and the end of big-bang nucleosynthesis. After a general introduction, establishing the minimum requirements cosmologists impose on this cosmic evolutionary phase, namely, successful baryogenesis, the production of cosmic dark matter and successful light-element nucleosynthesis, a more detailed discussion on some recent developments follows. This latter includes the physics of preheating, the putative production of (alternative) dark matter and the current status of big bang nucleosynthesis

  18. When can preheating affect the CMB?

    Science.gov (United States)

    Tsujikawa, Shinji; Bassett, Bruce A.

    2002-05-01

    We discuss the principles governing the selection of inflationary models for which preheating can affect the CMB. This is a (fairly small) subset of those models which have nonnegligible entropy/isocurvature perturbations on large scales during inflation. We study new models which belong to this class-two-field inflation with negative nonminimal coupling and hybrid/double/supernatural inflation models where the tachyonic growth of entropy perturbations can lead to the variation of the curvature perturbation, /R, on super-Hubble scales. Finally, we present evidence against recent claims for the variation of /R in the absence of substantial super-Hubble entropy perturbations.

  19. Solar radon reduction at six homes in northeast Iowa

    International Nuclear Information System (INIS)

    Rhoads, H.E.; Hoekje, P.L.

    1995-01-01

    Growing concern about radon lung cancer risks, carbon monoxide poisoning, and the sick building syndrome have increased demand for improved indoor air quality. Through solar pre-heating of ventilation air, the Solar Radon Reduction System (SRRS) provides energy benefits with lower installation costs than conventional air-to-air heat exchangers and sub-slab suction approaches. Indoor air quality is improved through dilution, combustion appliance make-up air, pressurization, and reduced radon infiltration through induced-draft solar air collectors drawing supply air from outdoors. Installed at six homes in Waterloo and Cedar Falls, Iowa, the SRRS was found to significantly reduce radon concentrations in all houses with energy benefits and improved overall indoor comfort. Up to 73% reductions from closed house levels as high as 20.9 pCi/L were achieved

  20. Displacement ventilation

    DEFF Research Database (Denmark)

    Kosonen, Risto; Melikov, Arsen Krikor; Mundt, Elisabeth

    The aim of this Guidebook is to give the state-of-the art knowledge of the displacement ventilation technology, and to simplify and improve the practical design procedure. The Guidebook discusses methods of total volume ventilation by mixing ventilation and displacement ventilation and it gives...... insights of the performance of the displacement ventilation. It also shows practical case studies in some typical applications and the latest research findings to create good local micro-climatic conditions....

  1. Design of an atrium for a passive-solar retrofit of an office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J.L.; Hunn, B.D.

    1980-01-01

    The Los Alamos Scientific Laboratory (LASL) has proposed to retrofit one of its administrative office buildings with a solar atrium. A 334 m/sup 2/ courtyard will be enclosed with a roof-mounted system of clerestory windows to maximize winter solar gain. This sunspace will thermally buffer the adjoining offices and also will preheat air supplied to the building's conventional heating, ventilating, and air-conditioning (HVAC) system. The use of the DOE-2 building energy analysis computer program in the design of the solar atrium is described. The results of a series of simulations are reported detailing the tradeoffs inherent in the selection of an optimal glazing area, the maintenance of acceptable comfort levels within the sunspace, and intergration of passive-solar devices with the conventional HVAC system. Potential energy savings are also discussed.

  2. Preheating the universe in hybrid inflation

    CERN Document Server

    García-Bellido, J

    1998-01-01

    One of the fundamental problems of modern cosmology is to explain the origin of all the matter and radiation in the Universe today. The inflationary model predicts that the oscillations of the scalar field at the end of inflation will convert the coherent energy density of the inflaton into a large number of particles, responsible for the present entropy of the Universe. The transition from the inflationary era to the radiation era was originally called reheating, and we now understand that it may consist of three different stages: preheating, in which the homogeneous inflaton field decays coherently into bosonic waves (scalars and/or vectors) with large occupation numbers; backreaction and rescattering, in which different energy bands get mixed; and finally decoherence and thermalization, in which those waves break up into particles that thermalize and acquire a black body spectrum at a certain temperature. These three stages are non-perturbative, non-linear and out of equilibrium, and we are just beginning ...

  3. Application of ground-to-air heat exchanger for preheating of supply air

    Science.gov (United States)

    Sorokins, Juris; Borodinecs, Anatolijs; Zemitis, Jurgis

    2017-10-01

    This study focuses on assessing the contribution of the passive ground-coupled air heat exchanger system to decreasing the energy consumption of air conditioning and ventilation systems for office buildings in the Latvian climate conditions. The theoretical part of the thesis deals with methods of office building ventilation, supply air preheating and heat recovery as well as particularities of using ground-coupled air heat exchangers, their design parameters and their joint impact on the thermal performance. The engineering project part includes a ventilation system for an office building with an integrated ground-coupled air heat exchanger. By simulating energy consumption of the ventilation system for a duration of one year, the thesis analyzes the contribution of the heat exchanger to the overall energy consumption, which totals 9.53 MWh and 4.02 MWh a year, according to the desired parameters of the indoor climate. The possible alternative heat recovery solutions are investigated to reach by European Regional Development Fund project Nr.1.1.1.1/16/A/048 “NEARLY ZERO ENERGY SOLUTIONS FOR UNCLASSIFIED BUILDINGS”.

  4. VENTILATION MODEL

    International Nuclear Information System (INIS)

    V. Chipman

    2002-01-01

    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

  5. [Anesthesia ventilators].

    Science.gov (United States)

    Otteni, J C; Beydon, L; Cazalaà, J B; Feiss, P; Nivoche, Y

    1997-01-01

    To review anaesthesia ventilators in current use in France by categories of ventilators. References were obtained from computerized bibliographic search. (Medline), recent review articles, the library of the service and personal files. Anaesthesia ventilators can be allocated into three groups, depending on whether they readminister expired gases or not or allow both modalities. Contemporary ventilators provide either constant volume ventilation, or constant pressure ventilation, with or without a pressure plateau. Ventilators readministering expired gases after CO2 absorption, or closed circuit ventilators, are either of a double- or a single-circuit design. Double-circuit ventilators, or pneumatical bag or bellows squeezers, or bag-in-bottle or bellows-in-bottle (or box) ventilators, consist of a primary, or driving circuit (bottle or box) and a secondary or patient circuit (including a bag or a bellows or membrane chambers). Bellows-in-bottle ventilators have either standing bellows ascending at expiration, or hanging bellows, descending at expiration. Ascending bellows require a positive pressure of about 2 cmH2O throughout exhalation to allow the bellows to refill. The expired gas volume is a valuable indicator for leak and disconnection. Descending bellows generate a slight negative pressure during exhalation. In case of leak or disconnection they aspirate ambient air and cannot act therefore as an indicator for integrity of the circuit and the patient connection. Closed circuit ventilators with a single-circuit (patient circuit) include a insufflating device consisting either in a bellows or a cylinder with a piston, operated by a electric or pneumatic motor. As the hanging bellows of the double circuit ventilators, they generate a slight negative pressure during exhalation and aspirate ambient air in case of leak or disconnection. Ventilators not designed for the readministration of expired gases, or open circuit ventilators, are generally stand

  6. Ventilation models

    Science.gov (United States)

    Skaaret, Eimund

    Calculation procedures, used in the design of ventilating systems, which are especially suited for displacement ventilation in addition to linking it to mixing ventilation, are addressed. The two zone flow model is considered and the steady state and transient solutions are addressed. Different methods of supplying air are discussed, and different types of air flow are considered: piston flow, plane flow and radial flow. An evaluation model for ventilation systems is presented.

  7. Industrial ventilation

    Science.gov (United States)

    Goodfellow, H. D.

    Industrial ventilation design methodology, using computers and using fluid dynamic models, is considered. It is noted that the design of a ventilation system must be incorporated into the plant design and layout at the earliest conceptual stage of the project. A checklist of activities concerning the methodology for the design of a ventilation system for a new facility is given. A flow diagram of the computer ventilation model shows a typical input, the initialization and iteration loop, and the output. The application of the fluid dynamic modeling techniques include external and internal flow fields, and individual sources of heat and contaminants. Major activities for a ventilation field test program are also addressed.

  8. Gravitational wave production from preheating: parameter dependence

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa, Daniel G. [Theory Division, CERN, 1211 Geneva (Switzerland); Torrentí, Francisco, E-mail: daniel.figueroa@cern.ch, E-mail: f.torrenti@csic.es [Instituto de Física Teórica IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain. (Spain)

    2017-10-01

    Parametric resonance is among the most efficient phenomena generating gravitational waves (GWs) in the early Universe. The dynamics of parametric resonance, and hence of the GWs, depend exclusively on the resonance parameter q . The latter is determined by the properties of each scenario: the initial amplitude and potential curvature of the oscillating field, and its coupling to other species. Previous works have only studied the GW production for fixed value(s) of q . We present an analytical derivation of the GW amplitude dependence on q , valid for any scenario, which we confront against numerical results. By running lattice simulations in an expanding grid, we study for a wide range of q values, the production of GWs in post-inflationary preheating scenarios driven by parametric resonance. We present simple fits for the final amplitude and position of the local maxima in the GW spectrum. Our parametrization allows to predict the location and amplitude of the GW background today, for an arbitrary q . The GW signal can be rather large, as h {sup 2Ω}{sub GW}( f {sub p} ) ∼< 10{sup −11}, but it is always peaked at high frequencies f {sub p} ∼> 10{sup 7} Hz. We also discuss the case of spectator-field scenarios, where the oscillatory field can be e.g. a curvaton, or the Standard Model Higgs.

  9. A New Laser Preheat Protocol For Maglif

    Science.gov (United States)

    Weis, M. R.; Harvey-Thompson, A. J.; Geissel, M.; Jennings, C. A.; Peterson, K. J.; Glinsky, M. E.; Awe, T. J.; Bliss, D. E.; Gomez, M. R.; Harding, E. C.; Hansen, S. B.; Kimmel, M. W.; Knapp, P. F.; Lewis, S. M.; Porter, J. L.; Rochau, G. A.; Schollmeier, M.; Schwarz, J.; Shores, J. E.; Slutz, S. A.; Sinars, D. B.; Smith, I. C.; Speas, C. S.

    2017-10-01

    Previous Magnetized Liner Inertial Fusion experiments at Sandia National Labs have preheated the fuel with the unsmoothed 2 ω Z-Beamlet Laser. A new low intensity laser configuration, using phase plate smoothing and a low-power pulse shape, improved laser propagation and reduced stimulated Brillouin scattering in offline laser experiments. This allows for more efficient use of laser energy and better spot reproducibility. The new laser protocol is estimated to couple at least 650 J to the fuel, sufficient to produce comparable neutron yields with the previous unsmoothed configuration. Mid-Z dopants were also fielded on the underside of the window. Observation of these dopants provided evidence of window material mixing into the fuel with both the unsmoothed and smoothed beam, consistent with MHD simulation predictions. Sandia National Laboratories is a multi-mission laboratory managed and operated by NTESS, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOE's NNSA under contract DE-NA0003525.

  10. Prediction of flame formation in highly preheated air combustion

    International Nuclear Information System (INIS)

    Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool; Katsuki, Masashi

    2008-01-01

    Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

  11. Prediction of flame formation in highly preheated air combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool [Pusan National University, Busan (Korea, Republic of); Katsuki, Masashi [Osaka University, Osaka (Japan)

    2008-11-15

    Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

  12. Numerical Simulation of Anisotropic Preheating Ablative Rayleigh–Taylor Instability

    International Nuclear Information System (INIS)

    Li-Feng, Wang; Wen-Hua, Ye; Ying-Jun, Li

    2010-01-01

    The linear growth rate of the anisotropic preheating ablative Rayleigh–Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T) = κ SH [1 + f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse [Phys. Rev. Lett. 98 (2007) 245001]. (physics of gases, plasmas, and electric discharges)

  13. Numerical simulation of anisotropic preheating ablative Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Wang Lifeng; Ye Wenhua; Li Yingjun

    2010-01-01

    The linear growth rate of the anisotropic preheating ablative Rayleigh-Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T)=κ SH [1+f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse. (authors)

  14. Effect of inflation on parametric resonance during preheating

    International Nuclear Information System (INIS)

    Hirai, Shiro

    2002-01-01

    The effect of inflation on parametric resonance during preheating is investigated. The behaviour of the preheating scalar field during inflation is investigated and is found to become squeezed in cases ranging from small-scale cases to large-scale cases. However, the positive-frequency solution is usually adopted in the initial condition of the scalar field at preheating. Although large squeezing occurs during inflation, the difference in the comoving occupation number of particles n k between two initial conditions is shown to be not so large. Rather, the ratio n k varies from 0.2 to 5.0, depending on k. In order to clarify this situation, we introduce the squeeze formulation. The squeeze parameters r and φ are calculated not only in preheating, but also in inflation. Since the squeeze parameters are calculated from inflation to preheating, we can clarify the behaviour of the parametric resonance. In preheating, the behaviour of r is shown to remain relatively unchanged with respect to k; however, the squeeze angle φ displays different behaviour for large-scale cases and small-scale cases

  15. Behavior of the turbine - regenerating preheaters functional assembly

    International Nuclear Information System (INIS)

    Bigu, Melania; Nita, Iulian Pavel; Tenescu, Mircea

    2004-01-01

    In the classical calculation of pressure distribution in the turbine-regenerating heaters' assembly a uniform distribution of feedwater enthalpy rise at each regenerating preheating step is usually assumed. This is accurately enough as a basis of designing of the preheating installation operating at rated power regime. But at partial regimes this is not totally valid since the preheaters are already shaped and the quasi-equal distribution does not satisfy the equation system describing the heat transfer correlations in these installations. A more detailed analysis shows that pressure in the feeding line preheaters and the bleeding steam flow rates at the turbine outlets are described physically by solving simultaneously the equations of hydrodynamic flow through the turbine and the equations of the heat transfer in the preheaters of the feedwater preheating line. This work approaches this more accurate solving method at least from a theoretical standing point; two cases are illustrated in the annexes of the work: a case of a secondary circuit with a single regenerating inlet and a case with two regenerating inlets. A classical - Panzer method of transformation of a many regenerative stages scheme may lead to one or another of the above cases. (authors)

  16. Solar project description for homes by Marilynn multi-family residence, Albuquerque, New Mexico

    Science.gov (United States)

    Moore, D.

    1981-03-01

    The system is designed to provide solar energy for space heating and preheating DHW. Solar energy is collected by 18 liquid flat plate collectors with a gross area of 346 square feet. Solar energy is transferred from the collector array to a 1000 gallon storage tank. Freeze protection is provided by a 50% ethylene glycol and 50% water. Solar energy is delivered to a liquid-to-air heat exchanger in the space heating subsystem in order to preheat outside air for the heat pump. Preheated city water is stored in a 30 gallon preheat storage tank and supplied, on demand, to a conventional 40 gallon DHW tank.

  17. Mine ventilation engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hall, C.J.

    1981-01-01

    This book on mine ventilation covers psychometrics, airflow through roadways and ducts, natural ventilation, fans, instruments, ventilation surveys, auxiliary ventilation, air quality, and planning and economics.

  18. Noninvasive ventilation.

    Science.gov (United States)

    Rabatin, J T; Gay, P C

    1999-08-01

    Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

  19. 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.

  20. 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...

  1. 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.

  2. 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)

    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.

  3. Susceptibility of CANDU steam generator preheater to cavitation erosion

    International Nuclear Information System (INIS)

    Laroche, S.L.; Sun, L.; Pietralik, J.M.

    2012-01-01

    In 2009, Darlington Steam Generator (SG) tube inspections revealed some tubes had degraded in the preheater. The tube degradation occurred at the clearance gap between the tube and the preheater baffle and reached up to 50% through-wall depth at the baffles in the middle portion of the preheater. The general pattern of the damage and the elemental composition analysis suggested that the degradation was the result of a hydrodynamic process, such as cavitation erosion. Cavitation erosion occurs when vapour bubbles exist or form in the flowing liquid and then these bubbles collapse violently in the vicinity of the wall. These bubbles collapse when steam bubbles contact water that is sufficiently subcooled, below the saturation temperature. In the gap between the tube and the preheater baffle, low flow will exist due to the pressure difference across the baffle plate. In addition, heat transfer occurs from the primary-side fluid to the secondary-side fluid within this clearance gap that is driven by the primary-to-secondary temperature difference. Factors, such as the tube position in the baffle hole and fouling, influence the local conditions and can cause subcooled boiling that result in cavitation. This paper presents a study of flow and heat transfer phenomena to determine the factors contributing to cavitation erosion in SG preheaters. The analysis used the THIRST1 code for a 3-dimensional thermalhydraulic simulation of the steam generators and the ANSYS FLUENT®2 code for detailed calculations of flow and heat transfer in the clearance gaps. This study identifies that tubes in the preheater region are susceptible to cavitation erosion and indicates that this area should be part of the station inspection program because, regardless of preheater design, some tubes may experience the thermalhydraulic conditions and undergo degradations similar to those observed for the tubes in Darlington SGs. (author)

  4. 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-to-un...

  5. Behovstyret ventilation

    DEFF Research Database (Denmark)

    Afshari, Alireza; Heiselberg, Per; Reinhold, Claus

    2010-01-01

    I en nylig afsluttet undersøgelse er der udført en række målinger på otte udvalgte børneinstitutioner. Fire af disse med mekanisk ventilation og fire med naturlig ventilation. Formålet er at udvide den erfaringsbaserede viden om funktionen af naturlige og mekaniske ventilationsløsninger i...

  6. Ventilation Model

    International Nuclear Information System (INIS)

    Yang, H.

    1999-01-01

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future

  7. 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.

  8. 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......-of-the-art of ventilative cooling potentials and limitations, its consideration in current energy performance regulations, available building components and control strategies and analysis methods and tools. In addition, the report provides twenty six examples of operational buildings using ventilative cooling ranging from...

  9. Apartment building built to passive-house standard with solar balanced ventilation system; Mehrfamilien-Passivhaus mit solarem Luftsystem. Lueftung/Luftheizung/WRG/Solarfassade an der Rychenbergstrasse, Winterthur - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Guetermann, A.

    2002-04-15

    This final report for the Swiss Federal Office of Energy (SFOE) deals with an apartment building in Winterthur, Switzerland, built to passive-house standards and equipped with a solar balanced ventilation system. The building and its convective solar facade are described, as are the fan-assisted, balanced ventilation systems used. The operation of the systems in winter, during transitional periods and in summer is discussed. Domestic hot water preparation is looked at. The energy balance of the building is examined, as is the economic viability of the energy systems. The building, its energy installations and the measurement concept used are considered in detail. Finally, the findings of the study are summarised and commented on.

  10. 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...

  11. 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....

  12. The effect of preheating on the IRSL signal from feldspar

    DEFF Research Database (Denmark)

    Murray, A.S.; Buylaert, J.P.; Thomsen, Kristina Jørkov

    2009-01-01

    between the loss of blue IRSL and TL signals with preheating, and the effect of prior IRSL on the TL signal. Using IRSL measured at 50 °C and a SAR protocol, we then examine the dependence on preheat temperature of equivalent dose (De), laboratory fading rate (g), and the resulting luminescence age, from...... is consistent with a kinetic analysis of sensitivity-corrected IRSL data. The corollary to our observations is that shallow (unstable) traps do not give rise to a significant IRSL signal....

  13. Effects of Preheat on Weldments of NICOP Steel.

    Science.gov (United States)

    1983-09-01

    percent Nital solution (nitric acid (HNO3) ,* and ethanol (C2HsOH) which revealed the weld area, heat affected zone and base metal. A section 25.2mm (1 inch...electrolyte, consisting of 10% per- cloric acid (HC104 ) and 90% methanal (CH30H) was maintained at a temperature of -450C (-49 0 F). The Polipower was set...Preheated Weidment. N on Non-Preheated Weidment. Figre3. Loaton o McrhadnssTrvese I17 ~.4. .9 G° s s E 43 C 0 CL 44’ 00 Hda *SBUPJQH Figure 4. Comparison

  14. Feed water pre-heater with two steam spaces

    International Nuclear Information System (INIS)

    Tratz, H.; Kelp, F.; Netsch, E.

    1976-01-01

    A feed water pre-heater for the two stage heating of feed water by condensing steam, having a low installed height is described, which can be installed in the steam ducts of turbines of large output, as in LWRs in nuclear power stations. The inner steam space is closed on one side by the water vessel, while the tubes of the inner steam space go straight from the water vessel, and the tubes of the outer steam space are bent into a U shape and open out into the water vessel. The two-stage preheater is thus surrounded by feedwater in two ways. (UWI) [de

  15. Gravity waves from tachyonic preheating after hybrid inflation

    Energy Technology Data Exchange (ETDEWEB)

    Dufaux, Jean-Francois [Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Felder, Gary [Department of Physics, Clark Science Center, Smith College, Northampton, MA 01063 (United States); Kofman, Lev [CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Navros, Olga, E-mail: jeff.dufaux@uam.es, E-mail: gfelder@email.smith.edu, E-mail: kofman@cita.utoronto.ca, E-mail: navros@email.unc.edu [Department of Mathematics, University of North Carolina Chapel Hill, CB3250 Philips Hall, Chapel Hill, NC 27599 (United States)

    2009-03-15

    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.

  16. Method for pre-heating lmfbr type reactors

    International Nuclear Information System (INIS)

    Yokozawa, Atsushi; Kataoka, Hajime.

    1978-01-01

    Purpose: To enable pre-heating for the inside of the reactor container and the inside of the coolant recycling system with no additional facilities. Method: The coolant recycling system is composed of a heat exchanger, a mechanical pump, a check valve, a flow meter or the like and it is connected in series by way of a pipe line to a reactor container. The mechanical pump is used as a gas recycling device upon pre-heating and it is designed so that a blower such as a fan can be replaced for the impeller of the pump. The inside of the reactor container and the inside of the coolant recycling system is at first filled with an inert gas such as for use with cover gas. Then, nuclear fuels are loaded to attain criticality. Simultaneously, the blower is started and the control rods are operated while cooling the nuclear fuel with the inert gas thus to obtain heat required for pre-heating the pipe line or the like from the nuclear fuels. After the completion of the pre-heating, the liquid metal is charged. (Ikeda, J.)

  17. Constraints on variations in inflaton decay rate from modulated preheating

    Energy Technology Data Exchange (ETDEWEB)

    Mazumdar, Arindam [Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-64 (India); Modak, Kamakshya Prasad, E-mail: arindam.mazumdar@saha.ac.in, E-mail: kamakshya.modak@saha.ac.in [Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-64 (India)

    2016-06-01

    Modulated (p)reheating is thought to be an alternative mechanism for producing super-horizon curvature perturbations in CMB. But large non-gaussianity and iso-curvature perturbations produced by this mechanism rule out its acceptability as the sole process responsible for generating CMB perturbations. We explore the situation where CMB perturbations are mostly generated by usual quantum fluctuations of inflaton during inflation, but a modulated coupling constant between inflaton and a secondary scalar affects the preheating process and produces some extra curvature perturbations. If the modulating scalar field is considered to be a dark matter candidate, coupling constant between the fields has to be unnaturally fine tuned in order to keep the local-form non-gaussianity and the amplitude of iso-curvature perturbations within observational limit; otherwise parameters of the models have to be tightly constrained. Those constraints imply that the curvature perturbations generated by modulated preheating should be less than 15% of the total observed CMB perturbations. On the other hand if the modulating scalar field is not a dark matter candidate, parameters of the models could not be constrained, but the constraints on the maximum amount of the curvature perturbations coming from modulated preheating remain valid.

  18. Constraints on variations in inflaton decay rate from modulated preheating

    International Nuclear Information System (INIS)

    Mazumdar, Arindam; Modak, Kamakshya Prasad

    2016-01-01

    Modulated (p)reheating is thought to be an alternative mechanism for producing super-horizon curvature perturbations in CMB. But large non-gaussianity and iso-curvature perturbations produced by this mechanism rule out its acceptability as the sole process responsible for generating CMB perturbations. We explore the situation where CMB perturbations are mostly generated by usual quantum fluctuations of inflaton during inflation, but a modulated coupling constant between inflaton and a secondary scalar affects the preheating process and produces some extra curvature perturbations. If the modulating scalar field is considered to be a dark matter candidate, coupling constant between the fields has to be unnaturally fine tuned in order to keep the local-form non-gaussianity and the amplitude of iso-curvature perturbations within observational limit; otherwise parameters of the models have to be tightly constrained. Those constraints imply that the curvature perturbations generated by modulated preheating should be less than 15% of the total observed CMB perturbations. On the other hand if the modulating scalar field is not a dark matter candidate, parameters of the models could not be constrained, but the constraints on the maximum amount of the curvature perturbations coming from modulated preheating remain valid.

  19. Gauge-preheating and the end of axion inflation

    Energy Technology Data Exchange (ETDEWEB)

    Adshead, Peter; Sfakianakis, Evangelos I. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Giblin, John T. Jr.; Scully, Timothy R., E-mail: adshead@illinois.edu, E-mail: giblinj@kenyon.edu, E-mail: tscully2@illinois.edu, E-mail: esfaki@illinois.edu [Department of Physics, Kenyon College, 201 North College Rd, Gambier, Ohio 43022 (United States)

    2015-12-01

    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{sup 2φ2} 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 transfers all of its energy to the gauge fields within a few oscillations. In most cases, we find that the gauge fields on sub-horizon scales end preheating in an unpolarized state due to the existence of strong rescattering between the inflaton and gauge-field 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.

  20. Gauge-preheating and the end of axion inflation

    International Nuclear Information System (INIS)

    Adshead, Peter; Sfakianakis, Evangelos I.; Giblin, John T. Jr.; Scully, Timothy R.

    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 2φ2 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 transfers all of its energy to the gauge fields within a few oscillations. In most cases, we find that the gauge fields on sub-horizon scales end preheating in an unpolarized state due to the existence of strong rescattering between the inflaton and gauge-field 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

  1. Theory and numerics of gravitational waves from preheating after inflation

    International Nuclear Information System (INIS)

    Dufaux, Jean-Francois; Kofman, Lev; Bergman, Amanda; Felder, Gary; 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 and the frequency of its peak depend in a relatively simple way on the characteristic spatial scale amplified during preheating. We then estimate the peak frequency and amplitude of the spectrum produced in two models of preheating after hybrid inflation, which for some parameters may be relevant for gravity-wave interferometric experiments

  2. Study on the preheating duration of Cu{sub 2}SnS{sub 3} thin films using RF magnetron sputtering technique for photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuchen; He, Jun; Li, Xinran; Chen, Ye; Sun, Lin, E-mail: lsun@ee.ecnu.edu.cn; Yang, Pingxiong; Chu, Junhao

    2016-04-25

    Cu{sub 2}SnS{sub 3} (CTS) thin films are prepared by sulfurization the stacked metallic precursors deposited by raido-frequency magnetron sputtering method on molybdenum-coated soda lime glass substrates. The details of sulfurization process and the effect of preheating duration on the properties of CTS thin films have been investigated. It is found that the content of element tin strongly depend on the preheating duration. X-ray diffraction patterns identify that the CTS thin films exhibit the monoclinic structure. Raman scattering spectra make a further confirmation for the crystal structure. Fourier transform infrared reflectance spectroscopy (FTIR) is first used to study the properties of CTS thin films. The assigned active modes in Raman scattering spectra is consistent with the analysis in FTIR. Morphology analysis reveals long preheating duration would make the quality of films deteriorate. The thin film solar cell (TFSC) fabricated using the CTS absorber layer synthesized at preheating duration of 15 min shows that a power conversion efficiency up to 0.76% for a 0.19 cm{sup 2} area. The electrical characterization of CTS TFSC is first studied by electrochemical impedance spectroscopy, which implies the existence of MoS{sub x} and defects in the CTS/CdS interface. - Highlights: • CTS thin films and solar cells prepared by RF magnetron sputtering. • Preheating duration is a critical way to remain the Sn content in CTS thin film. • XRD, Raman, FTIR and XPS confirmed the single phase of CTS thin film. • The device characterization of CTS solar cell has been systematically investigated.

  3. Liquid ventilation.

    Science.gov (United States)

    Sarkar, Suman; Paswan, Anil; Prakas, S

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. 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 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. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported.

  4. Low-energy mechanical ventilation

    DEFF Research Database (Denmark)

    Andersen, Claus Wessel; Hviid, Christian Anker

    2014-01-01

    and with as little energy consumption as 41.1 kWh/m2/year including heating and all building services with no use of renewable energy such as PVcells or solar heating. One of the key means of reaching the objectives was to implement mechanical ventilation with low pressure loss and therefore low energy consumption....... The project consists of two buildings, building one is 6 stories high, and building two is 4 stories high. The buildings have a gross area of 50,500 m2 including underground parking. The ventilation and indoor climate concept was to use mechanical ventilation together with mechanical cooling and fanassisted......, with an average of 1.1 kJ/m3. The yearly mean SFP based on estimated runtime is approx. 0.8 kJ/m3. The case shows the unlocked potential that lies within mechanical ventilation for nearzero energy consuming buildings....

  5. Personalized ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2004-01-01

    microenvironment. Furthermore, HVAC systems should be designed to protect occupants from airborne transmission of infectious agents that may be present in exhaled air. Personalized ventilation is a new development in the field of HVAC and has the potential to fulfill the above requirements. This paper reviews...... 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...

  6. On the generation of a non-gaussian curvature perturbation during preheating

    Energy Technology Data Exchange (ETDEWEB)

    Kohri, Kazunori; Lyth, David H. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Valenzuela-Toledo, Cesar A., E-mail: k.kohri@lancaster.ac.uk, E-mail: d.lyth@lancaster.ac.uk, E-mail: cavalto@ciencias.uis.edu.co [Escuela de Física, Universidad Industrial de Santander, Ciudad Universitaria, Bucaramanga (Colombia)

    2010-02-01

    The perturbation of a light field might affect preheating and hence generate a contribution to the spectrum and non-gaussianity of the curvature perturbation ζ. The field might appear directly in the preheating model (curvaton-type preheating) or indirectly through its effect on a mass or coupling (modulated preheating). We give general expressions for ζ based on the δN formula, and apply them to the cases of quadratic and quartic chaotic inflation. For the quadratic case, curvaton-type preheating is ineffective in contributing to ζ, but modulated preheating can be effective. For quartic inflation, curvaton-type preheating may be effective but the usual δN formalism has to be modified. We see under what circumstances the recent numerical simulation of Bond et al. [0903.3407] may be enough to provide a rough estimate for this case.

  7. On the generation of a non-gaussian curvature perturbation during preheating

    International Nuclear Information System (INIS)

    Kohri, Kazunori; Lyth, David H.; Valenzuela-Toledo, Cesar A.

    2010-01-01

    The perturbation of a light field might affect preheating and hence generate a contribution to the spectrum and non-gaussianity of the curvature perturbation ζ. The field might appear directly in the preheating model (curvaton-type preheating) or indirectly through its effect on a mass or coupling (modulated preheating). We give general expressions for ζ based on the δN formula, and apply them to the cases of quadratic and quartic chaotic inflation. For the quadratic case, curvaton-type preheating is ineffective in contributing to ζ, but modulated preheating can be effective. For quartic inflation, curvaton-type preheating may be effective but the usual δN formalism has to be modified. We see under what circumstances the recent numerical simulation of Bond et al. [0903.3407] may be enough to provide a rough estimate for this case

  8. Production of gravitational waves during preheating with nonminimal coupling

    Science.gov (United States)

    Fu, Chengjie; Wu, Puxun; Yu, Hongwei

    2018-04-01

    We study the preheating and the in-process production of gravitational waves (GWs) after inflation in which the inflaton is nonminimally coupled to the curvature in a self-interacting quartic potential with the method of lattice simulation. We find that the nonminimal coupling enhances the amplitude of the density spectrum of inflaton quanta, and as a result, the peak value of the GW spectrum generated during preheating is enhanced as well and might reach the limit of detection in future GW experiments. The peaks of the GW spectrum not only exhibit distinctive characteristics as compared to those of minimally coupled inflaton potentials but also imprint information on the nonminimal coupling and the parametric resonance, and thus the detection of these peaks in the future will provide us a new avenue to reveal the physics of the early universe.

  9. 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...

  10. 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...

  11. Thermographic study of the preheating plugs in diesel engines

    OpenAIRE

    Royo Pastor, Rafael; Albertos Arranz, M.A.; CÁRCEL CUBAS, JUAN ANTONIO; Payá Herrero, Jorge

    2012-01-01

    The use of direct injection diesel engines has been widely applied during the past ten years. In such engines, the preheating plugs are a key element which has a significant contribution in the pollutant emissions. In this paper, two different plug designs from Renault are analyzed. The new plug reduces substantially the required electrical consumption. Nevertheless, the pollutant emissions are higher (fundamentally CO and HCs) and hereby a thorough analysis is required to underst...

  12. DEFROST: a new code for simulating preheating after inflation

    International Nuclear Information System (INIS)

    Frolov, Andrei V

    2008-01-01

    At the end of inflation, dynamical instability can rapidly deposit the energy of homogeneous cold inflaton into excitations of other fields. This process, known as preheating, is rather violent, inhomogeneous and non-linear, and has to be studied numerically. This paper presents a new code for simulating scalar field dynamics in an expanding universe written for that purpose. Compared to available alternatives, it significantly improves both the speed and the accuracy of calculations, and is fully instrumented for 3D visualization. We reproduce previously published results on preheating in simple chaotic inflation models, and further investigate non-linear dynamics of the inflaton decay. Surprisingly, we find that the fields do not 'want' to thermalize in quite the way that one would think. Instead of directly reaching equilibrium, the evolution appears to be stuck in a rather simple but quite inhomogeneous state. In particular, a one-point distribution function of total energy density appears to be universal among various two-field preheating models, and is exceedingly well described by a log-normal distribution. It is tempting to attribute this state to scalar field turbulence

  13. CFD modeling of fouling in crude oil pre-heaters

    International Nuclear Information System (INIS)

    Bayat, Mahmoud; Aminian, Javad; Bazmi, Mansour; Shahhosseini, Shahrokh; Sharifi, Khashayar

    2012-01-01

    Highlights: ► A conceptual CFD-based model to predict fouling in industrial crude oil pre-heaters. ► Tracing fouling formation in the induction and developing continuation periods. ► Effect of chemical components, shell-side HTC and turbulent flow on the fouling rate. - Abstract: In this study, a conceptual procedure based on the computational fluid dynamic (CFD) technique has been developed to predict fouling rate in an industrial crude oil pre-heater. According to the developed CFD concept crude oil was assumed to be composed of three pseudo-components comprising of petroleum, asphaltene and salt. The binary diffusion coefficients were appropriately categorized into five different groups. The species transport model was applied to simulate the mixing and transport of chemical species. The possibility of adherence of reaction products to the wall was taken into account by applying a high viscosity for the products in competition with the shear stress on the wall. Results showed a reasonable agreement between the model predictions and the plant data. The CFD model could be applied to new operating conditions to investigate the details of the crude oil fouling in the industrial pre-heaters.

  14. Wind Extraction for Natural Ventilation

    Science.gov (United States)

    Fagundes, Tadeu; Yaghoobian, Neda; Kumar, Rajan; Ordonez, Juan

    2017-11-01

    Due to the depletion of energy resources and the environmental impact of pollution and unsustainable energy resources, energy consumption has become one of the main concerns in our rapidly growing world. Natural ventilation, a traditional method to remove anthropogenic and solar heat gains, proved to be a cost-effective, alternative method to mechanical ventilation. However, while natural ventilation is simple in theory, its detailed design can be a challenge, particularly for wind-driven ventilation, which its performance highly involves the buildings' form, surrounding topography, turbulent flow characteristics, and climate. One of the main challenges with wind-driven natural ventilation schemes is due to the turbulent and unpredictable nature of the wind around the building that impose complex pressure loads on the structure. In practice, these challenges have resulted in founding the natural ventilation mainly on buoyancy (rather than the wind), as the primary force. This study is the initial step for investigating the physical principals of wind extraction over building walls and investigating strategies to reduce the dependence of the wind extraction on the incoming flow characteristics and the target building form.

  15. Solar energy system performance evaluation: Seasonal report for Contemporary-Manchester, Manchester, New Hampshire

    Science.gov (United States)

    1980-01-01

    The operational and thermal performance of the solar energy system, Contemporary-Manchester, is described. The system was designed by Contemporary Systems Incorporated to provide space heating and domestic hot water preheating for a three story dwelling located on the New Hampshire Vocational Technical College campus, Manchester, New Hampshire. The net fossil energy savings for the period from March, 1979 to February, 1980 was 14.52 million Btu. However, the performance of the system must be degraded due to the fact that the building was unoccupied throughout the data assessment and analysis period. The unoccupied status prevented the normal adjustment of heating and ventilating controls for maintenance of comfort levels within the building. This lack of occupancy also prevented the typical family hot water usage, which would have allowed for more realistic evaluation of the hot water subsystem.

  16. Regenerative heat exchanger for cowper combustion air preheating

    Energy Technology Data Exchange (ETDEWEB)

    Molenaar, R.; Otterbach, G.

    1986-01-13

    The waste gas leaving cowper units at a temperature of 200/sup 0/C to 300/sup 0/C was previously discharged unused into the atmosphere. By providing a suitable heat exchanger, the heat content of the waste gas can be used to preheat the combustion agents of cowpers to an extent allowing both to increase the efficiency of cowpers and to decrease the amount of rich gas required. The operating results confirm to a large extent the theoretical assumptions and calculations. One may therefore expect the entire investment to have been fully redeemed in a little more than two years. (orig.).

  17. Bruce NGS A Unit 4 preheater divider plate failure

    International Nuclear Information System (INIS)

    Landridge, M.; McInnes, D.

    1995-01-01

    On May 19, 1995, without any prior operational indications, Bruce A discovered preheater divider plate damage in Unit 4 that had the potential to have a major impact on the continued safe operation of the station. Further investigations indicated that Unit 4 may have been operating with this damage for as long as ten years. In the two months following the discovery, Bruce A has procured and replaced the 4 divider plates, located most of the missing pieces, retrieved pieces from the PHT system, investigated historical operational information, performed detailed analytical investigations, investigated root cause, performed in-situ and mock-up testing, updated operational procedures and installed DP monitoring equipment

  18. Fresh fuel pre-heating device in reactor facility

    International Nuclear Information System (INIS)

    Samejima, Asakuni.

    1988-01-01

    Purpose: To simplify the structure of a fresh nuclear fuel pre-heating device and improve the reliability to gas supply. Constitution: Fresh fuels taken out from a fresh fuel stredge rack and contained in a fuel strage pipe of a fuel transportation cask are pre-heated at the pre-stage of transfer by sending heating gases from the outside. Gas outlet pipes of the device are led out from the lower portion of the strage pipe, disposed side by side at the top of the strage pipe and opened upwardly. Further, gas supply pipes are connected to the inside of a movable guiding cylinder on the side of the floor surface and the opening end of return pipes are opposed to the exit opening end of the strage pipe. In such a constitution, a gas recycling loop can be formed between the strage pipe and the gas heating device by way of the movable guiding cylinder only by the operation of combining the fuel strage pipe of the transportation cask and the movable guiding pipe disposed on the side of the floor surface. Thus, the coupling structure is facilitated, the connection operation can surely be conducted to improve the reliability as compared with the conventional case. (Horiuchi, T.)

  19. Ventilator-driven xenon ventilation studies

    International Nuclear Information System (INIS)

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-01-01

    A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration

  20. Effects of substrate preheating during direct energy deposition on microstructure, hardness, tensile strength, and notch toughness

    Science.gov (United States)

    Baek, Gyeong Yun; Lee, Ki Yong; Park, Sang Hu; Shim, Do Sik

    2017-11-01

    This study examined the effects of substrate preheating for the hardfacing of cold-press dies using the high-speed tool steel AISI M4. The preheating of the substrate is a widely used technique for reducing the degree of thermal deformation and preventing crack formation. We investigated the changes in the metallurgical and mechanical properties of the high-speed tool steel M4 deposited on an AISI D2 substrate with changes in the substrate preheating temperature. Five preheating temperatures (100-500 °C; interval of 100 °C) were selected, and the changes in the temperature of the substrate during deposition were observed. As the preheating temperature of the substrate was increased, the temperature gradient between the melting layer and the substrate decreased; this prevented the formation of internal cracks, owing to thermal stress relief. Field-emission scanning electron microscopy showed that a dendritic structure was formed at the interface between the deposited layer and the substrate while a cellular microstructure was formed in the deposited layer. As the preheating temperature was increased, the sizes of the cells and precipitated carbides also increased. Furthermore, the hardness increased slightly while the strength and toughness decreased. Moreover, the tensile and impact properties deteriorated rapidly at excessively high preheating temperatures (greater than 500 °C). The results of this study can be used as preheating criteria for achieving the desired mechanical properties during the hardfacing of dies and molds.

  1. 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...

  2. Diffuse ceiling ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen

    Diffuse ceiling ventilation is an innovative ventilation concept where the suspended ceiling serves as air diffuser to supply fresh air into the room. Compared with conventional ventilation systems, diffuse ceiling ventilation can significantly reduce or even eliminate draught risk due to the low...

  3. Reheating the D-brane universe via instant preheating

    International Nuclear Information System (INIS)

    Panda, Sudhakar; Sami, M.; Thongkool, I.

    2010-01-01

    We investigate a possibility of reheating in a scenario of D-brane inflation in a warped deformed conifold background which includes perturbative corrections to throat geometry sourced by a chiral operator of dimension 3/2 in the conformal field theory. The effective D-brane potential, in this case, belongs to the class of nonoscillatory models of inflation for which the conventional reheating mechanism does not work. We find that gravitational particle production is inefficient and leads to reheating temperature of the order of 10 8 GeV. We show that instant preheating is quite suitable to the present scenario and can easily reheat the universe to a temperature which is higher by about 3 orders of magnitude than its counterpart associated with gravitational particle production. The reheating temperature is shown to be insensitive to a particular choice of inflationary parameters suitable to observations.

  4. Variable mechanical ventilation.

    Science.gov (United States)

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  5. VENTILATION NEEDS DURING CONSTRUCTION

    International Nuclear Information System (INIS)

    C.R. Gorrell

    1998-01-01

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options

  6. Solar building construction. Town planning - construction planning. 2. rev. ed.

    International Nuclear Information System (INIS)

    Schempp, D.; Krampen, M.; Moellring, F.

    1994-01-01

    The book discusses the problems of solar energy use under the following aspects: Town planing; Typology of green solar architecture; Typologie of solar architecture; Vegetation in green solar architecture; Planning and simulation; Building materials; Ventilation, illumination; Research projects. (HW) [de

  7. Descriptions and diagrams of the primary and annulus ventilation systems of the double-shell tank farms as of January 1988

    International Nuclear Information System (INIS)

    Blackman, A.E.; Waters, E.D.

    1994-01-01

    This document is a compilation of information describing the ventilation systems of the Double-Shell Tank farms (214-AN, -AP, -AW, -AW, -AY, -AZ, and -SY). A general description of the primary tank and annulus ventilation systems is given along with specific information on the high efficiency particulate air (HEPA) filters, condensers, preheaters, exhaust fans, and piping. This information is considered to be current as of January 1988. 38 refs, 20 figs, 30 tabs

  8. Market development for active solar thermal systems (ASTS) in the institutional, commercial and industrial (ICI) sectors

    International Nuclear Information System (INIS)

    2000-01-01

    The market potential for active solar thermal systems in the institutional, commercial and industrial sectors of the Canadian economy was investigated, the objective being to identify markets and to prepare action plans as the foundation for developing these markets by Natural Resources Canada and the industry. In the process of researching the market, barriers to market development in these sectors of the economy were also identified as well as actions to overcome these barriers. Nine potential applications were modelled to determine their energy, economic and environmental performance. Of these four attractive applications have been selected for more detailed treatment. Separate action plans have been developed for Natural Resources Canada, the Canadian Solar Industries Association and the active solar thermal industry. The close cooperation of all three partners is considered essential for a successful marketing effort. A marketing plan which gives due consideration to the product, planning, packaging, price and promotion, is also considered to be a vital ingredient, as is a meticulous follow-up on 'leads' created by exposure to the target market. Solarwall'TM' for preheating of ventilation air to new school buildings and solar domestic hot water heating for camp grounds have been identified as the most attractive candidates for marketing at this time. Highlights of marketing plans for these two options are included for purposes of illustrating the essential ingredients of marketing plans. 1 fig

  9. Powertrain preheating system of tracked hybrid electric vehicle in cold weather

    International Nuclear Information System (INIS)

    Wang, Rui; Wang, Yichun; Feng, Chaoqing; Zhang, Xilong

    2015-01-01

    In order to make sure that the heavy duty tracked vehicle can work in various conditions, especially severe cold weather, preheating system of powertrain should be adopted, and a novel preheating system is presented for the tracked hybrid electric vehicle (HEV) in which heat is generated by the low-speed drive motor. The new preheating system can meet the need of cold start without adding any additional device. The characteristic of heat generation by motor is tested when the rotor of motor is rotated in very low speed. The heat loss from power cabin to external environment has been simulated, and the relevant test has been done to verify the simulation results. Combining the characteristic of heat generation and heat loss situation about preheating system, the heat transfer model of preheating system was implemented by MATLAB. The total energy required for preheating in different ambient temperature was calculated by this model. The results showed that: the minimum heating power was 70 kW and energy required was about 180 MJ when the HEV worked in −46 °C. If lithium ferrous phosphate (LFP) battery was used in power system, the minimum battery capacity is about 290 A h. - Highlights: • A novel preheating method was proposed for heavy duty tracked HEV. • Thermal energy in preheating system is produced by the PMSM in driving system. • This method can achieve preheating target by its own components without any adding. • Analyzing low temperature performance of power battery and select its capacity.

  10. Measurement of preheat in aluminium target in indirect drive using the SGIII prototype facilities

    International Nuclear Information System (INIS)

    Zhang, C; Zheng, J; Wang, Z B; Liu, H; Peng, X S; Wang, F; Ding, Y K

    2016-01-01

    The velocity interferometer system for any reflector (VISAR) is used to demonstrate preheat effect in aluminium in indirect drive. The rear surface motion prior to shock front was observed and compared with a multi-group calculation. By properly adjusting the hard x-ray portion of the radiation source, the calculated rear surface motion fits well with the experimental results, which gives us confidence to predict the preheated temperature of the sample by hard x-rays. Further, the effect of hohlraum geometry is compared and discussed experimentally. The result suggests gas-filled hohlraum or hohlraum with low Z substrates should be considered to further reduce preheating. (paper)

  11. Analysis of pre-heated fuel combustion and heat-emission dynamics in a diesel engine

    Science.gov (United States)

    Plotnikov, S. A.; Kartashevich, A. N.; Buzikov, S. V.

    2018-01-01

    The article explores the feasibility of diesel fuel pre-heating. The research goal was to obtain and analyze the performance diagrams of a diesel engine fed with pre-heated fuel. The engine was tested in two modes: at rated RPMs and at maximum torque. To process the diagrams the authors used technique developed by the Central Diesel Research Institute (CDRI). The diesel engine’s heat emission curves were obtained. The authors concluded that fuel pre-heating shortened the initial phase of the combustion process and moderated the loads, thus making it possible to boost a diesel engine’s mean effective pressure.

  12. Effect of pre-heat treatment on a Fischer-Tropsch iron catalyst

    International Nuclear Information System (INIS)

    Rao, K.R.P.M.; Huggins, F.E.; Ganguly, B.; Mahajan, V.; Huffman, G.P.; Davis, B.; O'Brien, R.J.; Xu Liguang; Rao, V.U.S.

    1994-01-01

    Moessbauer spectroscopy was used to investigate the effect of heating the Fischer-Tropsch catalyst 100 Fe/5 Cu/4.2 K/24 SiO 2 in two different atmospheres while ramping the temperature of the catalyst from room temperature to 280 C in 5.5 h prior to pretreatment of the catalyst. Preheating in H 2 /CO = 0.7 gave rise to an iron (Fe 2+ ) silicate, while preheating in helium resulted in the formation of ε'-carbide Fe 2.2 C. Iron oxides and χ-carbide Fe 5 C 2 were also formed in both preheat treatments. (orig.)

  13. Calculation and design of natural gas preheater equipments. Berechnung und Auslegung von Erdgas-Vorwaermeanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Fasold, H G [Ruhrgas AG, Essen (Germany); Wahle, H N [Ruhrgas AG, Essen (Germany)

    1994-04-01

    A greatly simplified model of a regulating station - consisting of the station components ''preheater'' and ''control unit'' - is used for the calculation and design of natural gas preheating plants. It is hereby possible to calculate the Joule-Thomson effect which occurs on the expansion of natural gas in the controller, the resulting drop in temperature and the thermal output required to compensate this which is to be supplied to the gas flow by the preheating plant. The calculation method and procedure are explained using a programming flowchart. The computational model presented was converted into a personal computer program, whose functioning is elucidated using a numerical example. (orig.)

  14. Patient-Ventilator Dyssynchrony

    Directory of Open Access Journals (Sweden)

    Elvira-Markela Antonogiannaki

    2017-11-01

    Full Text Available In mechanically ventilated patients, assisted mechanical ventilation (MV is employed early, following the acute phase of critical illness, in order to eliminate the detrimental effects of controlled MV, most notably the development of ventilator-induced diaphragmatic dysfunction. Nevertheless, the benefits of assisted MV are often counteracted by the development of patient-ventilator dyssynchrony. Patient-ventilator dyssynchrony occurs when either the initiation and/or termination of mechanical breath is not in time agreement with the initiation and termination of neural inspiration, respectively, or if the magnitude of mechanical assist does not respond to the patient’s respiratory demand. As patient-ventilator dyssynchrony has been associated with several adverse effects and can adversely influence patient outcome, every effort should be made to recognize and correct this occurrence at bedside. To detect patient-ventilator dyssynchronies, the physician should assess patient comfort and carefully inspect the pressure- and flow-time waveforms, available on the ventilator screen of all modern ventilators. Modern ventilators offer several modifiable settings to improve patient-ventilator interaction. New proportional modes of ventilation are also very helpful in improving patient-ventilator interaction.

  15. arXiv Gravitational wave production from preheating -- parameter dependence

    CERN Document Server

    Figueroa, Daniel G.

    2017-10-31

    Parametric resonance is among the most efficient phenomena generating gravitational waves (GWs) in the early Universe. The dynamics of parametric resonance, and hence of the GWs, depend exclusively on the resonance parameter q. The latter is determined by the properties of each scenario: the initial amplitude and potential curvature of the oscillating field, and its coupling to other species. Previous works have only studied the GW production for fixed value(s) of q. We present an analytical derivation of the GW amplitude dependence on q, valid for any scenario, which we confront against numerical results. By running lattice simulations in an expanding grid, we study for a wide range of q values, the production of GWs in post-inflationary preheating scenarios driven by parametric resonance. We present simple fits for the final amplitude and position of the local maxima in the GW spectrum. Our parametrization allows to predict the location and amplitude of the GW background today, for an arbitrary q. The GW si...

  16. Heating, ventilating, and air-conditioning applications

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This book covers: Comfort air conditioning and heating of residences: Space HVAC systems; Industrial and special air conditioning and ventilation for nuclear facilities, and for mines; Energy sources, such as Geothermal energy, solar utilization, and energy resources; Building operation and maintenance; energy management, and Thermal storage

  17. Mechanical ventilator - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007240.htm Mechanical ventilator - infants To use the sharing features on this page, please enable JavaScript. A mechanical ventilator is a machine that assists with breathing. ...

  18. Learning about ventilators

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000458.htm Learning about ventilators To use the sharing features on this page, ... fixed or changed. How Does Being on a Ventilator Feel? A person receives medicine to remain comfortable ...

  19. Preheat-induced signal enhancement in the infrared stimulated luminescence of young and bleached sediment samples

    International Nuclear Information System (INIS)

    Richardson, C.A.

    2000-01-01

    Natural and laboratory bleached surface and young samples of potassium feldspar sand separates and polymineral silt had their infrared stimulated luminescence (IRSL) signal measured before and after preheating at 220 deg. C for 10 min or 160 deg. C for 16 h. For both preheats, the laboratory bleached sand samples underwent a signal enhancement which was stable with laboratory storage. The youngest samples also showed natural signal enhancement. The silt sample showed no recuperation of bleached signal on preheating, but some in the natural signal. A range of filtered bleaches was applied to one surface sand sample. Signal levels before and after preheating were reduced by filtering out the UV from the bleaching spectrum. The unfiltered bleach, however, most closely reproduced the behaviour of the natural sample

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

    OpenAIRE

    Dolianitis Ioannis; Giannakopoulos Dionysios; Hatzilau Christina-Stavrula; Karellas Sotirios; Kakaras Emmanuil; Nikolova Evelina; Skarpetis Georgios; Christodoulou Nikolaos; Giannoulas Nikolaos; Zitounis Theodoros

    2016-01-01

    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 containe...

  1. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    Science.gov (United States)

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  2. Ventilation of nuclear facilities

    International Nuclear Information System (INIS)

    1982-01-01

    In this work an examination is made of ventilation problems in nuclear installations, of the fuel cycle or the handling of radioactive compounds. The study covers the detection of radioactive aerosols, purification, iodine trapping, ventilation equipment and its maintenance, engineering, safety of ventilation, fire efficiency, operation, regulations and normalization [fr

  3. Microwave pre-heating of natural rubber using a rectangular wave guide (MODE: TE10

    Directory of Open Access Journals (Sweden)

    Doo-ngam, N.

    2007-11-01

    Full Text Available This paper presents an application of microwave radiation for pre-heating of natural rubbercompounding with various sulphur contents. The natural rubber-compounding was pre-heated by microwave radiation using a rectangular wave guide system (MODE: TE10 operating at frequency of 2.45 GHz in which the power can vary from 0 to 1500 W. In the present work, the influence of power input, sample thickness, and sulphur content were examined after applying microwave radiation to the rubber samples. Results are discussed regarding the thermal properties, 3-D network, dielectric properties and chemical structures. From the result, firstly, it was found that microwave radiation can be applied to pre-heating natural rubber-compounding before the vulcanization process. Secondly, microwave radiation was very useful for pre-heating natural rubber-compounding that has a thickness greater than 5mm. Thirdly, crosslinking in natural rubber-compounding may occurs after pre-heating by microwave radiation though Fourier Transform Infrared Spectroscopy(FTIR. Finally, there a little effect of sulphur content on temperature profiles after applying microwave radiation to the natural rubber-compounding. Moreover, natural rubber-compounding without carbon black showed a lower heat absorption compared with natural rubbercompounding filled carbon black. This is due to the difference in dielectric loss factor. This preliminary result will be useful information in terms of microwave radiation for pre-heating natural rubber-compounding and rubber processing in industry.

  4. Optimal Substrate Preheating Model for Thermal Spray Deposition of Thermosets onto Polymer Matrix Composites

    Science.gov (United States)

    Ivosevic, M.; Knight, R.; Kalidindi, S. R.; Palmese, G. R.; Tsurikov, A.; Sutter, J. K.

    2003-01-01

    High velocity oxy-fuel (HVOF) sprayed, functionally graded polyimide/WC-Co composite coatings on polymer matrix composites (PMC's) are being investigated for applications in turbine engine technologies. This requires that the polyimide, used as the matrix material, be fully crosslinked during deposition in order to maximize its engineering properties. The rapid heating and cooling nature of the HVOF spray process and the high heat flux through the coating into the substrate typically do not allow sufficient time at temperature for curing of the thermoset. It was hypothesized that external substrate preheating might enhance the deposition behavior and curing reaction during the thermal spraying of polyimide thermosets. A simple analytical process model for the deposition of thermosetting polyimide onto polymer matrix composites by HVOF thermal spray technology has been developed. The model incorporates various heat transfer mechanisms and enables surface temperature profiles of the coating to be simulated, primarily as a function of substrate preheating temperature. Four cases were modeled: (i) no substrate preheating; (ii) substrates electrically preheated from the rear; (iii) substrates preheated by hot air from the front face; and (iv) substrates electrically preheated from the rear and by hot air from the front.

  5. Ventilation and ventilation/perfusion ratios

    International Nuclear Information System (INIS)

    Valind, S.O.

    1989-01-01

    The thesis is based on five different papers. The labelling of specific tracer compounds with positron emitting radionuclides enables a range of structural, physiological and biochemical parameters in the lung to be measured non-invasively, using positron emission tomography. This concept affords a unique opportunity for in vivo studies of different expressions of pulmonary pathophysiology at the regional level. The present thesis describes the application of positron emission tomography to the measurements of ventilation and ventilation/perfusion ratios using inert gas tracers, neon-19 and nitrogen-13 respectively. The validity of the methods applied was investigated with respect to the transport of inert gas tracers in the human lung. Both ventilation and the ventilation/perfusion ratio may be obtained with errors less than 10 % in the normal lung. In disease, however, errors may increase in those instances where the regional ventilation is very low or the intra-regional gas flow distribution is markedly nonuniform. A 2-3 fold increase in ventilation was demonstrated in normal nonsmoking subjects going from ventral to dorsal regions in the supine posture. These large regional differences could be well explained by the intrinsic elastic properties of lung tissue, considering the gravitational gradient in transpulmonary pressure. In asymptomatic smokers substantial regional ventilatroy abnormalities were found whilst the regional gas volume was similar in smokers and nonsmokers. The uncoupling between ventilation and gas volume probably reflects inflammatory changes in the airways. The regional differences in dV/dt/dQ/dt were relatively small and blood flow was largely matched to ventilation in the supine posture. However, small regions of lung with very low ventilation, unmatched by blood flow commonly exists in the most dependent parts of the lung in both smokers and nonsmokers. (29 illustrations, 7 tables, 113 references)

  6. Application of field synergy principle for optimization fluid flow and convective heat transfer in a tube bundle of a pre-heater

    International Nuclear Information System (INIS)

    Hamid, Mohammed O.A.; Zhang, Bo; Yang, Luopeng

    2014-01-01

    The big problems facing solar-assisted MED (multiple-effect distillation) desalination unit are the low efficiency and bulky heat exchangers, which worsen its systematic economic feasibility. In an attempt to develop heat transfer technologies with high energy efficiency, a mathematical study is established, and optimization analysis using FSP (field synergy principle) is proposed to support meaning of heat transfer enhancement of a pre-heater in a solar-assisted MED desalination unit. Numerical simulations are performed on fluid flow and heat transfer characteristics in a circular and elliptical tube bundle. The numerical results are analyzed using the concept of synergy angle and synergy number as an indication of synergy between velocity vector and temperature gradient fields. Heat transfer in elliptical tube bundle is enhanced significantly with increasing initial velocity of the feed seawater and field synergy number and decreasing of synergy angle. Under the same operating conditions of the two designs, the total average synergy angle is 78.97° and 66.31° in circular and elliptical tube bundle, respectively. Optimization of the pre-heater by FSP shows that in case of elliptical tube bundle design, the average synergy number and heat transfer rate are increased by 22.68% and 35.98% respectively. - Highlights: • FSP (field synergy principle) is used to investigate heat transfer enhancement. • Numerical simulations are performed in circular and elliptical tubes pre-heater. • Numerical results are analyzed using concept of synergy angle and synergy number. • Optimization of elliptical tube bundle by FSP has better performance

  7. Three story residence with solar heat--Manchester, New Hampshire

    Science.gov (United States)

    1981-01-01

    When heat lost through ducts is counted for accurate performance assessment, solar energy supplied 56 percent of building's space heating load. Average outdoor temperature was 53 degrees F; average indoor temperature was 69 degrees F. System operating modes included heating from solar collectors, storing heat, heating from storage, auxiliary heating with oil fired furnace, summer venting, and hot water preheating.

  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. Complications of mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Drašković Biljana

    2011-01-01

    Full Text Available Mechanical ventilation of the lungs, as an important therapeutic measure, cannot be avoided in critically ill patients. However, when machines take over some of vital functions there is always a risk of complications and accidents. Complications associated with mechanical ventilation can be divided into: 1 airway-associated complications; 2 complications in the response of patients to mechanical ventilation; and 3 complications related to the patient’s response to the device for mechanical ventilation. Complications of artificial airway may be related to intubation and extubation or the endotracheal tube. Complications of mechanical ventilation, which arise because of the patient’s response to mechanical ventilation, may primarily cause significant side effects to the lungs. During the last two decades it was concluded that mechanical ventilation can worsen or cause acute lung injury. Mechanical ventilation may increase the alveolar/capillary permeability by overdistension of the lungs (volutrauma, it can exacerbate lung damage due to the recruitment/derecruitment of collapsed alveoli (atelectrauma and may cause subtle damages due to the activation of inflammatory processes (biotrauma. Complications caused by mechanical ventilation, beside those involving the lungs, can also have significant effects on other organs and organic systems, and can be a significant factor contributing to the increase of morbidity and mortality in critically ill of mechanically ventilated patients. Complications are fortunately rare and do not occur in every patient, but due to their seriousness and severity they require extensive knowledge, experience and responsibility by health-care workers.

  10. Evaluation of ventilators for mouthpiece ventilation in neuromuscular disease.

    Science.gov (United States)

    Khirani, Sonia; Ramirez, Adriana; Delord, Vincent; Leroux, Karl; Lofaso, Frédéric; Hautot, Solène; Toussaint, Michel; Orlikowski, David; Louis, Bruno; Fauroux, Brigitte

    2014-09-01

    Daytime mouthpiece ventilation is a useful adjunct to nocturnal noninvasive ventilation (NIV) in patients with neuromuscular disease. The aims of the study were to analyze the practice of mouthpiece ventilation and to evaluate the performance of ventilators for mouthpiece ventilation. Practice of mouthpiece ventilation was assessed by a questionnaire, and the performance of 6 home ventilators with mouthpiece ventilation was assessed in a bench test using 24 different conditions per ventilator: 3 mouthpieces, a child and an adult patient profile, and 4 ventilatory modes. Questionnaires were obtained from 30 subjects (mean age 33 ± 11 y) using NIV for 12 ± 7 y. Fifteen subjects used NIV for > 20 h/day, and 11 were totally ventilator-dependent. The subject-reported benefits of mouthpiece ventilation were a reduction in dyspnea (73%) and fatigue (93%) and an improvement in speech (43%) and eating (27%). The bench study showed that none of the ventilators, even those with mouthpiece ventilation software, were able to deliver mouthpiece ventilation without alarms and/or autotriggering in each condition. Alarms and/or ineffective triggering or autotriggering were observed in 135 of the 198 conditions. The occurrence of alarms was more common with a large mouthpiece without a filter compared to a small mouthpiece with a filter (P ventilator. Subjects are satisfied with mouthpiece ventilation. Alarms are common with home ventilators, although less common in those with mouthpiece ventilation software. Improvements in home ventilators are needed to facilitate the expansion of mouthpiece ventilation. Copyright © 2014 by Daedalus Enterprises.

  11. Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

    Directory of Open Access Journals (Sweden)

    Matthias Richard Kramer

    2016-01-01

    Full Text Available To test the impact of preheating (25, 37, 54, or 68 °C of TetricEvoCeram (TEC, FiltekSupremeXT (FSXT, and Venus (V on flexural strength (FS, shear bond strength (SBS and interfacial tension (IFT. FS was tested with TEC and FSXT. For SBS, glass-ceramic and human dentin substrate were fabricated and luted with the preheated resin composite (RC. SBSs of 1500 thermal cycled specimens were measured. For IFT, glass slides covered with the non-polymerized RC were prepared and contact angles were measured. Data were analyzed using 2/1-way ANOVA with Scheffé-test, and t-test (p < 0.05. Preheated TEC (37–68 °C showed higher FS compared to the control-group (25 °C (p < 0.001. FSXT presented higher FS than TEC (p < 0.001. For SBS to dentin higher values for FSXT than TEC were found. The preheating temperature showed no impact on SBS to dentin. SBS to glass-ceramic revealed a positive influence of temperature for TEC 25–68 °C (p = 0.015. TEC showed higher values than V and FSXT (p < 0.001. IFT values increased with the preheating temperature. A significant difference could be observed in every RC group between 25 and 68 °C (p < 0.001.

  12. Effect of pre-heating on the viscosity and microhardness of a resin composite.

    LENUS (Irish Health Repository)

    Lucey, S

    2010-04-01

    The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n = 15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0.001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n = 15) was 68.6 (2.3) for the top surface and 68.7 (1.8) for the bottom surface measured at 24 h post curing (specimen thickness = 1.5 mm). The corresponding values for the room temperature group were 60.6 (1.4) and 59.0 (3.5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0.001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

  13. Efficiency of the pre-heater against flow rate on primary the beta test loop

    International Nuclear Information System (INIS)

    Edy Sumarno; Kiswanta; Bambang Heru; Ainur R; Joko P

    2013-01-01

    Calculation of efficiency of the pre-heater has been carried out against the flow rate on primary the BETA Test Loop. BETA test loop (UUB) is a facilities of experiments to study the thermal hydraulic phenomenon, especially for thermal hydraulic post-LOCA (Lost of Coolant Accident). Sequences removal on the BETA Test Loop contained a pre-heater that serves as a getter heat from the primary side to the secondary side, determination of efficiency is to compare the incoming heat energy with the energy taken out by a secondary fluid. Characterization is intended to determine the performance of a pre-heater, then used as tool for analysis, and as a reference design experiments. Calculation of efficiency methods performed by operating the pre-heater with fluid flow rate variation on the primary side. Calculation of efficiency on the results obtained that the efficiency change with every change of flow rate, the flow rate is 71.26% on 163.50 ml/s and 60.65% on 850.90 ml/s. Efficiency value can be even greater if the pre-heater tank is wrapped with thermal insulation so there is no heat leakage. (author)

  14. Exergy analysis on the irreversibility of rotary air preheater in thermal power plant

    International Nuclear Information System (INIS)

    Wang Hongyue; Zhao Lingling; Zhou Qiangtai; Xu Zhigao; Kim, Hyung Taek

    2008-01-01

    Energy recovery devices can have a substantial impact on process efficiency and their relevance to the problem of conservation of energy resources is generally recognized to be beyond dispute. One type of such a device, which is commonly used in thermal power plants and air conditioning systems, is the rotary air preheater. A major disadvantage of the rotary air preheater is that there is an unavoidable leakage due to carry over and pressure difference. There are gas streams involved in the heat transfer and mixing processes. There are also irreversibilities, or exergy destruction, due to mixing, pressure losses and temperature gradients. Therefore, the purpose of this research paper is based from the second law of thermodynamics, which is to build up the relationship between the efficiency of the thermal power plant and the total process of irreversibility in the rotary air preheater using exergy analysis. For this, the effects of the variation of the principal design parameters on the rotary air preheater efficiency, the exergy efficiency, and the efficiency of the thermal power plant are examined by changing a number of parameters of rotary air preheater. Furthermore, some conclusions are reached and recommendations are made so as to give insight on designing some optimal parameters

  15. Protective garment ventilation system

    Science.gov (United States)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  16. Ventilation rates and health

    DEFF Research Database (Denmark)

    Sundell, Jan; Levin, H; Nazaroff, W W

    2011-01-01

    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...

  17. Ventilation of uranium mines

    International Nuclear Information System (INIS)

    Francois, Y.; Pradel, J.; Zettwoog, P.; Dumas, M.

    1975-01-01

    In the first part of the paper the authors describe the ventilation of French mines in terms of the primary ventilation system, which brings the outside air close to the working places using the overall structure of the mine to form the airways, and the secondary ventilation system, which is for the distribution of the primary air or for the ventilation of the development drifts and blind tunnels. Brief mention is made of the French regulations on the ventilation of mines in general and uranium mines in particular. The authors describe the equipment used and discuss the installed capacities and air flow per man and per working place. The difficulties encountered in properly ventilating various types of working places are mentioned, such as sub-level development drifts, reinforced stopes, and storage chambers with an artificial crown. The second part of the paper is devoted to computer calculations of the primary ventilation system. It is explained why the Commissariat a l'energie atomique has found it necessary to make these calculations. Without restating the mathematical theories underlying the methods employed, the authors demonstrate how simple measuring instruments and a small-size computer can be used to solve the ventilation problems arising in French mines. Emphasis is given to the layout of the ventilation system and to air flow and negative pressure measurements at the base of the mine. The authors show how calculations can be applied to new heading operations, a change in resistance, the replacement or addition of a ventilator, and a new air inlet or outlet. The authors come to the conclusion that since ventilation is at present the most reliable way of avoiding the pollution of mines, a thorough knowledge of the capabilities in this respect can often help improve working conditions. Despite the progress made, however, constant surveillance of the ventilation systems in uranium mines by a separate team with no responsibility for production problems is

  18. Ventilation of uranium mines

    International Nuclear Information System (INIS)

    Francois, Y.; Pradel, J.; Zettwoog, P.; Dumas, M.

    1975-01-01

    In the first part of the paper the authors describe the ventilation of French mines in terms of the primary ventilation system, which brings the outside air close to the working places using the overall structure of the mine to form the airways, and the secondary ventilation system, which is for the distribution of the primary air or for the ventilation of the development drifts and blind tunnels. Brief mention is made of the French regulations on the ventilation of mines in general and uranium mines in particular. The authors describe the equipment used and discuss the installed capacities and air flow per man and per working place. The difficulties encountered in properly ventilating various types of working places are mentioned, such as sublevel development drifts, reinforced stopes, and storage chambers with an artificial crown. The second part of the paper is devoted to computer calculations of the primary ventilation system. It is explained why the Commissariat a l'energie atomique has found it necessary to make these calculations. Without restating the mathematical theories underlying the methods employed, the authors demonstrate how simple measuring instruments and a small-size computer can be used to solve the ventilation problems arising in French mines. Emphasis is given to the layout of the ventilation system and to air flow and negative pressure measurements at the base of the mine. The authors show how calculations can be applied to new heading operations, a change in resistance, the replacement or addition of a ventilator, and a new air inlet or outlet. The authors come to the conclusion that since ventilation is at present the most reliable way of avoiding the pollution of mines, a thorough knowledge of the capabilities in this respect can often help improve working conditions. Despite the progress made, however, constant surveillance of the ventilation systems in uranium mines by a separate team with no responsibility for production problems is

  19. Design Principles for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system -Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and - principles are discussed and illustrated by four building examples....

  20. Natural Ventilation in Atria

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Hendriksen, Ole Juhl

    This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions.......This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions....

  1. 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%.

  2. Emerging large-scale solar heating applications

    International Nuclear Information System (INIS)

    Wong, W.P.; McClung, J.L.

    2009-01-01

    Currently the market for solar heating applications in Canada is dominated by outdoor swimming pool heating, make-up air pre-heating and domestic water heating in homes, commercial and institutional buildings. All of these involve relatively small systems, except for a few air pre-heating systems on very large buildings. Together these applications make up well over 90% of the solar thermal collectors installed in Canada during 2007. These three applications, along with the recent re-emergence of large-scale concentrated solar thermal for generating electricity, also dominate the world markets. This paper examines some emerging markets for large scale solar heating applications, with a focus on the Canadian climate and market. (author)

  3. Emerging large-scale solar heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Wong, W.P.; McClung, J.L. [Science Applications International Corporation (SAIC Canada), Ottawa, Ontario (Canada)

    2009-07-01

    Currently the market for solar heating applications in Canada is dominated by outdoor swimming pool heating, make-up air pre-heating and domestic water heating in homes, commercial and institutional buildings. All of these involve relatively small systems, except for a few air pre-heating systems on very large buildings. Together these applications make up well over 90% of the solar thermal collectors installed in Canada during 2007. These three applications, along with the recent re-emergence of large-scale concentrated solar thermal for generating electricity, also dominate the world markets. This paper examines some emerging markets for large scale solar heating applications, with a focus on the Canadian climate and market. (author)

  4. Effects of preheated combustion air on laminar coflow diffusion flames under normal and microgravity conditions

    Science.gov (United States)

    Ghaderi Yeganeh, Mohammad

    Global energy consumption has been increasing around the world, owing to the rapid growth of industrialization and improvements in the standard of living. As a result, more carbon dioxide and nitrogen oxide are being released into the environment. Therefore, techniques for achieving combustion at reduced carbon dioxide and nitric oxide emission levels have drawn increased attention. Combustion with a highly preheated air and low-oxygen concentration has been shown to provide significant energy savings, reduce pollution and equipment size, and uniform thermal characteristics within the combustion chamber. However, the fundamental understanding of this technique is limited. The motivation of the present study is to identify the effects of preheated combustion air on laminar coflow diffusion flames. Combustion characteristics of laminar coflow diffusion flames are evaluated for the effects of preheated combustion air temperature under normal and low-gravity conditions. Experimental measurements are conducted using direct flame photography, particle image velocimetry (PIV) and optical emission spectroscopy diagnostics. Laminar coflow diffusion flames are examined under four experimental conditions: normal-temperature/normal-gravity (case I), preheated-temperature/normal gravity (case II), normal-temperature/low-gravity (case III), and preheated-temperature/low-gravity (case IV). Comparisons between these four cases yield significant insights. In our studies, increasing the combustion air temperature by 400 K (from 300 K to 700 K), causes a 37.1% reduction in the flame length and about a 25% increase in peak flame temperature. The results also show that a 400 K increase in the preheated air temperature increases CH concentration of the flame by about 83.3% (CH is a marker for the rate of chemical reaction), and also increases the C2 concentration by about 60% (C2 is a marker for the soot precursor). It can therefore be concluded that preheating the combustion air

  5. EFFECT OF PRE-HEAT TREATMENT ON MECHANICAL PROPERTIES OF Ti-6Al-4V WELDS

    Directory of Open Access Journals (Sweden)

    Gnofam Jacques TCHEIN

    2016-11-01

    Full Text Available The work presented here is related to the optimization of the Friction Stir Welding (FSW process. The objective is to study the influence of some parameters used in the production of welded joints by FSW. The most important parameters are the welding speed and the rotational speed of the tool. The effect of pre-heat treatment on the plates to be welded is also studied by the design of experimental methods. These pre-heat treatments result not only in a change of mechanical properties of plates to be welded, but also of their microstructure. The experiments were performed following a 16 lines fractional Taguchi table.

  6. Styret naturlig ventilation

    DEFF Research Database (Denmark)

    Morsing, S.; Strøm, J.S.

    Publikationen præsenterer et generelt dimensioneringsgrundlag for naturlig ventilation i husdyrstalde. Det er kontrolleret ved forsøg i slagtesvinestalde, hvor det ligeledes er undersøgt hvilken temperaturstabilitet, der kan opnås ved naturlig ventilation, samt produktions- og adfærdsmæssige...

  7. 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.

  8. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per; Nielsen, Peter V.

    2014-01-01

    As a novel air distribution system, diffuse ceiling ventilation combines the suspended acoustic ceiling with ventilation supply. Due to the low-impulse supply from the large ceiling area, the system does not generate draught when supplying cold air. However, heat sources play an important role...

  9. Pulmonary perfusion ''without ventilation''

    International Nuclear Information System (INIS)

    Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

    1983-01-01

    An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

  10. Realtime mine ventilation simulation

    International Nuclear Information System (INIS)

    McDaniel, K.H.

    1997-01-01

    This paper describes the development of a Windows based, interactive mine ventilation simulation software program at the Waste Isolation Pilot Plant (WIPP). To enhance the operation of the underground ventilation system, Westinghouse Electric Corporation developed the program called WIPPVENT. While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC and uses the same subroutine to calculate airflow distributions, the user interface has been completely rewritten as a Windows application with screen graphics. WIPPVENT is designed to interact with WIPP ventilation monitoring systems through the sitewise Central monitoring System. Data can be continuously collected from the Underground Ventilation Remote Monitoring and Control System (e.g., air quantity and differential pressure) and the Mine Weather Stations (psychrometric data). Furthermore, WIPPVENT incorporates regulator characteristic curves specific to the site. The program utilizes this data to create and continuously update a REAL-TIME ventilation model. This paper discusses the design, key features, and interactive capabilities of WIPPVENT

  11. Influence of Powder Bed Preheating on Microstructure and Mechanical Properties of H13 Tool Steel SLM Parts

    Science.gov (United States)

    Mertens, R.; Vrancken, B.; Holmstock, N.; Kinds, Y.; Kruth, J.-P.; Van Humbeeck, J.

    Powder bed preheating is a promising development in selective laser melting (SLM), mainly applied to avoid large thermal stresses in the material. This study analyses the effect of in-process preheating on microstructure, mechanical properties and residual stresses during SLM of H13 tool steel. Sample parts are produced without any preheating and are compared to the corresponding parts made with preheating at 100°, 200°, 300°, and 400°C. Interestingly, internal stresses at the top surface of the parts evolve from compressive (-324MPa) without preheating to tensile stresses (371MPa) with preheating at 400°C. Nevertheless, application of powder bed preheating results in a more homogeneous microstructure with better mechanical properties compared to H13 SLM parts produced without preheating. The fine bainitic microstructure leads to hardness values of 650-700Hv and ultimate tensile strength of 1965MPa, which are comparable to or even better than those of conventionally made and heat treated H13 tool steel.

  12. Area 3, SRC-II coal slurry preheater studies report for the technical data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    This report reviews the raw data gathered from the Preheater B test runs at Ft. Lewis, and also the Preheater B results presented in the Solvent Refined Coal (SRC) Process Final Report, Volumes 1 and 2 of Slurry Preheater Design, SRC-II Process and the Ft. Lewis Slurry Preheater Data Analysis, 1 1/2 Inch Coil by Gulf Science and Technology Corporation of Pittsburgh, Pennsylvania. attempts were made to correlate several variables not previously considered with slurry viscosity and thermal conductivity. Only partial success was realized. However, in the process of attempting to correlate these variables an understanding of why some variables could not be correlated was achieved. An attempt was also made, using multiple linear regression, to correlate coal slurry viscosity and thermal conductivity with several independent variables among which were temperature, coal concentration, total solids, coal type, slurry residence time, shear rate, and unit size. The final correlations included some, but not all, of these independent variables. This report is not a stand alone document and should be considered a supplement to work already done. It should be read in conjunction with the reports referenced above.

  13. Experimental Investigation of the Effects of Concrete Alkalinity on Tensile Properties of Preheated Structural GFRP Rebar

    Directory of Open Access Journals (Sweden)

    Hwasung Roh

    2017-01-01

    Full Text Available The combined effects of preexposure to high temperature and alkalinity on the tensile performance of structural GFRP reinforcing bars are experimentally investigated. A total of 105 GFRP bar specimens are preexposed to high temperature between 120°C and 200°C and then immersed into pH of 12.6 alkaline solution for 100, 300, and 660 days. From the test results, the elastic modulus obtained at 300 immersion days is almost the same as those of 660 immersion days. For all alkali immersion days considered in the test, the preheated specimens provide slightly lower elastic modulus than the unpreheated specimens, showing only 8% maximum difference. The tensile strength decreases for all testing cases as the increase of the alkaline immersing time, regardless of the prehearing levels. The tensile strength of the preheated specimens is about 90% of the unpreheated specimen for 300 alkali immersion days. However, after 300 alkali immersion days the tensile strengths are almost identical to each other. Such results indicate that the tensile strength and elastic modulus of the structural GFRP reinforcing bars are closely related to alkali immersion days, not much related to the preheating levels. The specimens show a typical tensile failure around the preheated location.

  14. Preheating to around 100°C under endcap blocks before welding at KHI.

    CERN Multimedia

    Loveless, D

    2000-01-01

    The 600mm thick sector blocks of the CMS endcaps are made from three layers of 200mm plates welded together. During the manufacture at KHI, the blocks are preheated to around 100°C to prevent cracks in the welds.

  15. Enhanced preheating after multi-field inflation: on the importance of being special

    International Nuclear Information System (INIS)

    Battefeld, Thorsten; Eggemeier, Alexander; Giblin, John T. Jr.

    2012-01-01

    We discuss preheating after multi-field inflation in the presence of several preheat matter fields that become light in the vicinity of (but not at) the inflatons' VEV, at distinct extra-species-points (ESP); this setup is motivated by inflationary models that include particle production during inflation, e.g. trapped inflation, grazing ESP encounters or modulated trapping, among others. While de-phasing of inflatons tends to suppress parametric resonance, we find two new effects leading to efficient preheating: particle production during the first in-fall (efficient if many preheat matter fields are present) and a subsequent (narrow) resonance phase (efficient if an ESP happens to be at one of several distinct distances from the inflatons' VEV). Particles produced during the first in-fall are comprised of many species with low occupation number, while the latter are made up of a few species with high occupation number. We provide analytic descriptions of both phases in the absence of back-reaction, which we test numerically. We further perform lattice simulations to investigate the effects of back-reaction. We find resonances to be robust and the most likely cause of inflaton decay in multi-field trapped inflation if ESP distributions are dense

  16. Effect of air preheat temperature on the MILD combustion of syngas

    International Nuclear Information System (INIS)

    Huang, Mingming; Zhang, Zhedian; Shao, Weiwei; Xiong, Yan; Liu, Yan; Lei, Fulin; Xiao, Yunhan

    2014-01-01

    Highlights: • MILD combustion is achieved with reaction zone covering the entire combustion chamber. • Critical equivalence ratio for the occurrence of MILD combustion is identified. • MILD regime can be established for syngas fuel under air preheating conditions. - Abstract: The effect of air preheat temperature on MILD (Moderate or Intense Low-oxygen Dilution) combustion of coal-derived syngas was examined in parallel jet forward flow combustor. The results were presented on flow field using numerical simulations and on global flame signatures, OH ∗ radicals distribution and exhaust emissions using experiments. The discrete and high speed air/fuel injections into the combustor is necessary for the establishment of MILD conditions, because they cause strong gas recirculation and form large mixing region between the air and fuel jets. The critical equivalence ratio above which MILD combustion occurred was identified. The MILD regime was established for syngas fuel under air preheating conditions with lean operational limit and suppressed NO x and CO emissions. In the MILD combustion regime, the air preheating resulted in higher NO x but lower CO emissions, while the increase of equivalence ratio led to the increase of NO x and the decrease of CO emissions

  17. Effect of pre-heating on the thermal decomposition kinetics of cotton

    Science.gov (United States)

    The effect of pre-heating at low temperatures (160-280°C) on the thermal decomposition kinetics of scoured cotton fabrics was investigated by thermogravimetric analysis under nonisothermal conditions. Isoconversional methods were used to calculate the activation energies for the pyrolysis after one-...

  18. Enhanced preheating after multi-field inflation: on the importance of being special

    Energy Technology Data Exchange (ETDEWEB)

    Battefeld, Thorsten; Eggemeier, Alexander [Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, D-37077 Goettingen (Germany); Giblin, John T. Jr., E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: a.eggemeier@stud.uni-goettingen.de, E-mail: giblinj@kenyon.edu [Department of Physics, Kenyon College, Gambier, OH 43022 (United States)

    2012-11-01

    We discuss preheating after multi-field inflation in the presence of several preheat matter fields that become light in the vicinity of (but not at) the inflatons' VEV, at distinct extra-species-points (ESP); this setup is motivated by inflationary models that include particle production during inflation, e.g. trapped inflation, grazing ESP encounters or modulated trapping, among others. While de-phasing of inflatons tends to suppress parametric resonance, we find two new effects leading to efficient preheating: particle production during the first in-fall (efficient if many preheat matter fields are present) and a subsequent (narrow) resonance phase (efficient if an ESP happens to be at one of several distinct distances from the inflatons' VEV). Particles produced during the first in-fall are comprised of many species with low occupation number, while the latter are made up of a few species with high occupation number. We provide analytic descriptions of both phases in the absence of back-reaction, which we test numerically. We further perform lattice simulations to investigate the effects of back-reaction. We find resonances to be robust and the most likely cause of inflaton decay in multi-field trapped inflation if ESP distributions are dense.

  19. Symbiotic potential: the integration of preheating and dry cooling in cokemaking

    Energy Technology Data Exchange (ETDEWEB)

    Barker, J E

    1978-06-01

    In the USSR and Japan, heat recovered from the dry cooling of coke is used to raise steam for power generation or process use. This heat could be used to dry and preheat coal to improve both coke quality and oven productivity.

  20. Ventilating Air-Conditioner

    Science.gov (United States)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  1. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    OpenAIRE

    Sherman, Max H.

    2011-01-01

    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 outd...

  2. 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...

  3. 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.

  4. What Is a Ventilator?

    Science.gov (United States)

    ... who are on ventilators for shorter periods. The advantage of this tube is that it can be ... other disease or condition. VAP is treated with antibiotics. You may need special antibiotics if the VAP ...

  5. 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

  6. Uranium mine ventilation

    International Nuclear Information System (INIS)

    Katam, K.; Sudarsono

    1982-01-01

    Uranium mine ventilation system aimed basically to control and decreasing the air radioactivity in mine caused by the radon emanating from uranium ore. The control and decreasing the air ''age'' in mine, with adding the air consumption volume, increasing the air rate consumption, closing the mine-out area; using closed drainage system. Air consumption should be 60m 3 /minute for each 9m 2 uranium ore surfaces with ventilation rate of 15m/minute. (author)

  7. Fire, safety and ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, D.

    1999-02-01

    Correct ventilation in tunnel environments is vital for the comfort and safety of the people passing through. This article gives details of products from several manufacturers of safety rescue and fire fighting equipment, fire and fume detection equipment, special fire resistant materials, fire resistant hydraulic oils and fire dampers, and ventilation systems. Company addresses and fax numbers are supplied. 4 refs., 5 tabs., 10 photos.

  8. Reproducibility of LiF:Mg, Cup thermoluminescent dosimeter on kilo voltage and megavoltage photon beam using different preheat rate:A glow curve study

    International Nuclear Information System (INIS)

    Mohd Fahmi Mohd Yusof; Robert, T.S.B.; Puteri Norkhatijah Abdul Hamid; Nor Shazleen Abdul Shukor; Mohd Sazarman Mohd Salleh

    2013-01-01

    Full-text: Post-irradiation annealing or preheat of the LiF based TLD prior readout is commonly practiced for routine dosimetry to eliminate low temperature glow peaks. The aim of this study is to determine the effect of different preheating rate technique prior readout on the reproducibility and glow curve structure of LiF:Mg, Cu, P or TLD-1OOH exposed to low (109kVp) energy and high energy (6MV) photon beam. TLD chips were read after 24 hours of irradiation with three different preheat techniques; no preheat, low preheat rate (100 degree Celsius/ 10 minutes) and high preheat rate (135 degree Celsius/ 10 seconds) and reproducibility of TL signals were assessed in term of Standard Deviation (SD) and glow curve peaks. The high preheat rate technique was the most reproducible method for low energy photon with 1.05 % of mean reproducibility followed by low preheat rate (1.16 %) and no-preheat (1.33 %) techniques. The high preheat rate techniques was also the most reproducible method for high energy photon with 0.767 % of mean reproducibility as compared to low preheat rate (1.281 %). However the high preheat technique record highest TL signal lost with 10.35 % and 6.04 % for 24 and 72 hours of delayed TLD readout with respectively compared to 9.27 % and 4.51 % for 24 and 72 hours by low preheat rate. The low preheat was found to be optimal to eliminate low peaks (peak 1 and 2) but enable to remove peak 3 as it was shifted up word to combine with the main peak 4 of TL glow peak. It can be concluded that the reproducibility and structure of glow curve was strongly influenced by preheat technique prior readout. (author)

  9. Demand Controlled Ventilation in a Combined Ventilation and Radiator System

    OpenAIRE

    Hesaraki, Arefeh; Holmberg, Sture

    2013-01-01

    With growing concerns for efficient and sustainable energy treatment in buildings there is a need for balanced and intelligent ventilation solutions. This paper presents a strategy for demand controlled ventilation with ventilation radiators, a combined heating and ventilation system. The ventilation rate was decreased from normal requirements (per floor area) of 0.375 l·s-1·m-2 to 0.100 l·s-1·m-2 when the residence building was un-occupied. The energy saving potential due to decreased ventil...

  10. Clinical challenges in mechanical ventilation.

    Science.gov (United States)

    Goligher, Ewan C; Ferguson, Niall D; Brochard, Laurent J

    2016-04-30

    Mechanical ventilation supports gas exchange and alleviates the work of breathing when the respiratory muscles are overwhelmed by an acute pulmonary or systemic insult. Although mechanical ventilation is not generally considered a treatment for acute respiratory failure per se, ventilator management warrants close attention because inappropriate ventilation can result in injury to the lungs or respiratory muscles and worsen morbidity and mortality. Key clinical challenges include averting intubation in patients with respiratory failure with non-invasive techniques for respiratory support; delivering lung-protective ventilation to prevent ventilator-induced lung injury; maintaining adequate gas exchange in severely hypoxaemic patients; avoiding the development of ventilator-induced diaphragm dysfunction; and diagnosing and treating the many pathophysiological mechanisms that impair liberation from mechanical ventilation. Personalisation of mechanical ventilation based on individual physiological characteristics and responses to therapy can further improve outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. The Solar Dynamic Buffer Zone (SDBZ) curtain wall: Validation and design of a solar air collector curtain wall

    Science.gov (United States)

    Richman, Russell Corey

    Given the increases in both the environmental and economic costs of energy, there is a need to design and building more sustainable and low-energy building systems now. Curtain wall assemblies show great promise---the spandrel panels within them can be natural solar collectors. By using a Solar Dynamic Buffer Zone (SDBZ) in the spandrel cavity, solar energy can be efficiently gathered using the movement of air. There is a need for a numerical model capable of predicting performance of an SDBZ Curtain Wall system. This research designed, constructed and quantified a prototype SDBZ curtain wall system through by experimental testing in a laboratory environment. The laboratory experiments focussed on three main variables: air flow through the system, incoming radiation and collector surface type. Results from the experimental testing were used to validate a one-dimensional numerical model of the prototype. Results from this research show a SDBZ curtain wall system as an effective means of reducing building heating energy consumption through the preheating of incoming exterior ventilation air during the heating season in cold climates. The numerical model showed good correlation with experimental results at higher operating flows and at lower flows when using an apparent velocity at the heat transfer boundary layer. A seasonal simulation for Toronto, ON predicted energy savings of 205 kWh/m2 with an average seasonal efficiency of 28%. This is considered in the upper range when compared to other solar air collectors. Given the lack of published literature for similar systems, this research acts to introduce a simple, innovative approach to collect solar energy that would otherwise be lost to the exterior using already existing components within a curtain wall. Specifically, the research has provided: results from experiments and simulation, a first generation numerical model, aspects of design and construction of the SDBZ curtain wall and specific directions for further

  12. Preheating of manure utilizing heat exchanger and flue gas. Forvarmning af gylle ved varmeveksling med roeggas

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J.

    1987-07-15

    It has been shown that preheating of manures in biomass conversion plants to a temperature of 50-60 deg. C, before the anaerobic digestion takes place at a temperature of 35-45 deg. C, results in an increase of methane production. But the method normally involves an increase in energy consumption. The aim of the project was to develope methods of utilizing heat from flue gas emitted from the boiler connected to the plant, with the help of a heat exchanger. The heat thus recovered would be used to preheat the manure. The chosen method was to inject the flue gas directly into the manure mass, following this up with heat exchanging and condensing. In order to mix the flue gas thoroughly into the manure an ejector was used, this was driven by the manure flow. Results were satisfactory. (AB).

  13. A pre-heating method based on sinusoidal alternating current for lithium-ion battery

    Science.gov (United States)

    Fan, Wentao; Sun, Fengchun; Guo, Shanshan

    2018-04-01

    In this paper, a method of low temperature pre-heating of sinusoidal alternating current (SAC) is proposed. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC pre-heating method. a equivalent electric circuit(EEC) model is established to predict the heat generation rate and temperature status, whose parameters are calibrated from the EIS impedance measurements. The effects of current frequency and amplitude on the heating effect are investigated respectively. A multistep temperature-adaptive amplitude strategy is proposed and the cell can be heated from -20°C to 5°C within 509s at 100Hz frequency with this method.

  14. Computational fluid dynamic on the temperature simulation of air preheat effect combustion in propane turbulent flame

    Science.gov (United States)

    Elwina; Yunardi; Bindar, Yazid

    2018-04-01

    this paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modelling of temperature in propane flames with and without air preheat. The study focuses to investigate the effect of air preheat temperature on the temperature of the flame. A standard k-ε model and Eddy Dissipation model are utilized to represent the flow field and combustion of the flame being investigated, respectively. The results of calculations are compared with experimental data of propane flame taken from literature. The results of the study show that a combination of the standard k-ε turbulence model and eddy dissipation model is capable of producing reasonable predictions of temperature, particularly in axial profile of all three flames. Both experimental works and numerical simulation showed that increasing the temperature of the combustion air significantly increases the flame temperature.

  15. Influence of the Previous Preheating Temperature on the Static Coefficient of Friction with Lubrication

    Directory of Open Access Journals (Sweden)

    M. Živković

    2016-12-01

    Full Text Available Experimental investigations static coefficient of friction in lubricated conditions and pre-heating of the sample pin at high temperatures is discussed in this paper. The static coefficient of friction was measured in the sliding steel copper pins per cylinder of polyvinylchloride. Pins are previously heated in a special chamber from room temperature to a temperature of 800 oC with a step of 50 °C. Tribological changes in the surface layer of the pins caused by pre-heating the pins at high temperatures and cooling systems have very significantly influenced the increase in the coefficient of static friction. The results indicate the possibility of improving the friction characteristics of metal materials based on their thermal treatment at elevated temperatures.

  16. Thermodynamic analysis and conceptual design for partial coal gasification air preheating coal-fired combined cycle

    Science.gov (United States)

    Xu, Yue; Wu, Yining; Deng, Shimin; Wei, Shirang

    2004-02-01

    The partial coal gasification air pre-heating coal-fired combined cycle (PGACC) is a cleaning coal power system, which integrates the coal gasification technology, circulating fluidized bed technology, and combined cycle technology. It has high efficiency and simple construction, and is a new selection of the cleaning coal power systems. A thermodynamic analysis of the PGACC is carried out. The effects of coal gasifying rate, pre-heating air temperature, and coal gas temperature on the performances of the power system are studied. In order to repower the power plant rated 100 MW by using the PGACC, a conceptual design is suggested. The computational results show that the PGACC is feasible for modernizing the old steam power plants and building the new cleaning power plants.

  17. Microshear bond strength of preheated silorane- and methacrylate-based composite resins to dentin.

    Science.gov (United States)

    Demirbuga, Sezer; Ucar, Faruk Izzet; Cayabatmaz, Muhammed; Zorba, Yahya Orcun; Cantekin, Kenan; Topçuoğlu, Hüseyin Sinan; Kilinc, Halil Ibrahim

    2016-01-01

    The aim of this study was to investigate the effect of preheating on microshear bond strength (MSBS) of silorane and methacrylate-based composite resins to human dentin. The teeth were randomly divided into three main groups: (1) composite resins were heated upto 68 °C; (2) cooled to 4 °C; and (3) control [room temperature (RT)]. Each group was then randomly subdivided into four subgroups according to adhesive system used [Solobond M (Voco), All Bond SE (Bisco), Clearfil SE Bond (CSE) (Kuraray), Silorane adhesive system (SAS) (3M ESPE)]. Resin composite cylinders were formed (0.9 mm diameter × 0.7 mm length) and MSBS of each specimen was tested. The preheated groups exhibited the highest MSBS (p composite resins may be an alternative way to increase the MSBS of composites on dentin. © Wiley Periodicals, Inc.

  18. Solar Space and Water Heating for Hospital --Charlottesville, Virginia

    Science.gov (United States)

    1982-01-01

    Solar heating system described in an 86-page report consists of 88 single-glazed selectively-coated baseplate collector modules, hot-water coils in air ducts, domestic-hot-water preheat tank, 3,000 Gallon (11,350-1) concrete urethane-insulated storage tank and other components.

  19. Solar-Heated and Cooled Office Building--Columbus, Ohio

    Science.gov (United States)

    1982-01-01

    Final report documents solar-energy system installed in office building to provide space heating, space cooling and domestic hot water. Collectors mounted on roof track Sun and concentrate rays on fluid-circulating tubes. Collected energy is distributed to hot-water-fired absorption chiller and space-heating and domestic-hot-water preheating systems.

  20. Acid skim milk gels: The gelation process as affected by preheated pH

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Vliet, van T.

    2008-01-01

    The effect of preheating milk (10 min 80 [degree sign]C) at pH values from 6.20 to 6.90 on formation of acid skim milk gels was studied by dynamic oscillation measurements. Up to pH 6.65 a higher pH of heating (pHheating) resulted in a higher G'. Since below pH 4.9 the development of

  1. Energetic, Exergetic, and Economic Analysis of MED-TVC Water Desalination Plant with and without Preheating

    Directory of Open Access Journals (Sweden)

    Nuri Eshoul

    2018-03-01

    Full Text Available Desalination is the sole proven technique that can provide the necessary fresh water in arid and semi-arid countries in sufficient quantities and meet the modern needs of a growing world population. Multi effect desalination with thermal vapour compression (MED-TVC is one of most common applications of thermal desalination technologies. The present paper presents a comprehensive thermodynamic model of a 24 million litres per day thermal desalination plant, using specialised software packages. The proposed model was validated against a real data set for a large-scale desalination plant, and showed good agreement. The performance of the MED-TVC unit was investigated using different loads, entrained vapour, seawater temperature, salinity and number of effects in two configurations. The first configuration was the MED-TVC unit without preheating system, and the second integrated the MED-TVC unit with a preheating system. The study confirmed that the thermo-compressor and its effects are the main sources of exergy destruction in these desalination plants, at about 40% and 35% respectively. The desalination plant performance with preheating mode performs well due to high feed water temperature leading to the production of more distillate water. The seawater salinity was proportional to the fuel exergy and minimum separation work. High seawater salinity results in high exergy efficiency, which is not the case with membrane technology. The plant performance of the proposed system was enhanced by using a large number of effects due to greater utilisation of energy input and higher generation level. From an economic perspective, both indicators show that using a preheating system is more economically attractive.

  2. Resistive vs. total power depositions by Alfven modes in pre-heated low aspect ratio tokamaks

    International Nuclear Information System (INIS)

    Cuperman, S.; Bruma, C.; Komoshvili, K.

    2004-01-01

    The power deposition of fast waves launched by a LFS located antenna in a pre-heated, strongly non-uniform low aspect ratio tokamak (START) is investigated. The rigorous computational results indicate a total power deposition by far larger than that predicted for Alfven continuum eigenmodes in cylindrical plasmas. For toroidal wave numbers |N| > 1, the resistive and total power depositions are almost equal. (author)

  3. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite

    Directory of Open Access Journals (Sweden)

    Theobaldo JD

    2017-05-01

    Full Text Available Jéssica Dias Theobaldo,1 Flávio Henrique Baggio Aguiar,1 Núbia Inocencya Pavesi Pini,2 Débora Alves Nunes Leite Lima,1 Priscila Christiane Suzy Liporoni,3 Anderson Catelan3 1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, 2Ingá University Center, Maringá, 3Departament of Dentistry, University of Taubaté, Taubaté, Brazil Objective: The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC, microhardness (KHN, plasticization (P, and depth of polymerization (DP of a bulk fill composite.Methods: Forty disc-shaped samples (n = 5 of a bulk fill composite were prepared (5 × 4 mm thick and randomly divided into 4 groups according to light-curing unit (quartz–tungsten–halogen [QTH] or light-emitting diode [LED] and preheating temperature (23 or 54 °C. A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey’s test (α = 0.05.Results: Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill.Conclusion: Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated. Keywords: composite resins, physicochemical phenomena, polymerization, hardness, heating

  4. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  5. Solar project description for Helio-Thermics, Inc., lot 6 single family residence; Greenville, South Carolina

    Science.gov (United States)

    Moore, D.

    1981-03-01

    An instrumented single family residence in Greenville, South Carolina, has approximately 1086 square feet on conditioned space. Solar energy is used for space heating the home and preheating domestic and water (DHW). Solar energy enters the attic through a 416 square foot aperture which is double glazed with corrugated, translucent, fiberglass reinforced, acrylic panels. Warm air accumulates in the peak of the attic roof and circulates through the conditioned space or through storage by an air handler. Solar energy is stored in an 870 cubic foot storage bin containing 85,460 pounds of crushed rock located under the house. cold water is preheated in the attic by thermosiphoning water from the 80 gallon preheat tank through a manifold system of copper tubes. These tubes are attached to black sheet metal plates. Preheated city water is stored in the preheat tank and supplied, on demand, to a conventional 80 gallon DHW tank. When solar energy is insufficient to satisfy the space heating load, a water to air heat exchanger in the hot air supply duct provides auxiliary energy for space heating. A gas fired water heater provides auxiliary energy for the water to air heat exchanger and the DHW.

  6. Formation of toroidal pre-heat plasma without residual magnetic field for high-beta pinch experiments

    International Nuclear Information System (INIS)

    Ikeda, Nagayasu; Tamaru, Ken; Nagata, Akiyoshi.

    1979-01-01

    Formation of toroidal pre-heat plasma was studied. The pre-heat plasma without residual magnetic field was made by chopping the current for pre-heat, A small toroidal-pinch system was used for the experiment. The magnetic field was measured with a magnetic probe. One turn loop was used for the measurement of the toroidal one-turn electric field. A pair of Rogoski coil was used for the measurement of plasma current. The dependence of residual magnetic field on chopping time was measured. By fast chopping of the primary current in the pre-heating circuit, the poloidal magnetic field was reduced to several percent within 5 microsecond. After chopping, no instability was observed in the principal discharge plasma produced within several microsecond. As the conclusion, it can be said that the control of residual field can be made by current chopping. (Kato, T.)

  7. Ventilation of radioactive enclosures

    International Nuclear Information System (INIS)

    Caminade, F.; Laurent, H.

    1957-01-01

    Mechanical, physical and chemical manipulations on radioactive products must be carried out in properly ventilated enclosed places. The air extracted can only be discharged into the atmosphere after a correct filtration. The power of the ventilation systems is a function of the dimensions and purpose of the enclosure? The choice of types of filter is determined by the physical state and chemical nature of the radioactive materials to be manipulated. This study deals with the individual equipment of small installations: glove boxes, manipulation boxes with outside control and, if necessary, production chambers (maximum useful volume: 5 m 3 ). The performances of three types of 'ventilators', and the modifications provided by the addition of filters, are measured and compared. (author) [fr

  8. Mechanical ventilation strategies.

    Science.gov (United States)

    Keszler, Martin

    2017-08-01

    Although only a small proportion of full term and late preterm infants require invasive respiratory support, they are not immune from ventilator-associated lung injury. The process of lung damage from mechanical ventilation is multifactorial and cannot be linked to any single variable. Atelectrauma and volutrauma have been identified as the most important and potentially preventable elements of lung injury. Respiratory support strategies for full term and late preterm infants have not been as thoroughly studied as those for preterm infants; consequently, a strong evidence base on which to make recommendations is lacking. The choice of modalities of support and ventilation strategies should be guided by the specific underlying pathophysiologic considerations and the ventilatory approach must be individualized for each patient based on the predominant pathophysiology at the time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. [Ventilator associated pneumonia].

    Science.gov (United States)

    Bellani, S; Nesci, M; Celotto, S; Lampati, L; Lucchini, A

    2003-04-01

    Ventilator associated pneumonia (VAP) is a nosocomial lower respiratory tract infection that ensues in critically ill patients undergoing mechanical ventilation. The reported incidence of VAP varies between 9% and 68% with a mortality ranging between 33% and 71%. Two key factors are implicated in the pathogenesis of VAP: bacterial colonization of the upper digestive-respiratory tract and aspiration of oral secretions into the trachea. Preventive measurements are advocated to reduce the incidence of VAP, such as selective decontamination of the digestive tract (SDD), supraglottic aspiration and positioning. Prompt recognition and treatment of established VAP has also been demostrated to affect outcome. Therefore, the knowledge of risk factors associated with the development of VAP and the implementation of strategies to prevent, diagnose and treat VAP are mainstems in the nursing of mechanically ventilated patients.

  10. 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...

  11. Auxiliary mine ventilation manual

    International Nuclear Information System (INIS)

    Workplace Safety North

    2010-01-01

    An adequate ventilation system is needed for air quality and handling in a mine and is comprised of many different pieces of equipment for removing contaminated air and supplying fresh air and thereby provide a satisfactory working environment. This manual highlights auxiliary ventilation systems made up of small fans, ducts, tubes, air movers, deflectors and additional air flow controls which distribute fresh air delivered by the primary system to all areas. A review of auxiliary ventilation is provided. Design, operation and management issues are discussed and guidelines are furnished. This manual is limited to underground hard rock operations and does not address directly other, specific auxiliary systems, either in underground coal mines or uranium mines.

  12. Auxiliary mine ventilation manual

    Energy Technology Data Exchange (ETDEWEB)

    Workplace Safety North

    2010-07-01

    An adequate ventilation system is needed for air quality and handling in a mine and is comprised of many different pieces of equipment for removing contaminated air and supplying fresh air and thereby provide a satisfactory working environment. This manual highlights auxiliary ventilation systems made up of small fans, ducts, tubes, air movers, deflectors and additional air flow controls which distribute fresh air delivered by the primary system to all areas. A review of auxiliary ventilation is provided. Design, operation and management issues are discussed and guidelines are furnished. This manual is limited to underground hard rock operations and does not address directly other, specific auxiliary systems, either in underground coal mines or uranium mines.

  13. Solar renovation demonstration projects

    Energy Technology Data Exchange (ETDEWEB)

    Bruun Joergensen, O [ed.

    1998-10-01

    In the framework of the IEA SHC Programme, a Task on building renovation was initiated, `Task 20, Solar Energy in Building Renovation`. In a part of the task, Subtask C `Design of Solar Renovation Projects`, different solar renovation demonstration projects were developed. The objective of Subtask C was to demonstrate the application of advanced solar renovation concepts on real buildings. This report documents 16 different solar renovation demonstration projects including the design processes of the projects. The projects include the renovation of houses, schools, laboratories, and factories. Several solar techniques were used: building integrated solar collectors, glazed balconies, ventilated solar walls, transparent insulation, second skin facades, daylight elements and photovoltaic systems. These techniques are used in several simple as well as more complex system designs. (au)

  14. Phase change material thermal storage for biofuel preheating in micro trigeneration application: A numerical study

    International Nuclear Information System (INIS)

    Wu, Dawei; Chen, Junlong; Roskilly, Anthony P.

    2015-01-01

    Highlights: • Engine exhaust heat driven phase change material thermal storage. • Fuel preheating for direct use of straight plant oil on diesel engine. • CFD aided design of the phase change material thermal storage. • Melting and solidification model considering natural convection. - Abstract: A biofuel micro trigeneration prototype has been developed to utilise local energy crop oils as fuel in rural areas and developing countries. Straight plant oils (SPOs) only leave behind very little carbon footprint during its simply production process compared to commercial biodiesels in refineries, but the high viscosity of SPOs causes difficulties at engine cold starts, which further results in poor fuel atomisation, compromised engine performance and fast engine deterioration. In this study, a phase change material (PCM) thermal storage is designed to recover and store engine exhaust heat to preheat SPOs at cold starts. High temperature commercial paraffin is selected as the PCM to meet the optimal preheating temperature range of 70–90 °C, in terms of the SPO property study. A numerical model of the PCM thermal storage is developed and validated by references. The PCM melting and solidification processes with the consideration of natural convection in liquid zone are simulated in ANSYS-FLUENT to verify the feasibility of the PCM thermal storage as a part of the self-contained biofuel micro trigeneration prototype

  15. Experimental investigation of laminar LPG-H{sub 2} jet diffusion flame with preheated reactants

    Energy Technology Data Exchange (ETDEWEB)

    D.P. Mishra; P. Kumar [Indian Institute of Technology, Kanpur (India). Combustion Laboratory, Department of Aerospace Engineering

    2008-10-15

    This paper presents an experimental investigation of the effect of H{sub 2} addition on flame length, soot free length fraction (SFLF), flame radiant fraction, gas temperature and emission level in LPG-H{sub 2} composite fuel jet diffusion flame for two preheated cases namely, (i) preheated air and (ii) preheated air and fuel. Results show that the H{sub 2} addition leads to a reduction in flame length which may be caused due to an increased gas temperature. Besides this, the flame length is also observed to be reduced with increasing reactants temperature. The soot free length fraction (SFLF) increases as H{sub 2} is added to fuel stream. This might have been caused by decrease in the C/H ratio in the flame and is favorable to attenuate PAH formation rate. Interestingly, the SFLF is observed to be reduced with increasing reactants temperature that may be due to reduction in induction period of soot formation caused by enhanced flame temperature. Moreover, the decreased radiant heat fraction with hydrogen addition is pertinent with the reduction in soot concentration level. The reduction in NOx emission level with H{sub 2} addition to the fuel stream is also observed. On the contrary, NOx emission level is found to be enhanced significantly with reactant temperature that can be attributed to the increase in thermal NOx through Zeldovich mechanism. 31 refs., 4 figs., 2 tabs.

  16. Delayed coking unit preheat train optimization; Otimizacao do preaquecimento das Unidades de Coque

    Energy Technology Data Exchange (ETDEWEB)

    Marins, Edson R; Geraldelli, Washington O; Barros, Francisco C [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    The oil industry has been investing in research and development of new techniques and process improvements with the objective to increase the residual fraction profitability and to fulfill the market demands. The adequacy of the refining scheme has led to the development of bottom of the barrel processes that has the objective to convert heavy fractions into products of higher aggregate value. In this context, the process of Delayed Coking presents a great importance in the production of distillates in the diesel range as well as the processing of heavy residues, mostly in the markets where the fuel oil consumption is being reduced. With the approach to help PETROBRAS decide which route to follow during new designs of Delayed Coking units, this work presents a comparative study of the preheat train performance among the energy recovery to preheat the feed, in contrast with preheating the feed and generating steam, simultaneously. In this study the Pinch Technology methodology was used as a procedure for heat integration with the objective of getting the maximum energy recovery from the process, finding the best trade-off between operational cost and investment cost. The alternative of steam generation aims to provide an appropriate flexibility in Delayed Coking units design and operation. (author)

  17. Liquid-phase synthesis of vertically aligned carbon nanotubes and related nanomaterials on preheated alloy substrates

    Science.gov (United States)

    Yamagiwa, Kiyofumi

    2018-02-01

    Carbon nanotubes (CNTs) and related nanocarbons were selectively synthesized on commercially available alloy substrates by a simple liquid-phase technique. Fe- and Ni-rich stainless-steel (JIS SUS316L and Inconel®600, respectively) and Ni-Cu alloy (Monel®400) substrates were used for the synthesis, and each substrate was preheated in air to promote the self-formation of catalyst nanolayers on the surface. The substrates were resistance heated in ethanol without any addition of catalysts to grow CNTs. The yield of the CNTs effectively increased when the preheating process was employed. Highly aligned CNT arrays grew on the SUS316L substrate, while non-aligned CNTs and distinctive twisted fibers were observed on the other substrates. An Fe oxide layer was selectively formed on the preheated SUS316L substrate promoting the growth of the CNT arrays. Characterizations including cyclic voltammetry for the arrays revealed that the CNTs possess a comparatively defect-rich surface, which is a desirable characteristic for its application such as electrode materials for capacitors.

  18. Pre-HEAT: submillimeter site testing and astronomical spectra from Dome A, Antarctica

    Science.gov (United States)

    Kulesa, C. A.; Walker, C. K.; Schein, M.; Golish, D.; Tothill, N.; Siegel, P.; Weinreb, S.; Jones, G.; Bardin, J.; Jacobs, K.; Martin, C. L.; Storey, J.; Ashley, M.; Lawrence, J.; Luong-Van, D.; Everett, J.; Wang, L.; Feng, L.; Zhu, Z.; Yan, J.; Yang, J.; Zhang, X.-G.; Cui, X.; Yuan, X.; Hu, J.; Xu, Z.; Jiang, Z.; Yang, H.; Li, Y.; Sun, B.; Qin, W.; Shang, Z.

    2008-07-01

    Pre-HEAT is a 20 cm aperture submillimeter-wave telescope with a 660 GHz (450 micron) Schottky diode heterodyne receiver and digital FFT spectrometer for the Plateau Observatory (PLATO) developed by the University of New South Wales. In January 2008 it was deployed to Dome A, the summit of the Antarctic plateau, as part of a scientific traverse led by the Polar Research Institute of China and the Chinese Academy of Sciences. Dome A may be one of the best sites in the world for ground based Terahertz astronomy, based on the exceptionally cold, dry and stable conditions which prevail there. Pre-HEAT is measuring the 450 micron sky opacity at Dome A and mapping the Galactic Plane in the 13CO J=6-5 line, constituting the first submillimeter measurements from Dome A. It is field-testing many of the key technologies for its namesake -- a successor mission called HEAT: the High Elevation Antarctic Terahertz telescope. Exciting prospects for submillimeter astronomy from Dome A and the status of Pre-HEAT will be presented.

  19. Modelling of preheated regenerative chain in Cernavoda NPP using MMS calculation code

    International Nuclear Information System (INIS)

    Bigu, M.; Nita, I.; Prisecaru, I.; Dupleac, D.

    2005-01-01

    Full text: In this work it was studied operation of preheated regenerative chain from NPP Cernavoda. To obtain this analysis coupled analyses of condensate system, water supply system, and drain cooler system were effected. The analysis boundaries are: Upstream: - Steam condensers - Turbine Bleed Steam Downstream: - Steam Generators. The analysis was made in two steps: 1) Getting of hydraulic characteristic of pipe network from steam condensers to steam generators at nominal regime; this step was obtained with hydraulic package called PIPENET. 2) Real thermal hydraulic analyses were done based on hydraulic characteristic of pipe network and supplementary data required for heat transfer calculation in equipment of preheated regenerative chain. Thermal analyses were done using MMS package and refered to normal operating regimes, namely, nominal operating regime required for calibration of calculating model, shutdown regime, start-up regime from zero power hot to nominal power and to abnormal operating regimes, namely, turbine trip, reactor trip and loss of two condensate pumps. The results were compared with already existing analysis and showed the largest differences at interface areas (i.e. 5%). This led us to idea of extending analysis to all secondary circuits in order to reduce the number of boundary conditions which can generate uncertainty in analysis. In this analysis we obtained an advanced model of preheated regenerative chain of secondary circuit in Cernavoda NPP which could be extended up to cover the whole secondary circuit by including the analysis of steam generators, turbine, and steam condenser. (authors)

  20. Modelling of preheated regenerative chain in Cernavoda NPP using MMS calculation code

    International Nuclear Information System (INIS)

    Bigu, M.; Nita, I.; Prisecaru, I.; Dupleac, D.

    2005-01-01

    In this work it was studied operation of preheated regenerative chain from NPP Cernavoda. To obtain this analysis coupled analyses of condensate system, water supply system, and drain cooler system were effected. The analysis boundaries are: Upstream: - Steam condensers - Turbine Bleed Steam Downstream: - Steam Generators. The analysis was made in two steps: 1) Getting of hydraulic characteristic of pipe network from steam condensers to steam generators at nominal regime; this step was obtained with hydraulic package called PIPENET. 2) Real thermal hydraulic analyses were done based on hydraulic characteristic of pipe network and supplementary data required for heat transfer calculation in equipment of preheated regenerative chain. Thermal analyses were done using MMS package and referred to normal operating regimes, namely, nominal operating regime required for calibration of calculating model, shutdown regime, start-up regime from zero power hot to nominal power and to abnormal operating regimes, namely, turbine trip, reactor trip and loss of two condensate pumps. The results were compared with already existing analysis and showed the largest differences at interface areas (i.e. 5%). This led US to idea of extending analysis to all secondary circuits in order to reduce the number of boundary conditions which can generate uncertainty in analysis. In this analysis we obtained an advanced model of preheated regenerative chain of secondary circuit in Cernavoda NPP which could be extended up to cover the whole secondary circuit by including the analysis of steam generators, turbine, and steam condenser. (authors)

  1. Plasma formation and target preheating by prepulse of PW laser light

    Science.gov (United States)

    Sentoku, Yasuhiko; Iwata, Natsumi; Koga, James; Dover, Nicholas; Nishiuchi, Mamiko

    2017-10-01

    An intense short pulse laser with intensity over 1021 W/cm2 has become available, i.e. J-KAREN-P at QST. Although the contrast of the short pulse is improved to be of the order of 10-11, there is an unavoidable prepulse, which has multiple spikes (ps) on top of an exponential profile with intensity greater than 1014 W/cm2 about 50 ps in front of the main pulse. The prepulse preheats the target and also produces tenuous plasmas in front of a target before the main pulse arrives. It is critical to understand such preheating of the target, where the nonlocal heat transport is essential at intensity >1014 W/cm2, since the target condition might totally change before the interaction with the main pulse. Using a hydro code, FLASH, and a collisional particle-in-cell code, PICLS, we study the preplasma formation and target preheating over tens of picoseconds timescale, and discuss the prepulse effects on the main pulse interaction. Work supported by the JSPS KAKENHI under Grant No. JP15K21767.

  2. Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

    International Nuclear Information System (INIS)

    Jolley, R.L.; Begovich, J.M.; Brashear, H.R.

    1983-12-01

    Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be 133 Xe, and 198 Au (on carbonized resin or as an aqueous colloidal suspension) will be used as the slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing

  3. Tekken tests in a steel 'ASTM A 514 GR B' to determine the preheating temperature

    International Nuclear Information System (INIS)

    Quesada, Hector Juan; Zalazar, Monica; Asta, Eduardo Pablo

    2004-01-01

    Cold fissure tests are used to determine the proper preheating temperature in order to prevent fissures during the steel welding process. Tekken tests were carried out on a quenched and tempered high resistance 25.4 mm thick steel (ASTM A514 Gr.B) used in structural applications. The welding was carried out using a FCAW semiautomatic process with gas protection and low hydrogen tubular electrode E110T5-K4. Similar parameters and splicing design were later applied in production. The microstructures of the base material and the welding were determined by optic and electron microscopy. The thermal cycles of the welding were recorded in order to relate the preheating temperature with the cooling time from 800 o C - 500 o C (t 8/5 ) and from 800 o C - 100 o C (tg/1) and the presence or not of fissures. Preheating at 150 o C and t 8/5 greater than 17 s was found to guarantee fissure free welding (CW)

  4. Tekken testing to determine the preheating temperature on ASTM A514 GR B steel

    International Nuclear Information System (INIS)

    Asta, Eduardo; Zalazar, Monica; Quesada, Hector

    2003-01-01

    The cold cracking test methods are used to determine the preheating temperature in order to avoid cracking in steel welding.In this work Tekken tests on high strength quenching and tempering (ASTM A514 GrB) structural steel with a thickness of 25 mm have been made.The welds were done using a FCAW process with gas shielding and basic low hydrogen cored wire E 110T5-K4.The welding parameters and joint design applied in this work are similar to the ones used on site production.The base metal, HAZ and weld metal microstructure have been evaluated by optical and SEM microscopy.Thermal cycles records of each welding have been made to relate preheat temperature with the cooling time on the range of 800-500 degC (t8/5) or 800-100degC (t8/1) and the evidence of crack or no crack condition.Finally, a preheat temperature of 150degC and the cooling time larger than 17 s improve a welding integrity without cracks

  5. Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

    Science.gov (United States)

    1981-01-01

    A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

  6. 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...

  7. Behovstyret ventilation til enfamiliehuse

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Drivsholm, Christian; Hansen, Mads Peter Rudolph

    Muligheden for behovsstyret ventilation i enfamiliehuse er undersøgt. To strategier er afprøvet i praksis: En relativ simpel og billig strategi og en relativ avanceret og dyr strategi. Den simple strategi regulerer luftskiftet ensartet for alle rum mellem et lavt eller højt niveau. Den avancerede...... ventilation efter gældende krav. Desuden kræver den simple regulering kun få sensorer og er således væsentlig billigere og enklere at implementere end den avancerede strategi....

  8. Bench performance of ventilators during simulated paediatric ventilation.

    Science.gov (United States)

    Park, M A J; Freebairn, R C; Gomersall, C D

    2013-05-01

    This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

  9. 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.

  10. Demand controlled ventilation; Behovsstyrt ventilasjon

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Henning Holm

    2006-07-01

    The terms CAV and VAV have been known terms for many years in the ventilation business. The terms are also included in building regulations, but the time is now right to focus on demand controlled ventilation (DCV). The new building regulations and the accompanying energy framework underline the need for a more nuanced thinking when it comes to controlling ventilation systems. Descriptions and further details of the ventilation systems are provided (ml)

  11. Battery life of portable home ventilators: effects of ventilator settings.

    Science.gov (United States)

    Falaize, Line; Leroux, Karl; Prigent, Hélène; Louis, Bruno; Khirani, Sonia; Orlikowski, David; Fauroux, Brigitte; Lofaso, Frédéric

    2014-07-01

    The battery life (BL) of portable home ventilator batteries is reported by manufacturers. The aim of this study was to evaluate the effects of ventilator mode, breathing frequency, PEEP, and leaks on the BL of 5 commercially available portable ventilators. The effects of the ventilator mode (volume controlled-continuous mandatory ventilation [VC-CMV] vs pressure support ventilation [PSV]), PEEP 5 cm H2O, breathing frequency (10, 15, and 20 breaths/min), and leaks during both volume-targeted ventilation and PSV on the BL of 5 ventilators (Elisée 150, Monnal T50, PB560, Vivo 50, and Trilogy 100) were evaluated. Each ventilator was ventilated with a test lung at a tidal volume of 700 ml and an inspiratory time of 1.2 s in the absence of leaks. Switching from PSV to VC-CMV or the addition of PEEP did not significantly change ventilator BL. The increase in breathing frequency from 10 to 20 breaths/min decreased the BL by 18 ± 11% (P = .005). Leaks were associated with an increase in BL during the VC-CMV mode (18 ± 20%, P = .04) but a decrease in BL during the PSV mode (-13 ± 15%, P = .04). The BL of home ventilators depends on the ventilator settings. BL is not affected by the ventilator mode (VC-CMV or PSV) or the addition of PEEP. BL decreases with an increase in breathing frequency and during leaks with a PSV mode, whereas leaks increase the duration of ventilator BL during VC-CMV. Copyright © 2014 by Daedalus Enterprises.

  12. Energy efficient ventilation based on demand humidity control. Demonstration project with 49 apartments in Soenderborg

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The aim of the project is to demonstrate how the overall energy consumption in apartment buildings can be reduced through a combination of: 1) Energy efficient ventilation based on demand humidity control; 2) Energy efficient design of the building shell including passive solar and seasonally flexible sunspaces; 3) Use of low temperature heating system. The 3 blocks in the project, each with 16 apartments, are furnished with 3 different ventilation systems: 1) Standard exhaust system according to building codes; 2) Ventilation system with humidity control. Each room is furnished with an air inlet valve controlled by a processor, which monitors the humidity; 3) Standard ventilation system with heat recovery. (au)

  13. 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...

  14. Ventilator and viral induced inflammation

    NARCIS (Netherlands)

    Hennus, M.P.

    2013-01-01

    This thesis expands current knowledge on ventilator induced lung injury and provides insights on the immunological effects of mechanical ventilation during viral respiratory infections. The experimental studies in the first part of this thesis improve our understanding of how mechanical ventilation

  15. How to Plan Ventilation Systems.

    Science.gov (United States)

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  16. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, P.; Nielsen, Peter Vilhelm

    The main objective of ventilation is to provide good air quality for the occupants. For this purpose the necessary ventilating air change rate must be determined. Within displacement ventilation the estimation is closely related to the air flow rate in the thermal plumes when an air quality based...

  17. The amazing Minivent ventilator

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia is co-published by Medpharm Publications, NISC (Pty) Ltd and Cogent, ... Respiratory rate was obtained by counting the clicking noise ... was appointed as a part-time lecturer to the University of the ... The Minivent became the first of three miniature ventilators that.

  18. Omnidirectional ventilated acoustic barrier

    Science.gov (United States)

    Zhang, Hai-long; Zhu, Yi-fan; Liang, Bin; Yang, Jing; Yang, Jun; Cheng, Jian-chun

    2017-11-01

    As an important problem in acoustics, sound insulation finds applications in a great variety of situations. In the existing schemes, however, there has always been a trade-off between the thinness of sound-insulating devices and their ventilating capabilities, limiting their potentials in the control of low-frequency sound in high ventilation environments. Here, we design and experimentally implement an omnidirectional acoustic barrier with a planar profile, subwavelength thickness ( 0.18 λ ), yet high ventilation. The proposed mechanism is based on the interference between the resonant scattering of discrete states and the background scattering of continuous states which induces a Fano-like asymmetric transmission profile. Benefitting from the binary-structured design of the coiled unit and hollow pipe, it maximally simplifies the design and fabrication while ensuring the ventilation for all the non-resonant units with open tubes. The simulated and measured results agree well, showing the effectiveness of our proposed mechanism to block low frequency sound coming from various directions while allowing 63% of the air flow to pass. We anticipate our design to open routes to design sound insulators and to enable applications in traditionally unattainable cases such as those calling for noise reduction and cooling simultaneously.

  19. Mechanical ventilation of mice

    NARCIS (Netherlands)

    Schwarte, L. A.; Zuurbier, C. J.; Ince, C.

    2000-01-01

    Due to growing interest in murine functional genomics research, there is an increasing need for physiological stable in vivo murine models. Of special importance is support and control of ventilation by artificial respiration, which is difficult to execute as a consequence of the small size of the

  20. Lavt elforbrug til ventilation

    DEFF Research Database (Denmark)

    Jagemar, L.; Bergsøe, Niels Christian

    Rapporten giver gode råd om mulige energibesparelser og praktiske projekteringshensyn, som er forbundet med udformning af energieffektiv ventilation i ikke blot kontorbygninger, men i alle bygninger med komfortventilationsanlæg. I forbindelse med projektering af ventilationsanlæg har interessen...

  1. Understanding mechanical ventilators.

    Science.gov (United States)

    Chatburn, Robert L

    2010-12-01

    The respiratory care academic community has not yet adopted a standardized system for classifying and describing modes of ventilation. As a result, there is enough confusion that patient care, clinician education and even ventilator sales are all put at risk. This article summarizes a ventilator mode taxonomy that has been extensively published over the last 15 years. Specifically, the classification system has three components: a description of the control variables within breath; a description of the sequence of mandatory and spontaneous breaths; and a specification for the targeting scheme. This three-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside, we need only refer to a mode briefly using the first or perhaps first and second components. To distinguish between similar modes and brand names, we would need to include all components. This taxonomy uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing modes of mechanical ventilation are defined in an extensive appendix.

  2. 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...

  3. Hybrid solar central receiver for combined cycle power plant

    Science.gov (United States)

    Bharathan, Desikan; Bohn, Mark S.; Williams, Thomas A.

    1995-01-01

    A hybrid combined cycle power plant including a solar central receiver for receiving solar radiation and converting it to thermal energy. The power plant includes a molten salt heat transfer medium for transferring the thermal energy to an air heater. The air heater uses the thermal energy to preheat the air from the compressor of the gas cycle. The exhaust gases from the gas cycle are directed to a steam turbine for additional energy production.

  4. Solar space and water heating system installed at Charlottesville, Virginia

    Science.gov (United States)

    1980-01-01

    The solar energy system located at David C. Wilson Neuropsychiatric Hospital, Charlottesville, Virginia, is described. The solar energy system consists of 88 single glazed, Sunworks 'Solector' copper base plate collector modules, hot water coils in the hot air ducts, a Domestic Hot Water (DHW) preheat tank, a 3,000 gallon concrete urethane insulated storage tank and other miscellaneous components. Extracts from the site files, specifications, drawings, installation, operation and maintenance instructions are included.

  5. Interaction of regulation and innovation: Solar air heating collectors

    OpenAIRE

    Kramer, K.

    2012-01-01

    Solar Air Heating Collectors have still a very small share of 0.8% of the nominal installed capacity in the solar heating and cooling market (151.7 GWth) [1]. Although constituting a niche market, the potential of those kind of collectors to provide heat for industrial processes, processing food, room heating, air preheating, drying processes or air conditioning could be significant. However, the technical potentials of the various technological solutions are not easy to compare. Such a compa...

  6. Ventilation of nuclear power plants

    International Nuclear Information System (INIS)

    Madoyan, A.A.; Vlasik, V.F.

    1984-01-01

    Foundations and calculation methods of ventilation of rooms with different degree of heat and gas release with the change of operation mode of NPP main equipment, as well as problems of NPP site and adjoining area aerodynamics, have been presented. Systems of air ventilation and conditioning, cooling equipment, are considered. The main points of designing are described and determination of economic efficiency of the ventilation systems are made. Technical characteristics of the ventilators, conditioners, filters and air heaters used, are presented. Organization of adjustment, tests, operation and maintenance of the ventilation systems of NPP with RBMK and WWER-type reactors, is described

  7. Design Procedure for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Tjelflaat, Per Olaf

    Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilises and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation....... Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC....... The first ideas on a design procedure for hybrid ventilation is presented and the different types of design methods, that is needed in different phases of the design process, is discussed....

  8. The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages.

    Science.gov (United States)

    Sadler, D H; Young, O A

    1993-01-01

    Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage. Texture analysis was carried out on formulations which had 20% of meat protein replaced by 20% tendons which were raw or had been preheated to 50, 60, 70, or 80°C. Fracturability decreased by about 40% with raw tendon, but was restored to within 20% of the no-replacement control if the tendon had been preheated. Hardness was approximately doubled by replacement with raw tendon or tendon heated at 50°C. At temperatures higher than that, hardness returned to approximately no-replacement levels. For sensory evaluation (0-25% replacement; preheating at 70°C), sausages were assessed by a 12-member panel for texture, flavour and overall acceptability. All attributes decreased with increasing collagen content, the decrease being less marked with preheated tendon. Thus more connective tissue could be added for the same panel score if the tissue was preheated. Comparison of the texture profile and the panel scores for texture at the same lean replacement level suggested that reduced fracturability was the texture parameter that panellists objected to when heated tendon replaced some of the lean. Other researchers have shown that connective tissue preheated to 100°C before addition in emulsion sausages results in improved yields and better sensory attributes, but the present results show that temperatures as low as 60°C can be effective for beef tendon. Copyright © 1993. Published by Elsevier Ltd.

  9. 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

  10. Feasibility study of utilizing solar furnace technology in steel making industry

    Energy Technology Data Exchange (ETDEWEB)

    Abbaspoursani, K. [The Faculty of Mechanical Engineering, Takestan Islamic Azad University (Iran, Islamic Republic of)], Email: a.abbaspour@tiau.ac.ir; Tofigh, A.A.; Nahang Toudeshki, S.; Hadadian, A. [Department of Energy, Materials and Energy Research Center (Iran, Islamic Republic of)], Email: Ali.A.Tofigh@gmail.com, email: toudeshki@hotmail.com, email: Arash.Hadadian@gmail.com; Farahmandpour, B. [Iranian Fuel Conservation company (Iran, Islamic Republic of)], Email: farahmandpour@gmail.com

    2011-07-01

    In Iran, the casting industry consumes 33.6% of electricity production, and most of this electricity is used in the melting process. Currently, scrap preheating is done using electric arc furnaces and the aim of this study is to assess the feasibility of replacing electric arc furnaces with solar furnaces. The performance of solar furnaces in the Iran Alloy Steel Company under Yazd climate conditions was studied. It was found that the solar irradiation time and solar insulation are sufficient to operate a solar furnace with the capacity to preheat 250 thousand tons per year of scrap to 500 degrees celsius. Results showed that such a furnace would decrease energy consumption by 40 GWh per year and that it would take 5 years to return the investment. This study demonstrated that operating a solar furnace in the Iran Alloy Steel Company under Yazd climate conditions is feasible and would result in economic and environmental benefits.

  11. THE INFLUENCE OF PRE-HEAT TREATMENT ON WHITE CAST IRONS PLASTICITY

    Directory of Open Access Journals (Sweden)

    T. M. Myronova

    2013-11-01

    Full Text Available Purpose. The development of heat treatment modes of white cast irons for structure changes in their eutectic constituent, namely in disturbing the monolithic structure of ledeburite colonies cementite structure and eutectic net continuity. Also the mentioned heat treatment modes are targeted to the eutectic net shift for the most suitable position from the point of plastic deforming. Methodology. The hypoeutectic white cast irons with 2.92…3.35 % carbon content and additionally alloyed by 3.18 % vanadium have been used as the research materials. The mentioned alloys have been pre-heat treated and hot twist tested. Findings. The research results showed that the carbide net breaking by plastic deforming leads to cast irons mechanical properties increasing but has difficulties in implementation due to the white cast irons low plasticity. The influence of different pre-heat treatment modes on structure and plasticity of white hypoeutectic cast irons have been investigated. They include the isotherm soaking under the different temperatures as well as multiply soakings and thermo-cycling. The influence of eutectic level, as well as pre heat treatment modes on different composition white cast irons hot plasticity have been investigated. Originality. It was determined that the heat treatment, which leads to double α→γ recrystallization under 860 – 950 °С and reperlitization under 720-680 °С results in significant increase of plasticity, as well as in un-alloyed and alloyed by vanadium white cast irons. It takes place due to carbide matrix phase separation in ledeburite colonies by new phase boundaries forming especially due to carbide transformations under vanadium alloying. Practical value. The implementation of pre-heat treatment with phase recrystallization resulted in hypoeutectic white cast irons plasticity increasing. The obtained level of cast iron plasticity corresponds to the one of carbide class steels, which ensures the successful

  12. Thermal energy analysis of a lime production process: Rotary kiln, preheater and cooler

    International Nuclear Information System (INIS)

    Shahin, Hamed; Hassanpour, Saeid; Saboonchi, Ahmad

    2016-01-01

    Highlights: • The integrated model for lime production unit which includes cooler, preheater and rotary kiln is developed. • The effect of residence time in each section on efficiency is investigated. • Influence of material feed rate and excess air on specific fuel consumption is analyzed. • The significant effect of particle size on efficiency and specific fuel consumption is shown. - Abstract: In this paper, thermal energy analysis of three zones of a lime production process, which are preheater, rotary kiln and cooler, is performed. In order to perform a proper quantitative estimation, the system was modeled using energy balance equations including coupled heat transfer and chemical reaction mechanisms. A mathematical model was developed, and consequently, the thermal and chemical behavior of limestone was investigated. The model was verified using empirical data. After model confirmation, the variation of Specific Fuel Consumption (SFC) versus production rate was predicted and the optimum condition was determined. Subsequently, fuel consumption was calculated regarding to altered residence time inside each zone of lime production process, for a constant output. Results indicate that increasing the residence time inside each zone of lime production process, will enhance thermal efficiency and saves fuel consumption. Relative enhancement will be the same for different sizes of limestone. It was found that a 10-min increase in material residence time inside the preheater or rotary kiln can reduce fuel consumption by around two percent. Whereas, a 5-min increase in material residence time inside the cooler would be enough to obtain a similar result. Finally, the ratio of air-to-fuel and production rate are changed in such a way that the same product is achieved. The model predicts that lowering excess air from 15% to 10% leads to a 2.5% reduction of Specific Fuel Consumption (SFC).

  13. Minimizing scatter-losses during pre-heat for magneto-inertial fusion targets

    Science.gov (United States)

    Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, Thomas J.; Bliss, David E.; Glinsky, Michael E.; Gomez, Matthew R.; Harding, Eric; Hansen, Stephanie B.; Jennings, Christopher; Kimmel, Mark W.; Knapp, Patrick; Lewis, Sean M.; Peterson, Kyle; Schollmeier, Marius; Schwarz, Jens; Shores, Jonathon E.; Slutz, Stephen A.; Sinars, Daniel B.; Smith, Ian C.; Speas, C. Shane; Vesey, Roger A.; Weis, Matthew R.; Porter, John L.

    2018-02-01

    The size, temporal and spatial shape, and energy content of a laser pulse for the pre-heat phase of magneto-inertial fusion affect the ability to penetrate the window of the laser-entrance-hole and to heat the fuel behind it. High laser intensities and dense targets are subject to laser-plasma-instabilities (LPI), which can lead to an effective loss of pre-heat energy or to pronounced heating of areas that should stay unexposed. While this problem has been the subject of many studies over the last decades, the investigated parameters were typically geared towards traditional laser driven Inertial Confinement Fusion (ICF) with densities either at 10% and above or at 1% and below the laser's critical density, electron temperatures of 3-5 keV, and laser powers near (or in excess of) 1 × 1015 W/cm2. In contrast, Magnetized Liner Inertial Fusion (MagLIF) [Slutz et al., Phys. Plasmas 17, 056303 (2010) and Slutz and Vesey, Phys. Rev. Lett. 108, 025003 (2012)] currently operates at 5% of the laser's critical density using much thicker windows (1.5-3.5 μm) than the sub-micron thick windows of traditional ICF hohlraum targets. This article describes the Pecos target area at Sandia National Laboratories using the Z-Beamlet Laser Facility [Rambo et al., Appl. Opt. 44(12), 2421 (2005)] as a platform to study laser induced pre-heat for magneto-inertial fusion targets, and the related progress for Sandia's MagLIF program. Forward and backward scattered light were measured and minimized at larger spatial scales with lower densities, temperatures, and powers compared to LPI studies available in literature.

  14. Preheating ablation effects on the Rayleigh-Taylor instability in the weakly nonlinear regime

    International Nuclear Information System (INIS)

    Wang, L. F.; Ye, W. H.; He, X. T.; Sheng, Z. M.; Don, Wai-Sun; Li, Y. J.

    2010-01-01

    The two-dimensional Rayleigh-Taylor instability (RTI) with and without thermal conduction is investigated by numerical simulation in the weakly nonlinear regime. A preheat model κ(T)=κ SH [1+f(T)] is introduced for the thermal conduction [W. H. Ye, W. Y. Zhang, and X. T. He, Phys. Rev. E 65, 057401 (2002)], where κ SH is the Spitzer-Haerm electron thermal conductivity coefficient and f(T) models the preheating tongue effect in the cold plasma ahead of the ablation front. The preheating ablation effects on the RTI are studied by comparing the RTI with and without thermal conduction with identical density profile relevant to inertial confinement fusion experiments. It is found that the ablation effects strongly influence the mode coupling process, especially with short perturbation wavelength. Overall, the ablation effects stabilize the RTI. First, the linear growth rate is reduced, especially for short perturbation wavelengths and a cutoff wavelength is observed in simulations. Second, the second harmonic generation is reduced for short perturbation wavelengths. Third, the third-order negative feedback to the fundamental mode is strengthened, which plays a stabilization role. Finally, on the contrary, the ablation effects increase the generation of the third harmonic when the perturbation wavelengths are long. Our simulation results indicate that, in the weakly nonlinear regime, the ablation effects are weakened as the perturbation wavelength is increased. Numerical results obtained are in general agreement with the recent weakly nonlinear theories as proposed in [J. Sanz, J. Ramirez, R. Ramis et al., Phys. Rev. Lett. 89, 195002 (2002); J. Garnier, P.-A. Raviart, C. Cherfils-Clerouin et al., Phys. Rev. Lett. 90, 185003 (2003)].

  15. High Frequency Oscillatory Ventilation

    Directory of Open Access Journals (Sweden)

    AC Bryan

    1996-01-01

    Full Text Available High frequency oscillatory (HFO ventilation using low tidal volume and peak airway pressures is extremely efficient at eliminating carbon dioxide and raising pH in the newborn infant with acute respiratory failure. Improvement in oxygenation requires a strategy of sustained or repetitive inflations to 25 to 30 cm H2O in order to place the lung on the deflation limb of the pressure-volume curve. This strategy has also been shown to decrease the amount of secondary lung injury in animal models. Experience of the use of HFO ventilation as a rescue therapy as well as several published controlled trials have shown improved outcomes and a decrease in the use of extracorporeal membrane oxygenation when it has been used in newborns.

  16. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

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

    cooling capacity, energy saving, low investment cost and low noise level; while the limitations include condensation risk and the limit on the room geometry. Furthermore, the crucial design parameters are summarized and their effects on the system performance are discussed. In addition to the stand...... 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...

  17. Damage to Preheated Tungsten Targets after Multiple Plasma Impacts Simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E.; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Makhlay, V.A.; Tereshin, V.I. [Kharkov Inst. of Physics and Technology, Inst. of Plasma Physics of National Science Center, Akademicheskaya street, 1, 61108 Kharkov (Ukraine); Landman, I.; Pestchanyi, S. [FZK-Forschungszentrum Karlsruhe, Association Euratom-FZK, Technik und Umwelt, Postfach 3640, D-7602 1 Karlsruhe (Germany)

    2007-07-01

    Full text of publication follows: The energy loads onto ITER divertor surfaces associated with the Type I ELMs are expected to be up to 1 MJ/m{sup 2} during 0.1-0.5 ms, with the number of pulses about 103 per discharge. Tungsten is a candidate material for major part of the surface, but its brittleness can result in substantial macroscopic erosion after the repetitive heat loads. To minimize the brittle destruction, tungsten may be preheated above the ductile-to-brittle transition temperature. In this work the behavior of preheated tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 450 pulses of the duration 0.25 ms and the heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is respectively below and above the melting threshold. During the exposures the targets were permanently kept preheated at 650 deg. C by a heater at target backside. In the course of exposures the irradiated surfaces were examined after regular numbers of pulses using the SEM and the optical microscopy. The profilometry, XRD, microhardness and weight loss measurements have been performed, as well as comparisons of surface damages after the heat loads both below and above the melting threshold. It is obtained that macro-cracks do not develop on the preheated surface. After the impacts with surface melting, a fine mesh of intergranular microcracks has appeared. The width of fine intergranular cracks grows with pulse number, achieving 1-1.5 microns after 100 pulses, and after 210 pulses the crack width increases up to 20 microns, which is comparable with grain sizes. Threshold changes in surface morphology resulting in corrugation structures and pits on the surface as well as importance of surface tension in resulted 'micro-brush' structures are discussed. Further evolution of the surface pattern is caused by loss of separated grains on exposed

  18. Experimental and analytical evaluation of preheating temperature during multipass repair welding

    Directory of Open Access Journals (Sweden)

    Sedmak Aleksandar S.

    2017-01-01

    Full Text Available Experimental measurement and analytical calculation of preheating, i. e. interpass temperature during multi-pass repair welding has been presented. Analytical calculation is based on heat transfer analysis, whereas measurements have been performed by thermovision camera. Repair welding was performed on crane wheels in the Steelworks Smederevo. Comparison of results indicated that analytical calculation is good enough as the first approximation, but it needs further elaboration, e. g. taking into account the radiation component of heat dissipation and/or temperature dependence of material thermomechanical properties.

  19. Pretreatment and preheating of scrap. Tarkastelu koskien romun esikaesittely- ja esikuumennusmenetelmiae

    Energy Technology Data Exchange (ETDEWEB)

    Hooli, P.; Hanni, J. (Outokumpu Oy Tornion Tehtaat, Tornio (Finland))

    1990-01-01

    As a background for this study has been those demands for scrap treatments and transportation, which are coming with increasing production of melting shop of Outokumpu Oy's Tornio works and also problems caused by snow among productionrate. Different pretreatment-, transport-, and preheatingmethods and some alternatives has been studied to arrange those as a functioning complete. Also very exact plannings for some pretreatmentmethods has been made. From preheatingmethods some methods, which are concerned to be effective and possible in the future has been studied. In addition those parameters, which are involved to the effectivity of preheating process in melting shop of Outokumpu Oy's Tornio works has been examined.

  20. Pretreatment and preheating of scrap; Tarkastelu koskien romun esikaesittely- ja esikuumennusmenetelmiae

    Energy Technology Data Exchange (ETDEWEB)

    Hooli, P.; Hanni, J. [Outokumpu Oy Tornion Tehtaat, Tornio (Finland)

    1990-12-31

    As a background for this study has been those demands for scrap treatments and transportation, which are coming with increasing production of melting shop of Outokumpu Oy`s Tornio works and also problems caused by snow among productionrate. Different pretreatment-, transport-, and preheatingmethods and some alternatives has been studied to arrange those as a functioning complete. Also very exact plannings for some pretreatmentmethods has been made. From preheatingmethods some methods, which are concerned to be effective and possible in the future has been studied. In addition those parameters, which are involved to the effectivity of preheating process in melting shop of Outokumpu Oy`s Tornio works has been examined.

  1. Harnessing natural ventilation benefits.

    Science.gov (United States)

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

  2. Purge ventilation operability

    International Nuclear Information System (INIS)

    Marella, J.R.

    1995-01-01

    A determination of minimum requirements for purge exhaust ventilation system operability has been performed. HLWE and HLW Regulatory Program personnel have evaluated the various scenarios of equipment conditions and HLWE has developed the requirements for purge exhaust systems. This report is provided to document operability requirements to assist Tank Farm personnel to determine whether a system is operable/inoperable and to define required compensatory actions

  3. Ventilation i industrien

    DEFF Research Database (Denmark)

    Valbjørn, O.

    I en række afsnit belyses problemer med træk, kulde, varme, og luftforurening på industriens arbejdspladser, og hvordan man ved ventilation og bygningsudformning kan bekæmpe disse gener. Hvert afsnit kan i princippet læses for sig, og anvisningen kan derfor bruges som håndbog, både af de der er...

  4. Measurement of the thermal function of a multifunctional solar cell and wall; Maaling af den termiske funktion af en multifunktionel solcellegavl

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.

    2002-05-01

    A 75 m{sup 2} multifunctional PV-gable has been erected on a building at Viktoriagade 10B close to the centre of Copenhagen. The PV-gable serves several purposes except for producing electricity to the grid There is an air gap between the PV-panels and the existing wall. This air gap acts as a combination of a bufferezone and solar air collector. The air gap further cools the backside of the PV-panels in order to increase the performance of the PV panels. The bufferzone decreases the heat loss through the gable. Thermostat controlled fresh air intakes are located at each floor of the 5 story building in order to let in buoyancy driven preheated fresh air to the building. The PV-gable further preheats the fresh air to two mechanical ventilation systems: a fresh air intake system on the third floor and a balanced ventilation system with heat recovery on the fourth floor. The present report deals only with the thermal performance of the PV-gable. Based on measurements on the multifunctional PV-gable and simulations with a simple computer model developed based on the measurements the following conclusions have been obtained. 1) the efficiency of the PV-gable as solar air collector is at least as could be expected. 2) the top of the PV-gable has the same insulating effect as traditional additional insulation with 100 mm mineral wool while the bottom of the PV-gable is half as good. 3) the efficiency of the heat exchanger on the fourth floor is as high as expected: at identical volume flow rates on each side of the heat exchanger the efficiency is between 75 and 83 %. In the actual case where the flow rate of exhaust air is higher than the flow rate of fresh air the efficiency was found to be 70 %. 4) based on simulations the thermal performance of the PV-gable is estimated to lay between the savings of traditional additional insulation of 100 mm mineral wool and four times the savings of traditional additional insulation depending on the chosen setpoints and volume flow

  5. Noninvasive Ventilation in Premature Neonates.

    Science.gov (United States)

    Flanagan, Keri Ann

    2016-04-01

    The use of noninvasive ventilation is a constantly evolving treatment option for respiratory disease in the premature infant. The goals of these noninvasive ventilation techniques are to improve gas exchange in the premature infant's lungs and to minimize the need for intubation and invasive mechanical ventilation. The goals of this article are to consider various uses of nasal interfaces, discuss skin care and developmental positioning concerns faced by the bedside nurse, and discuss the medical management aimed to reduce morbidity and mortality. This article explores the nursing role, the advances in medical strategies for noninvasive ventilation, and the team approach to noninvasive ventilation use in this population. Search strategy included a literature review on medical databases, such as EBSCOhost, CINAHL, PubMed, and NeoReviews. Innovative products, nursing research on developmental positioning and skin care, and advanced medical management have led to better and safer outcomes for premature infants requiring noninvasive ventilation. The medical focus of avoiding long-term mechanical ventilation would not be possible without the technology to provide noninvasive ventilation to these premature infants and the watchful eye of the nurse in terms of careful positioning, preventing skin breakdown and facial scarring, and a proper seal to maximize ventilation accuracy. This article encourages nursing-based research to quantify some of the knowledge about skin care and positioning as well as research into most appropriate uses for noninvasive ventilation devices.

  6. A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

    International Nuclear Information System (INIS)

    Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu; Zhang, Baohan; Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming

    2016-01-01

    During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

  7. A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu, E-mail: yqgu@caep.cn; Zhang, Baohan [Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); and others

    2016-06-15

    During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

  8. The effect of repeated preheating of dimethacrylate and silorane-based composite resins on marginal gap of class V restorations.

    Science.gov (United States)

    Alizadeh Oskoee, Parnian; Pournaghi Azar, Fatemeh; Jafari Navimipour, Elmira; Ebrahimi Chaharom, Mohammad Esmaeel; Naser Alavi, Fereshteh; Salari, Ashkan

    2017-01-01

    Background. One of the problems with composite resin restorations is gap formation at resin‒tooth interface. The present study evaluated the effect of preheating cycles of silorane- and dimethacrylate-based composite resins on gap formation at the gingival margins of Class V restorations. Methods. In this in vitro study, standard Class V cavities were prepared on the buccal surfaces of 48 bovine incisors. For restorative procedure, the samples were randomly divided into 2 groups based on the type of composite resin (group 1: di-methacrylate composite [Filtek Z250]; group 2: silorane composite [Filtek P90]) and each group was randomly divided into 2 subgroups based on the composite temperature (A: room temperature; B: after 40 preheating cycles up to 55°C). Marginal gaps were measured using a stereomicroscope at ×40 and analyzed with two-way ANOVA. Inter- and intra-group comparisons were analyzed with post-hoc Tukey tests. Significance level was defined at P composite resin type, preheating and interactive effect of these variables on gap formation were significant (Pcomposite resins (Pcomposite resins at room temperature compared to composite resins after 40 preheating cycles (Pcomposite re-sins. Preheating of silorane-based composites can result in the best marginal adaptation.

  9. Performance evaluation of ventilation radiators

    International Nuclear Information System (INIS)

    Myhren, Jonn Are; Holmberg, Sture

    2013-01-01

    A ventilation radiator is a combined ventilation and heat emission unit currently of interest due to its potential for increasing energy efficiency in exhaust-ventilated buildings with warm water heating. This paper presents results of performance tests of several ventilation radiator models conducted under controlled laboratory conditions. The purpose of the study was to validate results achieved by Computational Fluid Dynamics (CFD) in an earlier study and identify possible improvements in the performance of such systems. The main focus was on heat transfer from internal convection fins, but comfort and health aspects related to ventilation rates and air temperatures were also considered. The general results from the CFD simulations were confirmed; the heat output of ventilation radiators may be improved by at least 20% without sacrificing ventilation efficiency or thermal comfort. Improved thermal efficiency of ventilation radiators allows a lower supply water temperature and energy savings both for heating up and distribution of warm water in heat pumps or district heating systems. A secondary benefit is that a high ventilation rate can be maintained all year around without risk for cold draught. -- Highlights: ► Low temperature heat emitters are currently of interest due to their potential for increasing energy efficiency. ► A ventilation radiator is a combined ventilation and heat emission unit which can be adapted to low temperature heating systems. ► We examine how ventilation radiators can be made to be more efficient in terms of energy consumption and thermal comfort. ► Current work focuses on heat transfer mechanisms and convection fin configuration of ventilation radiators

  10. The performance of a Solar Aided Power Generation plant with diverse “configuration-operation” combinations

    International Nuclear Information System (INIS)

    Qin, Jiyun; Hu, Eric; Nathan, Graham J.

    2016-01-01

    Highlights: • Four configurations of solar preheaters have been proposed. • Three typical operation strategies of solar preheaters have been identified. • 12 “configuration-operation” combinations has been proposed. • There are superior combinations to achieve the highest solar thermal performance. - Abstract: Solar Aided Power Generation is an efficient way to integrate solar thermal energy into a fossil fuel fired power plant for solar power generation purposes. In this particular power plant, the solar heat is used to displace the extraction steam to preheat the feedwater to the boiler. The heat exchanger, which facilitates the heat exchange between the solar heat carried by the heat transfer fluid and the feedwater, is termed a solar preheater. Four possible configurations of the solar preheater, namely Parallel 1, Parallel 2, Series 1 and Series 2, are proposed in this paper. In this type of plant, the extraction steam flow rates must be adjusted according to the solar input. The ways to control the extraction steam flow rates are termed solar preheater operation strategies. Three typical strategies: the Constant Temperature control, Variable Temperature control with high to low temperature feedwater heater displacement and Variable Temperature control with low to high temperature feedwater heater displacement have been identified. Each configuration can be operated with one of the three strategies, resulting in twelve “configuration-operation” combinations/scenarios (shown in Table 1). Previous assessments and modelling of such a plant have only been based on a single combination. In this paper, a Solar Aided Power Generation plant, modified from a typical 300 MW power plant, is used to understand the plant’s performance for all twelve of the available combinations. The results show that the instantaneous and annual technical performances of such a plant are dependent on the combinations used. The scenario 10 (Table 1) is superior to the

  11. Solar production of lime; Solare Herstellung von Kalk

    Energy Technology Data Exchange (ETDEWEB)

    Meier, A.; Bonaldi, E.

    2002-07-01

    A novel indirect-heated solar reactor for the solar production of lime (CaO) was designed, built and tested in a solar furnace at the Paul Scherrer Institute PSI, at Villigen, Switzerland. This 10-kW reactor is operated in continuous mode and consists of a tilted rotary kiln with a specially designed high-temperature resistant blackbody absorber made from SiC and a preheating chamber where the small-grained limestone particles are preheated almost to the reaction temperature. The transition to an indirect-heated reactor including additional design changes was successful: (1) With the improved particle feeding system, the maximum CaO production rate was increased from 1.5 kg/hr to about 4 kg/hr. (2) The heat losses were significantly reduced, and consequently the reactor efficiency was increased to more than 30% with a maximum near 35%, while still maintaining a high degree of calcination exceeding 98%. (3) The SiC absorber withstood thermal shocks at temperatures up to 1,600 K. (author)

  12. Pretest Predictions for Ventilation Tests

    International Nuclear Information System (INIS)

    Y. Sun; H. Yang; H.N. Kalia

    2007-01-01

    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

  13. Capturing energy from ventilation air methane a preliminary design for a new approach

    International Nuclear Information System (INIS)

    Cluff, D.L.; Kennedy, G.A.; Bennett, J.G.; Foster, P.J.

    2015-01-01

    Methane is a potent greenhouse gas (GHG), discharged to the atmosphere by coalmining, the natural gas industry and natural biological processes, second only to carbon dioxide; thus, any reduction in atmospheric methane would be globally beneficial. The capture or use of ventilation air methane (VAM) is challenging because it is a high volume low concentration methane source. This results in the routine discharge of methane into the atmosphere. A review of VAM mitigation technologies is provided and the main disadvantages of the existing technologies are discussed. In the proposed VamTurBurner © system, the heat from the combustion chamber is transferred to the preheating zone either by a heat exchanger or by redirecting the combustion products to mix with the ventilation air stream from a coalmine. Gas turbines (GT) are used to produce electricity with the exhaust gases directed to mix with the incoming ventilation airflow. The turbulence introduced by the GT exhaust assists with mixing of the incoming ventilation airflow and the return flow of combustion products from the combustion chamber. The combustion products are a source of heat, which increases the temperature of the incoming ventilation air to a value high enough for the methane to undergo flameless combustion upon encountering the igniters. The high temperature combustion products enter a multi-generation system. The multi-generation system is based on mature engineering technology such as heat exchangers and steam turbines. The residual heat provides additional heat based products such as industrial scale drying, chilling by an absorption chiller or simply hot water. The VamTurBurner © uses the energy from the GT, igniters and VAM to provide clean efficient energy while mitigating the atmospheric emissions of methane. The opportunity to collect carbon credits may improve the economics. Since the VAM is a free energy source, the output of the system is greater than the purchased energy. - Highlights:

  14. Experimental study of a single fuel jet in conditions of highly preheated air combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lille, Simon; Blasiak, W. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy

    2000-04-01

    Highly Preheated Air Combustion (HPAC) is a technique to reduce consumption of fuel and decrease NO{sub x} formation in furnaces. The main change that occur in the furnace chamber is that the flow pattern of flue gases changes dramatically resulting in a more uniform heat transfer. The usefulness of regenerative combustion is very clear, but the advantages have so far been accompanied by high levels of pollutants, such as NO{sub x}. The combination of the regeneration technique and internal flue gas recirculation, thus decreasing NO{sub x} and keeping the other advantages, has made HPAC a very attractive combustion technology with application to heat treatment reheating and melting processes. This work gives an introduction to regenerative combustion with diluted air, including theory on flame stabilization. Furthermore, a description of a new test furnace is given with results from a parametric study and from tests using schlieren color visualization, direct photography, and laser Doppler anemometry. In the parametric study NO{sub x}-emission, CO-emission, lift-off, fluctuations, and some flame characteristics are related to nozzle diameter, oxygen concentration, and preheat temperature. For the schlieren technique and direct photography, both still and high-speed cameras were used.

  15. Gravitational waves from Abelian gauge fields and cosmic strings at preheating

    International Nuclear Information System (INIS)

    Dufaux, Jean-Francois; Figueroa, Daniel G.; Garcia-Bellido, Juan

    2010-01-01

    Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space. We show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearance of new peaks at characteristic frequencies that are related to the mass scales in the problem. We also show how these new features in the spectra correlate with stringlike spatial configurations in both the Higgs and gauge fields that arise due to the appearance of topological winding numbers of the Higgs around Nielsen-Olesen strings. We study in detail the time evolution of the spectrum of gauge fields and gravitational waves as these strings evolve and decay before entering a turbulent regime where the gravitational wave energy density saturates.

  16. Symbiotic potential: the integration of preheating and dry cooling in cokemaking

    Energy Technology Data Exchange (ETDEWEB)

    Barker, J E [British Carbonization Research Association, England; Bruce, J M; Kemmetmueller, R

    1978-06-01

    The expression closed energy cycle has become popular in the last decade as descriptive of industrial systems in which exhaust heat is recovered from a primary energy-conversion stage and utilized either recuperatively or regeneratively within the overall complex. An old and well-proven means of utilizing the sensible heat of the incandescent coke discharged from coke ovens is known as dry cooling. This is being practiced widely in the USSR and Japan, but not yet to any significant extent in the western world. The waste heat recovered by this system is normally used to raise steam for power generation and process use. A recent advance in the carbonization of coal for the manufacture of metallurgical coke has been the application of the technique of coal drying and preheating as a means of improving both coke quality and oven productivity, and this is usually energized by burning gas as a fuel. An alternative configuration, having practical advantages in relation to efficiency of utilization of recovered energy and to safety in operation, is represented by a combination of coal drying and preheating with dry cooling of the coke. This paper is concerned with the case for this combination and the means whereby it may be effected in practice. The energy cycle of cokemaking would thus be more nearly closed.

  17. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Effect of preheat repetition on color stability of methacrylate- and silorane-based composite resins.

    Science.gov (United States)

    Abed Kahnamouei, Mehdi; Gholizadeh, Sarah; Rikhtegaran, Sahand; Daneshpooy, Mehdi; Kimyai, Soodabeh; Alizadeh Oskoee, Parnian; Rezaei, Yashar

    2017-01-01

    Background. The aim of this study was to investigate the effect of preheating methacrylate- and silorane-based composite resins on their color stability up to 40 times at 55‒60°C. Methods. Seventy-six methacrylate and silorane-based composite resin samples, with a diameter of 10 mm and a height of 2 mm, were divided into 4 groups (n=19). After the samples were prepared, their color parameters were determined using a reflective spectrophotometer. The composite resin samples were separately stored in a solution of tea for 40 consecutive days. Then the samples underwent a color determination procedure again using a spectrophotometer and color changes were recorded. Finally two-way ANOVA was used to study the effect of composite temperature on its staining (Pcomposite resin samples compared to non-heated samples at P=0.005 and P=0.029 for silorane-based and Z250 composite resin samples, respectively. Results. Both composite resin type (P=0.014) and preheating (Pcomposite resin samples, up to 55‒60°C for 40 rounds, resulted in more color changes compared with unheated composite resin samples. After storage in a solution of tea the color change rate in the composite resin samples of silorane-based was higher than the Z250 composite resin samples.

  19. Non-Gaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation

    Science.gov (United States)

    Barnaby, Neil; Cline, James M.

    2006-05-01

    We show that in hybrid inflation it is possible to generate large second-order perturbations in the cosmic microwave background due to the instability of the tachyonic field during preheating. We carefully calculate this effect from the tachyon contribution to the gauge-invariant curvature perturbation, clarifying some confusion in the literature concerning nonlocal terms in the tachyon curvature perturbation; we show explicitly that such terms are absent. We quantitatively compute the non-Gaussianity generated by the tachyon field during the preheating phase and translate the experimental constraints on the nonlinearity parameter fNL into constraints on the parameters of the model. We also show that nonscale-invariant second-order perturbations from the tachyon field with spectral index n=4 can become larger than the inflaton-generated first-order perturbations, leading to stronger constraints than those coming from non-Gaussianity. The width of the excluded region in terms of the logarithm of the dimensionless coupling g, grows linearly with the log of the ratio of the Planck mass to the tachyon VEV, log⁡(Mp/v); hence very large regions are ruled out if the inflationary scale v is small. We apply these results to string-theoretic brane-antibrane inflation, and find a stringent upper bound on the string coupling, gs<10-4.5.

  20. Modification of preheated tungsten surface after irradiation at the GOL-3 facility

    Energy Technology Data Exchange (ETDEWEB)

    Shoshin, A.A., E-mail: shoshin@mail.ru [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Arakcheev, A.S.; Arzhannikov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Burdakov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, Novosibirsk 630092 (Russian Federation); Huber, A. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Ivanov, I.A. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Kuklin, K.N. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Polosatkin, S.V.; Postupaev, V.V.; Sinitsky, S.L. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vasilyev, A.A. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2016-12-15

    Highlights: • Preheated tungsten was irradiated at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. • The crack pattern and the quantity of bubbles depend on the initial temperatures of the target. • The orientation of major crack networks correlates with the direction of machining of the samples. • Dust impact craters were found. - Abstract: The study is devoted to tungsten surface modification after irradiation at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. In order to emulate heating with a steady plasma flux in the ITER divertor, some of the tungsten samples were preheated up to 500 °C. It was found out that the behavior of the surface modification (the crack pattern and the number of bubbles) depends on the initial temperature of the targets. While the orientation of major crack networks correlates with the direction of machining of the samples. Afterwards we have observed the process of craters’ formation caused by dust particle impacts.

  1. Design Principles for Natural and Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples.......For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation...

  2. Residential solar hot water

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-01

    This report examines the feasibility of using solar energy to preheat domestic water coming from the city supply at a temperature of approximately 4{degree}C. Four solar collectors totalling 7 m{sup 2} were installed on a support structure facing south at an angle of 60{degree} from the horizontal. The system worked most efficiently in the spring and early summer when the combination of long hours of sunshine, clean air and clear skies allowed for maximum availability of solar radiation. Performance dropped in late summer and fall mainly due to cloudier weather conditions. The average temperature in the storage tank over the 10 months of operation was 42{degree}C, ranging from a high of 83{degree}C in July to a low of 6{degree}C in November. The system provided a total of 7.1 GJ, which is approximately one-third the annual requirement for domestic hot water heating. At the present time domestic use of solar energy to heat water does not appear to be economically viable. High capital costs are the main problem. As a solar system with present day technology can only be expected to meet half to two-thirds of the hot water energy demand the savings are not sufficient for the system to pay for itself within a few years. 5 figs.

  3. Influence of the urban environment on the effectiveness of natural night-ventilation of an office building

    NARCIS (Netherlands)

    Ramponi, R.; Gaetani, I.; Angelotti, A.

    2014-01-01

    The effectiveness of natural night-ventilation in the urban environment depends on local climate characteristics, but also on solar shading and wind shielding effects of the surrounding buildings. However, the impact of the latter factors on the effectiveness of night-ventilation is often

  4. Mechanical ventilation in neurosurgical patients

    Directory of Open Access Journals (Sweden)

    Keshav Goyal

    2013-01-01

    Full Text Available Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical patient requiring artificial support of the respiration.

  5. Mechanical Ventilation and Bronchopulmonary Dysplasia.

    Science.gov (United States)

    Keszler, Martin; Sant'Anna, Guilherme

    2015-12-01

    Mechanical ventilation is an important potentially modifiable risk factor for the development of bronchopulmonary dysplasia. Effective use of noninvasive respiratory support reduces the risk of lung injury. Lung volume recruitment and avoidance of excessive tidal volume are key elements of lung-protective ventilation strategies. Avoidance of oxidative stress, less invasive methods of surfactant administration, and high-frequency ventilation are also important factors in lung injury prevention. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Improved model for solar heating of buildings

    OpenAIRE

    Lie, Bernt

    2015-01-01

    A considerable future increase in the global energy use is expected, and the effects of energy conversion on the climate are already observed. Future energy conversion should thus be based on resources that have negligible climate effects; solar energy is perhaps the most important of such resources. The presented work builds on a previous complete model for solar heating of a house; here the aim to introduce ventilation heat recovery and improve on the hot water storage model. Ventilation he...

  7. Design Principles for Natural and Hybrid Ventilation

    OpenAIRE

    Heiselberg, Per

    2000-01-01

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples.

  8. 46 CFR 42.15-45 - Ventilators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ventilators. 42.15-45 Section 42.15-45 Shipping COAST... Conditions of Assignment of Freeboard § 42.15-45 Ventilators. (a) Ventilators in position 1 or 2 to spaces... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing...

  9. Application of solar energy; Proceedings of the Third Southeastern Conference, Huntsville, Ala., April 17-19, 1978

    Science.gov (United States)

    Wu, S. T. (Editor); Christensen, D. L.; Head, R. R.

    1978-01-01

    Demonstration projects, systems-subsystems simulation programs, applications (heating, cooling, agricultural, industrial), and climatic data testing (standards, economics, institutional) are the topics of the book. Economics of preheating water for commercial use and collecting, processing, and dissemination of data for the national demonstration program are discussed. Computer simulation of a solar energy system and graphical representation of solar collector performance are considered. Attention is given to solar driven heat pumps, solar cooling equipment, hybrid passive/active solar systems, and solar farm buildings. Evaluation of a thermographic scanning device for solar energy and conservation applications, use of meteorological data in system evaluation, and biomass conversion potential are presented.

  10. Field test measurements and system optimisation at a solar operated DEC ventilation system at industrial use; Feldtest-Messungen und Systemoptimierung an einer solarbetriebenen DEC-Klimatisierungsanlage im industriellen Einsatz

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Tobias; Finkenzeller, Michael; Trinkl, Christoph; Zoerner, Wilfried [Hochschule Ingolstadt (Germany). Kompetenzfeld Erneuerbare Energien

    2010-07-01

    The field of competence for renewable energy at the Ingolstadt University (Federal Republic of Germany) examines and optimizes an innovative, solar powered air conditioning system with DEC technology (DEC = Desiccant and Evaporative Cooling) in a multi-functional industrial buildings. In addition to a geothermal heat pump system for basic energy supply of heating and cooling, the building is fitted with two solar thermal solar collector panels and a sorption supported air conditioning system. This air conditioner consists of two units, each with a nominal air flow of 8,000 m{sup 3} per hour. The two solar collector panels provide the heat necessary for the regeneration of the sorption rotors and support the domestic preparation of hot water.

  11. Investigation of Indoor Climate in a Naturally Ventilated Office Building

    DEFF Research Database (Denmark)

    Larsen, Tine Steen; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    A measuring program in a naturally ventilated office building in Copenhagen was carried out to document the indoor climate and ventilation system performance during a year. It included a questionnaire regarding the perceived indoor environmental quality and physical measurements of thermal comfort...... to a combination of poor control of solar shading and a very high local heat load that was above the Danish recommendations for naturally ventilated office buildings. Both measured and perceived indoor air quality in the building was in general very high. The measured air flow rates was relatively high due...... to the need for cooling in the office building, while the level of infiltration was quite low indicating an airtight construction....

  12. Effect of the Preheating Temperature on Process Time in Friction Stir Welding of Al 6061-T6

    DEFF Research Database (Denmark)

    Jabbari, Masoud

    2013-01-01

    This paper presents the results obtained and the deductions made from an analytical modeling involving friction stir welding of Al 6061-T6. A new database was developed to simulate the contact temperature between the tool and the workpiece. A second-order equation is proposed for simulating...... the temperature in the contact boundary and the thermal history during the plunge phase. The effect of the preheating temperature on the process time was investigated with the proposed model. The results show that an increase of the preheating time leads to a decrease in the process time up to the plunge...

  13. Naturlig ventilation i enfamiliehuse

    DEFF Research Database (Denmark)

    Bergsøe, N.C.

    Meddelelsen beskriver resultaterne af en række beregninger foretaget ved anvendelse af et computerprogram. Beregningerne har til formål at belyse forskellige parametres indvirkning på funktionen af et naturligt ventilationssystem. Blandt andet belyses systemets afhængighed af aftrækskanalernes di...... dimension, udeluftventilarealet og placeringen af aftrækskanalernes udmunding i tagfladen. Derudover gengives i kortfattet form de væsentligste konklusioner af udvalgte publikationer, som behandler særlige forhold vedrørende naturlig ventilation i praksis....

  14. Solar project description for Public Service Company of New Mexico (lot 7) single family residence, Rio Rancho, New Mexico

    Science.gov (United States)

    1981-08-01

    A solar space heating/domestic hot water system employing 150 square feet air flat plate collectors and 20,000 pounds of rock for storage is described. The collector, storage, energy to load, and auxiliary heat subsystems and five modes of operation are described. Auxiliary space heating is provided by an electric strip heater in the air ducts. The hot water system consists of an 80 gallon solar preheating tank which supplies a 40 gallon conventional tank. An electric heating element provides auxiliary heating in the preheat tank.

  15. Radioaerosol ventilation imaging in ventilator-dependent patients. Technical considerations

    International Nuclear Information System (INIS)

    Vezina, W.; Chamberlain, M.; Vinitski, S.; King, M.; Nicholson, R.; Morgan, W.K.

    1985-01-01

    The differentiation of pulmonary embolism (PE) from regional ventilatory abnormalities accompanied by reduced perfusion requires contemporary perfusion and ventilation studies. Distinguishing these conditions in ventilator-dependent patients is aided by administering a Tc-99m aerosol to characterize regional ventilation, and by performing a conventional Tc-99m MAA perfusion study. The technique uses a simple in-house constructed apparatus. Simple photographic techniques suffice, but computer subtraction of perfusion from the combined perfusion-ventilation image renders interpretation easier if aerosol administration follows perfusion imaging. Multiple defects can be examined in a single study. Excluding normal or near-normal perfusion studies, PE was thought to be present in eight of 16 patients after perfusion imaging alone, but in only one of eight after added aerosol imaging. Angiography confirmed the diagnosis in that patient. Of the eight patients who had abnormal perfusion but were thought unlikely to have PE from the perfusion study alone, two had normal ventilation, and subsequently were shown to have PE by angiography. Because angiography was only performed on patients who were thought to have a high probability of PE on sequential perfusion-ventilation imaging, the true incidence of PE may have been higher. Aerosol ventilation imaging is a useful adjunct to perfusion imaging in patients on ventilators. It requires an efficient delivery system, particularly if aerosol administration follows perfusion imaging, as it does in this study

  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. [Lung protective ventilation. Ventilatory modes and ventilator parameters].

    Science.gov (United States)

    Schädler, Dirk; Weiler, Norbert

    2008-06-01

    Mechanical ventilation has a considerable potential for injuring the lung tissue. Therefore, attention has to be paid to the proper choice of ventilatory mode and settings to secure lung-protective ventilation whenever possible. Such ventilator strategy should account for low tidal volume ventilation (6 ml/kg PBW), limited plateau pressure (30 to 35 cm H2O) and positive end-expiratory pressure (PEEP). It is unclear whether pressure controlled or volume controlled ventilation with square flow profile is beneficial. The adjustment of inspiration and expiration time should consider the actual breathing mechanics and anticipate the generation of intrinsic PEEP. Ventilatory modes with the possibility of supporting spontaneous breathing should be used as soon as possible.

  18. A FOCUSED TRANSPORT APPROACH TO THE TIME-DEPENDENT SHOCK ACCELERATION OF SOLAR ENERGETIC PARTICLES AT A FAST TRAVELING SHOCK

    International Nuclear Information System (INIS)

    Le Roux, J. A.; Webb, G. M.

    2012-01-01

    Some of the most sophisticated models for solar energetic particle (SEP) acceleration at coronal mass ejection driven shocks are based on standard diffusive shock acceleration theory. However, this theory, which only applies when SEP pitch-angle anisotropies are small, might have difficulty in describing first-order Fermi acceleration or the shock pre-heating and injection of SEPs into first-order Fermi acceleration accurately at lower SEP speeds where SEP pitch-angle anisotropies upstream near the shock can be large. To avoid this problem, we use a time-dependent focused transport model to reinvestigate first-order Fermi acceleration at planar parallel and quasi-parallel spherical traveling shocks between the Sun and Earth with high shock speeds associated with rare extreme gradual SEP events. The focused transport model is also used to investigate and compare three different shock pre-heating mechanisms associated with different aspects of the nonuniform cross-shock solar wind flow, namely, the convergence of the flow (adiabatic compression), the shear tensor of the flow, and the acceleration of the flow, and a fourth shock pre-heating mechanism associated with the cross-shock electric field, to determine which pre-heating mechanism contributes the most to injecting shock pre-heated source particles into the first-order Fermi acceleration process. The effects of variations in traveling shock conditions, such as increasing shock obliquity and shock slowdown, and variations in the SEP source with increasing shock distance from the Sun on the coupled processes of shock pre-heating, injection, and first-order Fermi acceleration are analyzed. Besides the finding that the cross-shock acceleration of the solar wind flow yields the dominant shock pre-heating mechanism at high shock speeds, we find that first-order Fermi acceleration at fast traveling shocks differs in a number of respects from the predictions and assumptions of standard steady-state diffusive shock

  19. Improved Performance With Ventilation

    Science.gov (United States)

    Kawakami, Ellison; Lee, Seung Jae; Karn, Ashish; Hong, Jiarong; Arndt, Roger

    2013-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, ventilation is required to supply an artificial cavity until conditions at which a natural supercavity can be sustained are reached. Various aspects of the flow physics of a supercavitating vehicle have been under investigation for several years at Saint Anthony Falls Laboratory. Both steady flow and simulated flow below a wave train have been studied. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity to permit an in-depth study of unsteadiness. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are reviewed in light of new studies that focused on various closure mechanisms. Sponsored by ONR.

  20. Ventilator-associated pneumonia.

    Science.gov (United States)

    Shaw, Michael Jan

    2005-05-01

    This review summarises some of the notable papers on ventilator-associated pneumonia (VAP) from January 2003 to October 2004. Ventilator-associated pneumonia remains an important drain on hospital resources. All population groups are affected, but patients with VAP are more likely to be older, sicker, and male, with invasive medical devices in situ. Early VAP diagnosis is desirable to reduce VAP mortality and to retard emergence of multidrug-resistant microbes. This may be possible using preliminary culture results or intracellular organism in polymorphonuclear cells. In most intensive care units, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii are the commonest organisms isolated in VAP. However, causative organisms vary between and within hospitals. Consequently, individual intensive care units should develop empirical antibiotic policies to target the pathogenic bacteria prevalent in their patient populations. Preventative strategies aimed at reducing aerodigestive tract colonisation by pathogenic organisms, and also their subsequent aspiration, are becoming increasingly important. Educating medical staff about these simple measures is therefore pertinent. To reduce the occurrence of multidrug-resistant organisms, limiting the duration of antibiotic treatment to 8 days and antimicrobial rotation should be contemplated. Empirical therapy with antipseudomonal penicillins plus beta-lactamase inhibitors should be considered. If methicillin-resistant Staphylococcus aureus VAP is a possibility, linezolid may be better than vancomycin. Prevention remains the key to reducing VAP prevalence.

  1. 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 ...

  2. Innovation in home mechanical ventilation

    NARCIS (Netherlands)

    Hazenberg, Andrea

    2017-01-01

    Patients on home mechanical ventilation (HMV) are ventilator dependent, usually for the rest of their lives. In the past decades, the number of patients on HMV increased to nearly 3,000 in 2016 in the Netherlands. Current indications for HMV are patients diagnosed with either neuromuscular disease,

  3. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  4. Hybrid solar-PLG system for industrial scale steam and hot water generation; Sistema hibrido solar-GLP para geracao de vapor e agua quente em escala industrial

    Energy Technology Data Exchange (ETDEWEB)

    Saidel, Marco A.; Monteiro, Marcio D.; Gimenes, Andre L.V.; Fujii, Ricardo J. [Universidade de Sao Paulo (GEPEA/EPUSP), SP (Brazil). Dept. Engenharia Energia e Automacao Eletricas. Grupo de Energia], e-mail: saidel@pea.usp.br, e-mail: marcio.monteiro@poli.usp.br, e-mail: gimenes@gmail.com, e-mail: fujii@gmail.com

    2008-07-01

    This paper presents an initiative conceived for attending to objectives of the PUREFA (Program for Rational Use of Energy and Alternative Sources) of the Sao Paulo university, Brazil. The indicative consists of the implantation of a solar collector system for pre-heating of the water used in the production of the steam consumed at the university restaurant, with a production of 5800 meals per day. This system (auxiliary to the original steam boiler) pre-heats the water of the boiler minimizing the energy expenses for the production of steam and hot water.

  5. Summer Thermal Performance of Ventilated Roofs with Tiled Coverings

    International Nuclear Information System (INIS)

    Bortoloni, M; Bottarelli, M; Piva, S

    2017-01-01

    The thermal performance of a ventilated pitched roof with tiled coverings is analysed and compared with unventilated roofs. The analysis is carried out by means of a finite element numerical code, by solving both the fluid and thermal problems in steady-state. A whole one-floor building with a pitched roof is schematized as a 2D computational domain including the air-permeability of tiled covering. Realistic data sets for wind, temperature and solar radiation are used to simulate summer conditions at different times of the day. The results demonstrate that the batten space in pitched roofs is an effective solution for reducing the solar heat gain in summer and thus for achieving better indoor comfort conditions. The efficiency of the ventilation is strictly linked to the external wind conditions and to buoyancy forces occurring due to the heating of the tiles. (paper)

  6. Summer Thermal Performance of Ventilated Roofs with Tiled Coverings

    Science.gov (United States)

    Bortoloni, M.; Bottarelli, M.; Piva, S.

    2017-01-01

    The thermal performance of a ventilated pitched roof with tiled coverings is analysed and compared with unventilated roofs. The analysis is carried out by means of a finite element numerical code, by solving both the fluid and thermal problems in steady-state. A whole one-floor building with a pitched roof is schematized as a 2D computational domain including the air-permeability of tiled covering. Realistic data sets for wind, temperature and solar radiation are used to simulate summer conditions at different times of the day. The results demonstrate that the batten space in pitched roofs is an effective solution for reducing the solar heat gain in summer and thus for achieving better indoor comfort conditions. The efficiency of the ventilation is strictly linked to the external wind conditions and to buoyancy forces occurring due to the heating of the tiles.

  7. Solar Energy System Description Document: Scattergood School, Site ID 009, PON 2249.

    Science.gov (United States)

    International Business Machines Corp., Huntsville, AL.

    Described are the components, functions, and monitoring instrumentation of a solar heating system at Scattergood School, a Quaker school located in Iowa. The system provides the school gymnasium's space heating and preheating for domestic hot water. This project was constructed and is being evaluated under the United States Department of Energy's…

  8. Ventilation of an hydrofoil wake

    Science.gov (United States)

    Arndt, Roger; Lee, Seung Jae; Monson, Garrett

    2013-11-01

    Ventilation physics plays a role in a variety of important engineering applications. For example, hydroturbine ventilation is used for control of vibration and cavitation erosion and more recently for improving the dissolved oxygen content of the flow through the turbine. The latter technology has been the focus of an ongoing study involving the ventilation of an hydrofoil wake to determine the velocity and size distribution of bubbles in a bubbly wake. This was carried out by utilizing particle shadow velocimetry (PSV). This technique is a non-scattering approach that relies on direct in-line volume illumination by a pulsed source such as a light-emitting diode (LED). The data are compared with previous studies of ventilated flow. The theoretical results of Hinze suggest that a scaling relationship is possible that can lead to developing appropriate design parameters for a ventilation system. Sponsored by ONR and DOE.

  9. Natural ventilation for free stall dairy barns

    OpenAIRE

    Gay, Susan Wood

    2009-01-01

    Natural ventilation is a result of a combination good construction, correct temperature, humidity control, air exchange. This publication discusses how to achieve natural ventilation in your structure.

  10. Damage to preheated tungsten targets after multiple plasma impacts simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)], E-mail: garkusha@ipp.kharkov.ua; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Makhlaj, V.A. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Pestchanyi, S. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

    2009-04-30

    The behavior of a preheated at 650 deg. C tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 350 pulses of the duration 0.25 ms and the surface heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is below and above the melting threshold, respectively. The development of surface morphology of the exposed targets as well as cracking and swelling at the surface is discussed. First comparisons of obtained experimental results with corresponding numerical simulations of the code PEGASUS-3D are presented.

  11. New Colloidal Lithographic Nanopatterns Fabricated by Combining Pre-Heating and Reactive Ion Etching

    Directory of Open Access Journals (Sweden)

    Cong Chunxiao

    2009-01-01

    Full Text Available Abstract We report a low-cost and simple method for fabrication of nonspherical colloidal lithographic nanopatterns with a long-range order by preheating and oxygen reactive ion etching of monolayer and double-layer polystyrene spheres. This strategy allows excellent control of size and morphology of the colloidal particles and expands the applications of the colloidal patterns as templates for preparing ordered functional nanostructure arrays. For the first time, various unique nanostructures with long-range order, including network structures with tunable neck length and width, hexagonal-shaped, and rectangular-shaped arrays as well as size tunable nanohole arrays, were fabricated by this route. Promising potentials of such unique periodic nanostructures in various fields, such as photonic crystals, catalysts, templates for deposition, and masks for etching, are naturally expected.

  12. New pre-heating system for natural gas pressure regulating stations

    International Nuclear Information System (INIS)

    Zullo, G.; Vertuani, C.; Borghesani, O.; Vignoli, F.

    1999-01-01

    Costs for running natural gas pressure regulating stations are mainly due to operation and maintenance of a natural gas preheating system, usually equipment with a hot water boiler or an armour-plated electric resistance immersed in a fluid. The article describe a system, considering a natural circulation boiler which uses steam/condensate (at 100 degrees C and 0,5 bar) as a thermal conductor, in thermodynamic balance and in absence of un condensable. This new boiler, already operating with satisfactory results in heating system for industrial buildings, does not require testing, notifications, periodical inspections by the competent authorities, constant monitoring by trained or patented staff. Besides, it allows easier installations procedures and running cost savings. The system, to be considered as static because it has no moving parts, is a good alternative to conventional forced hot water circulation or electric heating system [it

  13. Preheat effect on titanium plate fabricated by sputter-free selective laser melting in vacuum

    Science.gov (United States)

    Sato, Yuji; Tsukamoto, Masahiro; Shobu, Takahisa; Yamashita, Yorihiro; Yamagata, Shuto; Nishi, Takaya; Higashino, Ritsuko; Ohkubo, Tomomasa; Nakano, Hitoshi; Abe, Nobuyuki

    2018-04-01

    The dynamics of titanium (Ti) melted by laser irradiation was investigated in a synchrotron radiation experiment. As an indicator of wettability, the contact angle between a selective laser melting (SLM) baseplate and the molten Ti was measured by synchrotron X-rays at 30 keV during laser irradiation. As the baseplate temperature increased, the contact angle decreased, down to 28° at a baseplate temperature of 500 °C. Based on this result, the influence of wettability of a Ti plate fabricated by SLM in a vacuum was investigated. It was revealed that the improvement of wettability by preheating suppressed sputtering generation, and a surface having a small surface roughness was fabricated by SLM in a vacuum.

  14. Solid state NMR studies for a new carbonization process with high temperature preheating

    Science.gov (United States)

    Saito, Koji; Hatakeyama, Moriaki; Komaki, Ikuo; Katoh, Kenji

    2002-01-01

    A new carbonization process with rapid preheating and coke discharging at medium temperature has been developed in Japan. The result of this process shows that even when no or slightly coking coal is by 50 wt% the coking property is improved and a coking coke with cold strength usable at blast furnace can be manufactured with the new carbonization process. The mechanism of the coking property improvement was examined by coal properties using mainly solid state NMR ( 1H CRAMPS and 13C SPE/MAS, CP/MAS) and NMR imaging (single point imaging, in-situ imaging). It has been clarified that the molecular structure of coal is relaxed by the rapid heating treatment and, in addition, there is a close relation between hydrogen bonding and relaxation of the molecular structure of coal.

  15. Study of sensitivity change of OSL signals from quartz and feldspars as a function of preheat temperature

    DEFF Research Database (Denmark)

    Jungner, H.; Bøtter-Jensen, L.

    1994-01-01

    and as a result, the equivalent dose (ED) would be underestimated. A study of sensitivity changes in feldspars and quartz was carried out with emphasis on the effect of preheat and annealing on the OSL signal. Measurement results obtained are presented, and possible elimination of errors in dating caused...

  16. Experimental and Modeling Investigation of the Effect of Air Preheat on the Formation of NOx in an RQL Combustor

    Science.gov (United States)

    Samuelsen, G. S.; Brouwer, J.; Vardakas, M. A.; Holderman, J. D.

    2012-01-01

    The Rich-burn/Quick-mix/Lean-burn (RQL) combustor concept has been proposed to minimize the formation of oxides of nitrogen (NOx) in gas turbine systems. The success of this low-NOx combustor strategy is dependent upon the links between the formation of NOx, inlet air preheat temperature, and the mixing of the jet air and fuel-rich streams. Chemical equilibrium and kinetics modeling calculations and experiments were performed to further understand NOx emissions in an RQL combustor. The results indicate that as the temperature at the inlet to the mixing zone increases (due to preheating and/or operating conditions) the fuel-rich zone equivalence ratio must be increased to achieve minimum NOx formation in the primary zone of the combustor. The chemical kinetics model illustrates that there is sufficient residence time to produce NOx at concentrations that agree well with the NOx measurements. Air preheat was found to have very little effect on mixing, but preheating the air did increase NOx emissions significantly. By understanding the mechanisms governing NOx formation and the temperature dependence of key reactions in the RQL combustor, a strategy can be devised to further reduce NOx emissions using the RQL concept.

  17. Utilization of biogas released from palm oil mill effluent for power generation using self-preheated reactor

    International Nuclear Information System (INIS)

    Hosseini, Seyed Ehsan; Wahid, Mazlan Abdul

    2015-01-01

    Highlights: • A lab-scale reactor called self-preheating flameless combustion (SPFC) system is experimented. • Feasibility of power generation by POME biogas is modeled using SPFC system. • 4 MW power is available by POME biogas utilization in a typical palm oil mill with 300,000 tons production. • The rate of power generation increases when 2% hydrogen is added to POME biogas ingredients. - Abstract: In palm oil mills, for one ton crude palm oil (CPO) production, 70 m"3 biogas is released from palm oil mill effluent (POME) which can endanger the environment. Palm oil mills without appropriate strategies for biogas collection can participate in greenhouse gases (GHGs) generation actively. In this paper, a typical palm oil mill with annual capacity of 300,000 ton oil palm production and 3 MW electricity demand is considered as a pilot plant and feasibility of power generation by POME biogas is modeled by Aspen Plus considering flameless mode in combustion system. A new design of lab-scale flameless reactor called self-preheated flameless combustion (SPFC) system is presented and employed in power generation modeling. In SPFC system, the flameless chamber is employed as a heater to preheat an oxidizer over the self-ignition temperature of the fuel. A helical stainless steel pipe (called self-preheating pipe) is installed inside the chamber to conduct the oxidizer from exhaust zone to the combustion zone inside the chamber and preheat oxidizer. In the flameless mode, the diluted oxidizer is injected to the helical pipe from the exhaust zone and the preheated oxidizer at the burner is conducted to the flameless furnace through a distributor. In SPFC system external heater for preheating oxidizer is removed and the rate of power generation increases. The results show that 10.8 MW power could be generated in ultra-lean POME biogas SPFC. However, the rate of pollutant especially CO_2 and NO_x is high in this circumstances. In stoichiometric condition, 4 MW power

  18. Hydrogen preheating through waste heat recovery of an open-cathode PEM fuel cell leading to power output improvement

    International Nuclear Information System (INIS)

    Mohamed, W.A.N.W.; Kamikl, M. Haziq M.

    2016-01-01

    Highlights: • A study on the effect of hydrogen preheating using waste heat for low temperature PEM fuel cells. • Theoretical, experimental and analytical framework was established. • The maximum electrical power output increases by 8–10% under specific operating conditions. • Open loop hydrogen supply gives a better performance than closed loop. • The waste heat utilization is less than 10% due to heat capacity limitations. - Abstract: The electrochemical reaction kinetics in a Polymer Electrolyte Membrane (PEM) fuel cell is highly influenced by the reactants supply pressures and electrode temperatures. For an open cathode PEM fuel cell stack, the power output is constrained due to the use of air simultaneously as reactant and coolant. Optimal stack operation temperatures are not achieved especially at low to medium power outputs. Based on the ideal gas law, higher reactant temperatures would lead to higher pressures and subsequently improve the reaction kinetics. The hydrogen supply temperature and its pressure can be increased by preheating; thus, slightly offsetting the limitation of low operating stack temperatures. The exit air stream offers an internal source of waste heat for the hydrogen preheating purpose. In this study, a PEM open-cathode fuel cell was used to experimentally evaluate the performance of hydrogen preheating based on two waste heat recovery approaches: (1) open-loop and (2) closed loop hydrogen flow. The stack waste heat was channelled into a heat exchanger to preheat the hydrogen line before it is being supplied (open loop) or resupplied (closed loop) into the stack. At a constant 0.3 bar hydrogen supply pressure, the preheating increases the hydrogen temperature in the range of 2–13 °C which was dependant on the stack power output and cathode air flow rates. The achievable maximum stack power was increased by 8% for the closed loop and 10% for the open loop. Due to the small hydrogen flow rates, the waste heat utilization

  19. [Oesophagitis during mechanical ventilation].

    Science.gov (United States)

    Gastinne, H; Canard, J M; Pillegand, B; Voultoury, J C; Catanzano, A; Claude, R; Gay, R

    1982-10-16

    Twenty-one patients whose condition required mechanical ventilation with nasogastric intubation were investigated for oesophagitis before the 3rd day and on the 15th day of treatment, including endoscopy and biopsy. Lesions of oesophagitis were detected in 14 cases during the initial examination and in 19 cases on the second endoscopy. The course of the lesions varied from one patient to another and appeared to be unrelated to the course of the primary disease. Oesophagitis in these patients is probably due to frequent episodes of gastro-oesophageal reflux encouraged by cough, impaired consciousness and the presence of a tube. Reflux may also be the cause of inapparent and recurrent lung aspiration.

  20. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  1. Estimation of Lung Ventilation

    Science.gov (United States)

    Ding, Kai; Cao, Kunlin; Du, Kaifang; Amelon, Ryan; Christensen, Gary E.; Raghavan, Madhavan; Reinhardt, Joseph M.

    Since the primary function of the lung is gas exchange, ventilation can be interpreted as an index of lung function in addition to perfusion. Injury and disease processes can alter lung function on a global and/or a local level. MDCT can be used to acquire multiple static breath-hold CT images of the lung taken at different lung volumes, or with proper respiratory control, 4DCT images of the lung reconstructed at different respiratory phases. Image registration can be applied to this data to estimate a deformation field that transforms the lung from one volume configuration to the other. This deformation field can be analyzed to estimate local lung tissue expansion, calculate voxel-by-voxel intensity change, and make biomechanical measurements. The physiologic significance of the registration-based measures of respiratory function can be established by comparing to more conventional measurements, such as nuclear medicine or contrast wash-in/wash-out studies with CT or MR. An important emerging application of these methods is the detection of pulmonary function change in subjects undergoing radiation therapy (RT) for lung cancer. During RT, treatment is commonly limited to sub-therapeutic doses due to unintended toxicity to normal lung tissue. Measurement of pulmonary function may be useful as a planning tool during RT planning, may be useful for tracking the progression of toxicity to nearby normal tissue during RT, and can be used to evaluate the effectiveness of a treatment post-therapy. This chapter reviews the basic measures to estimate regional ventilation from image registration of CT images, the comparison of them to the existing golden standard and the application in radiation therapy.

  2. Mechanical ventilation in abdominal surgery.

    Science.gov (United States)

    Futier, E; Godet, T; Millot, A; Constantin, J-M; Jaber, S

    2014-01-01

    One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEPventilator-associated lung injury in patients with healthy lungs. Stimulated by previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung protective mechanical ventilation. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery. Copyright © 2014 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

  3. Design and simulation of a hybrid ventilation system with earth-air heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Athienitis, A.K.; Zhao, M. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Roy, M. [Martin Roy and Associes Group Conseil Inc., Montreal, PQ (Canada)

    2005-07-01

    A simulation study was conducted during the design phase of a new circus building in Montreal which includes a hybrid ventilation system through which fresh air is supplied from an earth-air heat exchanger (EAHE). The EAHE has the potential to satisfy the cooling needs of the building and can also be used to preheat fresh air, thereby satisfying one-third or more of the building's heating needs. Another feature of the building is that it uses displacement ventilation by which the air is supplied at low velocities through large diffusers behind the top level seats or under the seats. In this study, computational fluid dynamics (CFD) simulations were carried out to help size the supply and return units of the heating, ventilating and air conditioning (HVAC) system, as well as the exhaust chimney. The primary objective of the CFD simulation was to determine the maximum velocity and temperature in the seated area to ensure thermal comfort. CFD simulation predictions were found to be in good agreement with preliminary measurements taken in the building. In order to monitor the operation of the system over the next year, the underground ducts were equipped with temperature sensors at several depths into the soil. The energy efficiency of the hybrid HVAC system will be assessed and the velocity and temperature distribution in the theatre will be examined under various operating and energy load conditions. 8 refs., 6 figs.

  4. 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.

  5. 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.

  6. Contaminant Distribution Around Persons in Rooms Ventilated by Displacement Ventilation

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.

    An optimal design of the ventilation system needs a proper prediction of the velocity, temperature and contaminant distribution in the room. Traditionally this is done either by the use of simplified models or by a somewhat more comprehensive CFD-simulation. Common to both methods is usually...... the lack of consideration for the persons present in the room. This paper deals with some of the effects of persons present in a displacement ventilated room, especially the effect on the contaminant distribution....

  7. Design of Energy Efficient Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    The focus in the development has for both systems been to minimise energy consumption while maintaining a comfortable and healthy indoor environment. The natural next step in this development is to develop ventilation concepts that utilises and combines the best features from each system......[Mechanical and natural ventilation] into a new type of ventilation system- Hybrid Ventilation....

  8. 21 CFR 868.5975 - Ventilator tubing.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ventilator tubing. 868.5975 Section 868.5975 Food... DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5975 Ventilator tubing. (a) Identification. Ventilator tubing is a device intended for use as a conduit for gases between a ventilator and a patient...

  9. Preoperational test report, vent building ventilation system

    International Nuclear Information System (INIS)

    Clifton, F.T.

    1997-01-01

    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

  10. 46 CFR 45.131 - Ventilators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ventilators. 45.131 Section 45.131 Shipping COAST GUARD....131 Ventilators. (a) Ventilators passing through superstructures other than enclosed superstructures must have coamings of steel or equivalent material at the freeboard deck. (b) Ventilators in position 1...

  11. 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...

  12. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system must...

  13. The role of ventilation. 2 v. Proceedings

    International Nuclear Information System (INIS)

    1994-01-01

    The 78 papers which constitute the proceedings of the conference are presented in two volumes. The papers in the first volume cover sessions dealing with the following broad topics: ventilation strategies; indoor air quality; energy impact of ventilation; building design for optimum ventilation; ventilation and energy. Volume 2 also covers ventilation strategies and ventilation and energy, and in addition: calculation, measurement and design tools; measurement and modelling. Separate abstract have been prepared for 4 papers in Volume 1 which deal with the role of ventilation in mitigating the hazard of radon in buildings. (UK)

  14. Optimal Control Design for a Solar Greenhouse

    NARCIS (Netherlands)

    Ooteghem, van R.J.C.

    2010-01-01

    Abstract: An optimal climate control has been designed for a solar greenhouse to achieve optimal crop production with sustainable instead of fossil energy. The solar greenhouse extends a conventional greenhouse with an improved roof cover, ventilation with heat recovery, a heat pump, a heat

  15. Optimal control of a solar greenhouse

    NARCIS (Netherlands)

    Ooteghem, van R.J.C.; Stigter, J.D.; Willigenburg, van L.G.; Straten, van G.

    2003-01-01

    A solar greenhouse has been designed that maximizes solar energy use and minimizes fossil energy consumption. It is based on a conventional greenhouse extended with a heat pump, a heat exchanger, an aquifer and ventilation with heat recovery. The aim is to minimize fossil energy consumption, while

  16. Newer nonconventional modes of mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Preet Mohinder Singh

    2014-01-01

    Full Text Available The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient′s demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. Various intensive care units over the world have found these modes to improve patient ventilator synchrony, decrease ventilator days and improve patient safety. The various modes discusses in this review are: Dual control modes (volume assured pressure support, volume support, Adaptive support ventilation, proportional assist ventilation, mandatory minute ventilation, Bi-level airway pressure release ventilation, (BiPAP, neurally adjusted ventilatory assist and NeoGanesh. Their working principles with their advantages and clinical limitations are discussed in brief.

  17. 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.

  18. System design package for SIMS prototype system 4, solar heating and domestic hot water

    Science.gov (United States)

    1978-01-01

    The system consisted of a modular designed prepackaged solar unit, containing solar collectors, a rock storage container, blowers, dampers, ducting, air-to-water heat exchanger, DHW preheat tank, piping, and system controls. The system was designed to be installed adjacent to a small single family dwelling. The description, performance specification, subsystem drawings, verification plan/procedure, and hazard analysis of the system were packaged for evaluation.

  19. Pulsed ventilation in mines. II

    Energy Technology Data Exchange (ETDEWEB)

    Krause, D

    1975-06-01

    Using test results, an attempt is made to determine the form of the free jet and to derive design data for pulsed fans. The most suitable placing of these fans for the ventilation of headings is discussed.

  20. ENERGY STAR Certified Ventilating Fans

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Ventilating Fans that are effective as of...

  1. Two-story residence with solar heating--Newman, Georgia

    Science.gov (United States)

    1981-01-01

    Report evaluates performance of warm-air collector system for 11 month period and provides operation and maintenance information. System consists of 14 warm air collectors, rock-storage bin, air handler, heat exchangers, hot-water preheat tank, associated controls, plumbing, and air ducting. Average building temperature was maintained at 72 F (22 C); solar equipment provided 47 percent of space-heating requirement.

  2. TS LOOP ALCOVE VENTILATION ANALYSIS

    International Nuclear Information System (INIS)

    T.M. Lahnalampi

    2000-01-01

    The scope of this analysis is to examine the existing, constructor installed, physical ventilation installations located in each of the Exploratory Studies Facility (ESF) Topopah Springs (TS) Loop Alcoves No.1, No.2, No.3, No.4, No.6, and No.7. Alcove No.5 is excluded from the scope of this analysis since it is an A/E design system. Each ventilation installation will be analyzed for the purpose of determining if requirements for acceptance into the A/E design technical baseline have been met. The ventilation installations will be evaluated using Occupational Safety and Health Administration (OSHA) standards and Exploratory Studies Facility Design Requirements (ESFDR) (YMP 1997) requirements. The end product will be a technical analysis that will define ventilation installation compliance issues, any outstanding field changes, and use-as-is design deviations that are required to bring the ventilation installations into compliance with requirements for acceptance into the A/E design technical baseline. The analysis will provide guidance for alcove ventilation component design modifications to be developed to correct any deficient components that do not meet minimum requirements and standards

  3. Ventilation Model and Analysis Report

    International Nuclear Information System (INIS)

    Chipman, V.

    2003-01-01

    This model and analysis report develops, validates, and implements a conceptual model for heat transfer in and around a ventilated emplacement drift. This conceptual model includes thermal radiation between the waste package and the drift wall, convection from the waste package and drift wall surfaces into the flowing air, and conduction in the surrounding host rock. These heat transfer processes are coupled and vary both temporally and spatially, so numerical and analytical methods are used to implement the mathematical equations which describe the conceptual model. These numerical and analytical methods predict the transient response of the system, at the drift scale, in terms of spatially varying temperatures and ventilation efficiencies. The ventilation efficiency describes the effectiveness of the ventilation process in removing radionuclide decay heat from the drift environment. An alternative conceptual model is also developed which evaluates the influence of water and water vapor mass transport on the ventilation efficiency. These effects are described using analytical methods which bound the contribution of latent heat to the system, quantify the effects of varying degrees of host rock saturation (and hence host rock thermal conductivity) on the ventilation efficiency, and evaluate the effects of vapor and enhanced vapor diffusion on the host rock thermal conductivity

  4. Mechanical ventilation for severe asthma.

    Science.gov (United States)

    Leatherman, James

    2015-06-01

    Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting.

  5. Energy Use Consequences of Ventilating a Net-Zero Energy House

    Science.gov (United States)

    Ng, Lisa C.; Payne, W. Vance

    2016-01-01

    A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved

  6. Energy Use Consequences of Ventilating a Net-Zero Energy House.

    Science.gov (United States)

    Ng, Lisa C; Payne, W Vance

    2016-03-05

    A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved

  7. Solar project description for Moulder Corporation single family residence, Greenwood, Indiana

    Science.gov (United States)

    1980-07-01

    The system is designed to provide solar energy for space heating and domestic hot water heating. Solar energy is used for space heating the home and preheating domestic hot water (DHW). The solar energy system has an array of flat plate collectors with a gross area of 704 square feet. The array faces 5.5 degrees west of south at an angle of 45 degrees to the horizontal. Air is the transfer medium that delivers solar energy from the collector array to storage, space heating and hot water loads. Solar energy is stored underground in 945 cubic foot bin containing 81,000 pounds of crushed rock. The bin has 8 inch concrete block walls and the insulation on the exterior is sprayed urethane. Preheated city water is stored in an 80 gallon preheat tank, which is inside the storage bin and is supplied, on demand, to a conventional 52 gallon DHW tank. When solar energy is insufficient to satisfy the space heating load, a conventional electric furnace provides the auxiliary energy for space heating.

  8. Solar energy system performance evaluation report for IBM System 4 at Clinton, Mississippi

    Science.gov (United States)

    1980-07-01

    The IBM System 4 Solar Energy System is described and evaluated. The system was designed to provide 35 percent of the space heating and 63 percent of the domestic hot water preheating for a single family residence located within the United States. The system consists of 259 square feet of flat plate air collectors, a rock thermal storage containing 5 1/2 ton of rock, heat exchangers, blowers, a 52 gallon preheat tank, controls, and associated plumbing. In general, the performance of the system did not meet design expectations, since the overall design solar fraction was 48 percent and the measured value was 32 percent. Although the measured space heating solar fraction at 32 percent did agree favorably with the design space heating solar fraction at 35 percent, the hot water measured solar fraction at 33 percent did not agree favorably with the design hot water solar fraction of 63 percent. In particular collector array air leakage, dust covered collectors, abnormal hot water demand, and the preheat tank by pass valve problem are main reasons for the lower performance.

  9. Impact of Fire Ventilation on General Ventilation in the Building

    Science.gov (United States)

    Zender-Świercz, Ewa; Telejko, Marek

    2017-10-01

    The fire of building is a threat to its users. The biggest threat is generation, during lifetime of fire, hot gases and smoke. The purpose of quick and efficient evacuation from the area covered by the fire, at first step the escape routes have to be secured from smokiness. The smoke ventilation systems are used for this purpose. The proper design and execution of smoke ventilation is important not only because of the safety, but also of the maintenance of comfort in the building at a time when there is no fire. The manuscript presents the effect of incorrectly realized smoke ventilation in the stairwell of the medium building. The analysis shows that the flaps of smoke ventilation located in the stairwell may have a significant impact on the proper functioning of mechanical ventilation in the period when there is no fire. The improperly installed or incorrect insulated components cause perturbation of air flow and they change pressure distribution in the building. The conclusion of the analysis is the need to include the entire technical equipment of the building during the design and realization of its individual elements. The impact of various installations at each other is very important, and the omission of any of them can cause disturbances in the proper work of another.

  10. Surface Characteristics of Machined NiTi Shape Memory Alloy: The Effects of Cryogenic Cooling and Preheating Conditions

    Science.gov (United States)

    Kaynak, Y.; Huang, B.; Karaca, H. E.; Jawahir, I. S.

    2017-07-01

    This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish ( A f) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.

  11. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-Ray Preheat

    International Nuclear Information System (INIS)

    Colvin, Jeffrey D.; Kalantar, Daniel H.

    2006-01-01

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<1013 W/cm2, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flash-coating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

  12. Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat

    International Nuclear Information System (INIS)

    Colvin, J D; Kalantar, D H

    2005-01-01

    To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, 13 W/cm 2 , compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe

  13. X-ray emission, ablation pressure, and preheating for foils irradiated at 0. 26. mu. m wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

    1985-11-01

    The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 ..mu..m laser at intensities approx.10/sup 15/ W cm/sup -2/ are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 ..mu..m), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant.

  14. X-ray emission, ablation pressure, and preheating for foils irradiated at 0.26 μm wavelength

    International Nuclear Information System (INIS)

    Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

    1985-01-01

    The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 μm laser at intensities approx.10 15 W cm -2 are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 μm), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant

  15. 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.

  16. Modeling of crude oil fouling in preheat exchangers of refinery distillation units

    Energy Technology Data Exchange (ETDEWEB)

    Jafari Nasr, Mohammad Reza; Majidi Givi, Mehdi [National Petrochemical Research and Technology Company (NPC-RT), P.O. Box 14385, Tehran (Iran)

    2006-10-15

    The aim of this paper is to propose a new model for crude oil fouling in preheat exchangers of crude distillation units. The experimental results of Australian light crude oil with the tube side surface temperature between 200 and 260{sup o}C and fluid velocity ranged 0.25-0.4m/s were used [Z. Saleh, R. Sheikholeslami, A.P. Watkinson, Heat exchanger fouling by a light australian crude oil, in: Heat Exchanger Fouling and Cleaning Fundamentals and Applications, Santa Fe, 2003]. The amount of activation energy depends on the surface temperature has been calculated. A new model including a term for fouling formation and a term for fouling removal due to chemical and tube wall shear stress was proposed, respectively. The main superiority of the model are independent to Pr number, thermal fouling removal and determination of {beta} based on experimental tests. Finally using the proposed model the fouling rate of Australian light crude oil has been calculated and the threshold curves to identify fouling and no fouling formation zones have been drawn. (author)

  17. Effect of substrate preheating temperature and coating thickness on residual stress in plasma sprayed hydroxyapatite coating

    International Nuclear Information System (INIS)

    Tang, Dapei

    2015-01-01

    A thermal-mechanical coupling model was developed based on thermal-elastic- plastic theory according the special process of plasma spraying Hydroxyapatite (HA) coating upon Ti-6Al-4V substrate. On the one hand, the classical Fourier transient heat conduction equation was modified by introducing the effect item of deformation on temperature, on the other hand, the Johnson-Cook model, suitable for high temperature and high strain rate conditions, was used as constitutive equation after considering temperature softening effect, strain hardening effect and strain rate reinforcement effect. Based on the above coupling model, the residual stress field within the HA coating was simulated by using finite element method (FEM). Meanwhile, the substrate preheating temperature and coating thickness on the influence of residual stress components were calculated, respectively. The failure modes of coating were also preliminary analyzed. In addition, in order to verify the reliability of calculation, the material removal measurement technique was applied to determine the residual stress of HA coating near the interface. Some important conclusions are obtained. (paper)

  18. Synthesis and physical properties of zinc-oxide textured films by using a filtered preheated hydrothermal

    International Nuclear Information System (INIS)

    Qiu, Jijun; Shin, Dongmyeong; He, Weizhen; Kim, Hyungkook; Hwang, Yoonhwae; Li, Xiaomin; Gao, Xiangdong

    2014-01-01

    Axially (c-axis)-oriented ZnO thick films with a ∼8.1 μm thickness were fabricated on ZnO seed layer coated substrates by using a filtered preheated hydrothermal solution. The thick films composed of single-crystal ZnO microrods with various diameters were formed by coalescing each nanorod together along their side surfaces. From the X-ray diffraction result a biaxial stress exists was found to exist in the as-grown thick films, and the stress gradually increased with increasing annealing temperatures from 200 to 550 .deg. C due to a degradation in the crystalline quality. The biaxial stress is responsible for the red-shift of the optical band gap of the ZnO thick films. Photoluminescence and Hall results revealed that the optical and the electrical properties of the thick films were degenerated after high-temperature annealing (> 200 .deg. C), which was due to the introduction of point defects, such as oxygen interstitials and zinc vacancies.

  19. Ways to achieve optimum utilization of waste gas heat in cement kiln plants with cyclone preheaters

    Energy Technology Data Exchange (ETDEWEB)

    Steinbiss, E

    1986-02-01

    Kiln exit gases and the exhaust gases from clinker coolers often cannot be fully utilized in drying plants. In such cases a part of the heat content of the gases should be utilized for water heating. In addition, it is possible to utilize the waste gas heat in conventional steam boilers, with which, depending on design, it is possible to generate electricity at a rate of between 10-30 kWh/t (net output). A new and promising method of utilization of waste gas heat is provided by precalcining systems with bypass, in which up to 100% of the kiln exit gases can be economically bypassed and be utilized in a steam boiler, without requiring any cooling. A development project, already started, gives information on the operational behaviour of such a plant and on the maximum energy recoverable. Alternatively, the bypass gases may, after partial cooling with air or preheater exit gas, be dedusted and then utilized in a grinding/drying plant. Furthermore, they can be used in the cement grinding process for the drying of wet granulated blastfurnace slag or other materials. For this it is not necessary to dedust the bypass gases.

  20. Synthesis and physical properties of zinc-oxide textured films by using a filtered preheated hydrothermal

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Jijun [Pusan National University, Busan (Korea, Republic of); Shin, Dongmyeong; He, Weizhen; Kim, Hyungkook; Hwang, Yoonhwae [Pusan National University, Miryang (Korea, Republic of); Li, Xiaomin; Gao, Xiangdong [Chinese Academy of Sciences, Shanghai (China)

    2014-11-15

    Axially (c-axis)-oriented ZnO thick films with a ∼8.1 μm thickness were fabricated on ZnO seed layer coated substrates by using a filtered preheated hydrothermal solution. The thick films composed of single-crystal ZnO microrods with various diameters were formed by coalescing each nanorod together along their side surfaces. From the X-ray diffraction result a biaxial stress exists was found to exist in the as-grown thick films, and the stress gradually increased with increasing annealing temperatures from 200 to 550 .deg. C due to a degradation in the crystalline quality. The biaxial stress is responsible for the red-shift of the optical band gap of the ZnO thick films. Photoluminescence and Hall results revealed that the optical and the electrical properties of the thick films were degenerated after high-temperature annealing (> 200 .deg. C), which was due to the introduction of point defects, such as oxygen interstitials and zinc vacancies.

  1. Combustion analysis of preheated crude sunflower oil in an IDI diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Canakci, Mustafa; Ozsezen, Ahmet Necati; Turkcan, Ali [Department of Mechanical Education, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey)

    2009-05-15

    In this study, preheated crude sunflower oil (PCSO) was tested for combustion and emission properties against petroleum based diesel fuel (PBDF) in a naturally aspirated, indirect injection (IDI) engine. The cylinder gas pressure and heat release curves for PCSO at 75 C were similar to those of PBDF. The ignition delays for the PCSO were longer and the start of injection timing was earlier than for PBDF. The difference in the average brake torque was a decrease of 1.36% for PCSO though this was statistically insignificant. The brake specific fuel consumption increased by almost 5% more or less in proportion to the difference in calorific value, so that the 1.06% increase in thermal efficiency was again statistically insignificant. The emission test results showed that the decreases in CO{sub 2} emissions and smoke opacity 2.05% and 4.66%, respectively; however, this was not statistically significant, though in line with the apparent increase in thermal efficiency. There was a significant 34% improvement in the emissions of unburnt hydrocarbons. Carbon monoxide increased by 1.77% again the result was not statistically significant given the small number of repeat tests. The use of PCSO does not have any negative effects on the engine performance and emissions in short duration engine testing. (author)

  2. Useful work and the thermal efficiency in the ideal Lenolr cycle with regenerative preheating

    Science.gov (United States)

    Georgiou, Demos P.

    2000-11-01

    In the existing thermal engine concepts negative work transfer (usually needed to drive a compression process) is supplied by the work produced by the engine itself. The remaining difference (i.e., the net work transfer) becomes the useful work, since it is available for external consumption. The thermal efficiency is the parameter that compares this against the heat input into the system. It forms the main optimization parameter in any engine design. The objective of the present study is to show that for the case of the Lenoir cycle with regenerative preheating the entire positive work is available for external consumption, since the negative (i.e., the compression) work is supplied by the atmospheric air. Not only this, but, during the compression process and due to the pressure difference across the two sides of the moving piston, an additional (useful) work transfer may be generated. Thus, the proposed power plant may be considered as a combination of a thermal engine and a wind turbine. In the ideal cycle limit (at least), the total amount of useful work exceeds the heat entering the system. This leads to the definition of a new parameter for the efficiency (called the technical efficiency), which compares the combined positive work transfer (i.e., the useful one) against the heat entering the system and which may exceed the 100% level.

  3. 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.

  4. Contaminants in ventilated filling boxes

    Science.gov (United States)

    Bolster, D. T.; Linden, P. F.

    While energy efficiency is important, the adoption of energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. Many low-energy systems, such as displacement or natural ventilation, rely on temperature stratification within the interior environment, always extracting the warmest air from the top of the room. Understanding buoyancy-driven convection in a confined ventilated space is key to understanding the flow that develops with many of these modern low-energy ventilation schemes. In this work we study the transport of an initially uniformly distributed passive contaminant in a displacement-ventilated space. Representing a heat source as an ideal sourced of buoyancy, analytical and numerical models are developed that allow us to compare the average efficiency of contaminant removal between traditional mixing and modern low-energy systems. A set of small-scale analogue laboratory experiments was also conducted to further validate our analytical and numerical solutions.We find that on average traditional and low-energy ventilation methods are similar with regard to pollutant flushing efficiency. This is because the concentration being extracted from the system at any given time is approximately the same for both systems. However, very different vertical concentration gradients exist. For the low-energy system, a peak in contaminant concentration occurs at the temperature interface that is established within the space. This interface is typically designed to sit at some intermediate height in the space. Since this peak does not coincide with the extraction point, displacement ventilation does not offer the same benefits for pollutant flushing as it does for buoyancy removal.

  5. Establishment of welding process without PWHT and preheating in SGV480 plate for nuclear reactor containment vessel

    International Nuclear Information System (INIS)

    Watanabe, Nozomu; Higashikubo, Tomohiro; Nagamura, Takafumi; Yoshimoto Kentaro

    2000-01-01

    Ordinances of Japan's Ministry of International Trade and Industry provide that welded joints more than 38 mm thick used in nuclear reactor containment vessels undergo Post Weld Heat Treatment (PWHT). PWHT is difficult to apply in the field, however. We made SGV480 plate tougher and more weldable by using a Thermo-Mechanical Control Process (TMCP) in rolling. Such plate can be used without PWHT or preheating up to 55 mm thick at lowest service temperature -19degC. (author)

  6. Trigger performance of mid-level ICU mechanical ventilators during assisted ventilation: a bench study.

    Science.gov (United States)

    Ferreira, Juliana C; Chipman, Daniel W; Kacmarek, Robert M

    2008-09-01

    To compare the triggering performance of mid-level ICU mechanical ventilators with a standard ICU mechanical ventilator. Experimental bench study. The respiratory care laboratory of a university-affiliated teaching hospital. A computerized mechanical lung model, the IngMar ASL5000. Ten mid-level ICU ventilators were compared to an ICU ventilator at two levels of lung model effort, three combinations of respiratory mechanics (normal, COPD and ARDS) and two modes of ventilation, volume and pressure assist/control. A total of 12 conditions were compared. Performance varied widely among ventilators. Mean inspiratory trigger time was ventilators. The mean inspiratory delay time (time from initiation of the breath to return of airway pressure to baseline) was longer than that for the ICU ventilator for all tested ventilators except one. The pressure drop during triggering (Ptrig) was comparable with that of the ICU ventilator for only two ventilators. Expiratory Settling Time (time for pressure to return to baseline) had the greatest variability among ventilators. Triggering differences among these mid-level ICU ventilators and with the ICU ventilator were identified. Some of these ventilators had a much poorer triggering response with high inspiratory effort than the ICU ventilator. These ventilators do not perform as well as ICU ventilators in patients with high ventilatory demand.

  7. Effect of pre-heating on the chemical oxidation efficiency: implications for the PAH availability measurement in contaminated soils.

    Science.gov (United States)

    Biache, Coralie; Lorgeoux, Catherine; Andriatsihoarana, Sitraka; Colombano, Stéfan; Faure, Pierre

    2015-04-09

    Three chemical oxidation treatments (KMnO4, H2O2 and Fenton-like) were applied on three PAH-contaminated soils presenting different properties to determine the potential use of these treatments to evaluate the available PAH fraction. In order to increase the available fraction, a pre-heating (100 °C under N2 for one week) was also applied on the samples prior oxidant addition. PAH and extractable organic matter contents were determined before and after treatment applications. KMnO4 was efficient to degrade PAHs in all the soil samples and the pre-heating slightly improved its efficiency. H2O2 and Fenton-like treatments presented low efficiency to degrade PAH in the soil presenting poor PAH availability, however, the PAH degradation rates were improved with the pre-heating. Consequently H2O2-based treatments (including Fenton-like) are highly sensitive to contaminant availability and seem to be valid methods to estimate the available PAH fraction in contaminated soils. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Effect of bond coat and preheat on the microstructure, hardness, and porosity of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermally sprayed coatings are used to improve the surface properties of tool steel materials. Bond coatings are commonly used as intermediate layers deposited on steel substrates (i.e. H13 tool steel) before the top coat is applied in order to enhance a number of critical performance criteria including adhesion of a barrier coating, limiting atomic migration of the base metal, and corrosion resistance. This paper presents the experimental results regarding the effect of nickel bond coat and preheats temperatures (i.e. 200°C, 300°C and 400°C) on microstructure, hardness, and porosity of tungsten carbide coatings sprayed by flame thermal coating. Micro-hardness, porosity and microstructure of tungsten carbide coatings are evaluated by using micro-hardness testing, optical microscopy, scanning electron microscopy, and X-ray diffraction. The results show that nickel bond coatings reduce the susceptibility of micro crack formation at the bonding area interfaces. The percentage of porosity level on the tungsten carbide coatings with nickel bond coat decreases from 5.36 % to 2.78% with the increase of preheat temperature of the steel substrate of H13 from 200°C to 400°C. The optimum hardness of tungsten carbide coatings is 1717 HVN in average resulted from the preheat temperature of 300°C.

  9. Influence of preheating on API 5L-X80 pipeline joint welding with self shielded flux-cored wire

    International Nuclear Information System (INIS)

    Cooper, R.; Silva, J. H. F.; Trevisan, R. E.

    2004-01-01

    The present work refers to the characterization of API 5L-X80 pipeline joints welded with self-shielded flux cored wire. This process was evaluated under preheating conditions, with an uniform and steady heat input. All joints were welded in flat position (1G), with the pipe turning and the torch still. Tube dimensions were 762 mm in external diameter and 16 mm in thickness. Welds were applied on single V-groove, with six weld beads, along with three levels of preheating temperatures (room temperature, 100 degree centigree, 160 degree centigree). These temperatures were maintained as inter pass temperature. The filler metal E71T8-K6 with mechanical properties different from parent metal was used in under matched conditions. The weld characterization is presented according to the mechanical test results of tensile strength, hardness and impact test. The mechanical tests were conducted according to API 1104, AWS and ASTM standards. API 1104 and API 51 were used as screening criteria. According to the results obtained, it was possible to remark that it is appropriate to weld API 5L-X80 steel ducts with Self-shielded Flux Cored wires, in conformance to the API standards and no preheat temperature is necessary. (Author) 22 refs

  10. Tidal ventilation distribution during pressure-controlled ventilation and pressure support ventilation in post-cardiac surgery patients.

    Science.gov (United States)

    Blankman, P; VAN DER Kreeft, S M; Gommers, D

    2014-09-01

    Inhomogeneous ventilation is an important contributor to ventilator-induced lung injury. Therefore, this study examines homogeneity of lung ventilation by means of electrical impedance tomography (EIT) measurements during pressure-controlled ventilation (PCV) and pressure support ventilation (PSV) using the same ventilation pressures. Twenty mechanically ventilated patients were studied after cardiac surgery. On arrival at the intensive care unit, ventilation distribution was measured with EIT just above the diaphragm for 15 min. After awakening, PCV was switched to PSV and EIT measurements were again recorded. Tidal impedance variation, a measure of tidal volume, increased during PSV compared with PCV, despite using the same ventilation pressures (P = 0.045). The distribution of tidal ventilation to the dependent lung region was more pronounced during PSV compared with PCV, especially during the first half of the inspiration. An even distribution of tidal ventilation between the dependent and non-dependent lung regions was seen during PCV at lower tidal volumes (tidal volumes (≥ 8 ml/kg). In addition, the distribution of tidal ventilation was predominantly distributed to the dependent lung during PSV at low tidal volumes. In post-cardiac surgery patients, PSV showed improved ventilation of the dependent lung region due to the contribution of the diaphragm activity, which is even more pronounced during lower assist levels. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  11. Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF.

    Science.gov (United States)

    Döppner, T; Dewald, E L; Divol, L; Thomas, C A; Burns, S; Celliers, P M; Izumi, N; Kline, J L; LaCaille, G; McNaney, J M; Prasad, R R; Robey, H F; Glenzer, S H; Landen, O L

    2012-10-01

    We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.

  12. Residential ventilation standards scoping study

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  13. 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...

  14. Demand controlled ventilation in a bathroom

    DEFF Research Database (Denmark)

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

    2008-01-01

    consumption during periods where the demand for ventilation is low and poor indoor climate during periods where the demand for ventilation is high. Controlling the ventilation rate by demand can improve the energy performance of the ventilation system and the indoor climate. This paper compares the indoor...... climate and energy consumption of a Constant Air Volume (CAV) system and a Demand Controlled Ventilation (DCV) system for two different bathroom designs. The air change rate of the CAV system corresponded to 0.5h-1. The ventilation rate of the DCV system was controlled by occupancy and by the relative...

  15. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    Energy Technology Data Exchange (ETDEWEB)

    Šturm, Roman, E-mail: roman.sturm@fs.uni-lj.si [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Štefanikova, Maria [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Steiner Petrovič, Darja [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia)

    2015-01-15

    Graphical abstract: - Highlights: • Heat-treatment protocol for laser surface melting of cold-work tool steel is proposed. • The laser melted steel surface is hardened, and morphologically modified. • The pre-heating of substrate creates a crack-and pore-free steel surface. • The optimum pre-heating temperature is determined to be 350 °C. • Using pre-heating the quantity of retained austenite is reduced. - Abstract: In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides.

  16. Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

    Science.gov (United States)

    1980-01-01

    The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

  17. Solar heating and domestic hot water system installed at Kansas City, Fire Stations, Kansas City, Missouri

    Science.gov (United States)

    1980-07-01

    The solar system was designed to provide 47 percent of the space heating, 8,800 square feet area and 75 percent of the domestic hot water (DHW) load. The solar system consists of 2,808 square feet of Solaron, model 2001, air, flat plate collector subsystem, a concrete box storage subsystem which contains 1,428 cubic feet of 0.5 inch diameter pebbles weighing 71.5 tons, a DHW preheat tank, blowers, pumps, heat exchangers, air ducting, controls and associated plumbing. Two 120 gallon electric DHW heaters supply domestic hot water which is preheated by the solar system. Auxiliary space heating is provided by three electric heat pumps with electric resistance heaters and four 30 kilowatt electric unit heaters. There are six modes of system operation.

  18. Energy, exergy, environmental and economic analysis of industrial fired heaters based on heat recovery and preheating techniques

    International Nuclear Information System (INIS)

    Shekarchian, M.; Zarifi, F.; Moghavvemi, M.; Motasemi, F.; Mahlia, T.M.I.

    2013-01-01

    Highlights: • 4-E analysis of a typical industrial grade fired heater unit is studied. • This analysis is accomplished for the first time in this study. • Heat recovery and air preheating lead to substantial reduction in the fuel consumption. • The company’s current costs are tremendously reduced by these methods. • The methods lead to mitigation in GHG emission and to reduction in the associated taxes. - Abstract: Fired heaters are ubiquitous in both the petroleum and petrochemical industries, due to it being vital in their day to day operations. They form major components in petroleum refineries, petrochemical facilities, and processing units. This study was commissioned in order to analyze the economic benefits of incorporating both heat recovery and air preheating methods into the existing fired heater units. Four fired heater units were analyzed from the energy and environmental point of views. Moreover, the second law efficiency and the rate of irreversibility were also analyzed via the exergy analysis. Both analyses was indicative of the fact that the heat recovery process enhances both the first and second law efficiencies while simultaneously assisting in the production of high and low pressure water steam. The implementation and usage of the process improves the thermal and exergy efficiencies from 63.4% to 71.7% and 49.4%, to 54.8%, respectively. Additionally, the heat recovery and air preheating methods leads to a substantial reduction in fuel consumption, in the realm of up to 7.4%, while also simultaneously decreasing heat loss and the irreversibility of the unit. Nevertheless, the results of the economic analysis posits that although utilizing an air preheater unit enhances the thermal performance of the system, due to the air preheater’s capital and maintenance costs, incorporating an air preheater unit to an existing fired heater is not economically justifiable. Furthermore, the results of the sensitivity analysis and payback period

  19. Air ventilation/controlling facility

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kazuhiro; Kinoshita, Shoichiro

    1997-12-12

    When all electricity supply from the outside of a power plant are lost, a power generator directly connected to an emergency steam turbine which is driven by steams introduced from a nuclear reactor is driven to supply electricity required in the power plant. Cool water prepared by a refrigerator is used as cooling water in an air ventilation/controlling facility of a room equipped with the power generating facility. As the refrigerator, a refrigerator of an existent emergency air cooling water system for an auxiliary air ventilation/controlling equipment is used. This can extend the period of time till the temperature of the room where the power generator is disposed exceeds the temperature range capable of keeping the integrity of the power generator even when all the AC power supply are lost to inactivate the function of the air ventilation/controlling system. (I.S.)

  20. Job creation potential of solar

    International Nuclear Information System (INIS)

    McMonagle, R.

    2005-01-01

    This document defines the size of the job market within Canada's solar industry and presents a preliminary forecast of the employment opportunities through to 2025. The issue of job potential within Canada's solar technologies is complicated by the wide range of different fields and technologies within the solar industry. The largest energy generator of the solar technologies is passive solar, but the jobs in this sector are generally in the construction trades and window manufacturers. The Canadian Solar Industries Association estimates that there are about 360 to 500 firms in Canada with the primary business of solar technologies, employing between 900 to 1,200 employees. However, most solar manufacturing jobs in Canada are for products exports as demonstrated by the 5 main solar manufacturers in Canada who estimate that 50 to 95 per cent of their products are exported. The main reason for their high export ratio is the lack of a Canadian market for their products. The 3 categories of job classifications within the solar industry include manufacturing, installation, and operations and maintenance. The indirect jobs include photovoltaic system hardware, solar hot water heating, solar air ventilation, and glass/metal framing. 17 refs., 3 tabs., 2 figs

  1. Solar heating of the produced water of petroleum; Aquecimento solar da agua produzida de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Rogerio Pitanga; Chiavone-Filho, Osvaldo; Bezerra, Magna A. Santos; Melo, Josette Lourdes Sousa de; Oliveira, Jackson Araujo de; Ramos, Rafael E. Moura [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Schuhli, Juliana Bregenski; Andrade, Vivian Tavares de [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    In this work, experimental data of solar heating for common water and saline solution were measured. The solar heater is formed by a flat-plane collector and a thermal reservoir ('boiler'). The objective is to quantify the variation of fluids' temperature, and correlate it to environment variables, especially solar irradiation. Thereby, it is possible to estimate the solar heating of produced water of petroleum. The solar heater is part of a system of treatment of produced water, and its function is to pre-heat the fluid that enters into the solar distiller, increasing the productivity of distilled water. A saline solution that represents produced water was used in the experiments, using sodium chloride (1000 ppm). The experimental data demonstrates that the solar heater is capable to heat the fluid to temperatures close to 70 deg C, reaching temperatures close to 50 deg C even during cloudy days with low solar radiation. Furthermore, the solar collector energy system provides a higher rate of heating and trough of the thermal reservoir the temperature can remain longer. These are important aspects to the integration with solar distillation. (author)

  2. Solar heating of the produced water of petroleum; Aquecimento solar da agua produzida de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Rogerio Pitanga; Chiavone-Filho, Osvaldo; Bezerra, Magna A. Santos; Melo, Josette Lourdes Sousa de; Oliveira, Jackson Araujo de; Ramos, Rafael E. Moura [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Schuhli, Juliana Bregenski; Andrade, Vivian Tavares de [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    In this work, experimental data of solar heating for common water and saline solution were measured. The solar heater is formed by a flat-plane collector and a thermal reservoir ('boiler'). The objective is to quantify the variation of fluids' temperature, and correlate it to environment variables, especially solar irradiation. Thereby, it is possible to estimate the solar heating of produced water of petroleum. The solar heater is part of a system of treatment of produced water, and its function is to pre-heat the fluid that enters into the solar distiller, increasing the productivity of distilled water. A saline solution that represents produced water was used in the experiments, using sodium chloride (1000 ppm). The experimental data demonstrates that the solar heater is capable to heat the fluid to temperatures close to 70 deg C, reaching temperatures close to 50 deg C even during cloudy days with low solar radiation. Furthermore, the solar collector energy system provides a higher rate of heating and trough of the thermal reservoir the temperature can remain longer. These are important aspects to the integration with solar distillation. (author)

  3. [Pressure support ventilation and proportional assist ventilation during weaning from mechanical ventilation].

    Science.gov (United States)

    Aguirre-Bermeo, H; Bottiroli, M; Italiano, S; Roche-Campo, F; Santos, J A; Alonso, M; Mancebo, J

    2014-01-01

    To compare tolerance, duration of mechanical ventilation (MV) and clinical outcomes during weaning from MV in patients subjected to either pressure support ventilation (PSV) or proportional assist ventilation (PAV). A prospective, observational study was carried out. Intensive Care Unit. A total of 40 consecutive subjects were allocated to either the PSV or the PAV group until each group contained 20 patients. Patients were included in the study when they met the criteria to begin weaning and the attending physician decided to initiate the weaning process. The physician selected the modality and set the ventilatory parameters. None. Demographic data, respiratory mechanics, ventilatory parameters, duration of MV, and clinical outcomes (reintubation, tracheostomy, mortality). Baseline characteristics were similar in both groups. No significant differences were observed between the PSV and PAV groups in terms of the total duration of MV (10 [5-18] vs. 9 [7-19] days; P=.85), reintubation (5 [31%] vs. 3 [19%]; P=.69), or mortality (4 [20%] vs. 5 [25%] deaths; P=1). Eight patients (40%) in the PSV group and 6 patients (30%) in the PAV group (P=.74) required a return to volume assist-control ventilation due to clinical deterioration. Tolerance, duration of MV and clinical outcomes during weaning from mechanical ventilation were similar in PSV and PAV. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  4. Membrane modules for building ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Kistler, K.R.; Cussler, E.L.

    2002-01-01

    Hollow fibre and flat sheet membranes with an interfacially polymerized coating of polyamide have a permeance for water vapour of about 0.16 m sec{sup -1}. These membranes can serve as a basis for building ventilation which provides fresh air while recovering about 70% of the specific heat and 60% of the latent heat. Because these membranes are selective for water vapour, the air is exhausted with internal pollutants like carbon monoxide, formaldehyde, and radon. The expense of the ventilator should be recovered in reduced heating costs in about three years. (Author)

  5. Limiting volume with modern ventilators.

    Science.gov (United States)

    Wing, Thomas J; Haan, Lutana; Ashworth, Lonny J; Anderson, Jeff

    2015-06-01

    The acute respiratory distress syndrome (ARDS) network low tidal-volume study comparing tidal volumes of 12 ml/kg versus 6 ml/kg was published in 2000. The study was stopped early as data revealed a 22% relative reduction in mortality rate when using 6 ml/kg tidal volume. The current generation of critical care ventilators allows the tidal volume to be set during volume-targeted, assist/control (volume A/C); however, some ventilators include options that may prevent the tidal volume from being controlled. The purpose of this bench study was to evaluate the delivered tidal volume, when these options are active, in a spontaneously breathing lung model using an electronic breathing simulator. Four ventilators were evaluated: CareFusion AVEA (AVEA), Dräger Evita® XL (Evita XL), Covidien Puritan Bennett® 840(TM) (PB 840), and Maquet SERVO-i (SERVO-i). Each ventilator was connected to the Hans Rudolph Electronic Breathing Simulator at an amplitude of 0 cm H2O and then 10 cm H2O. All four ventilators were set to deliver volume A/C, tidal volume 400 ml, respiratory rate 20 bpm, positive end-expiratory pressure 5 cm H2O, peak flowrate 60 L/min. The displayed tidal volume was recorded for each ventilator at the above settings with additional options OFF and then ON. The AVEA has two options in volume A/C: demand breaths and V-sync. When activated, these options allow the patient to exceed the set tidal volume. When using the Evita XL, the option AutoFlow can be turned ON or OFF, and when this option is ON, the tidal volume may vary. The PB 840 does not have any additional options that affect volume delivery, and it maintains the set tidal volume regardless of patient effort. The SERVO-i's demand valve allows additional flow if the patient's inspiratory flowrate exceeds the set flowrate, increasing the delivered tidal volume; this option can be turned OFF with the latest software upgrade. Modern ventilators have an increasing number of optional settings. These settings may

  6. Performance and emission study of preheated Jatropha oil on medium capacity diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Bhupendra Singh; Du Jun, Yong; Lee, Kum Bae [Division of Automobile and Mechanical Engineering, Kongju National University (Korea); Kumar, Naveen [Department of Mechanical Engineering, Delhi Technological University, Bawana Road, Delhi 42 (India)

    2010-06-15

    Diesel engines have proved their utility in transport, agriculture and power sector. Environmental norms and scared fossil fuel have attracted the attention to switch the energy demand to alternative energy source. Oil derived from Jatropha curcas plant has been considered as a sustainable substitute to diesel fuel. However, use of straight vegetable oil has encountered problem due to its high viscosity. The aim of present work is to reduce the viscosity of oil by heating from exhaust gases before fed to the engine, the study of effects of FIT (fuel inlet temperature) on engine performance and emissions using a dual fuel engine test rig with an appropriately designed shell and tube heat exchanger (with exhaust bypass arrangement). Heat exchanger was operated in such a way that it could give desired FIT. Results show that BTE (brake thermal efficiency) of engine was lower and BSEC (brake specific energy consumption) was higher when the engine was fueled with Jatropha oil as compared to diesel fuel. Increase in fuel inlet temperature resulted in increase of BTE and reduction in BSEC. Emissions of NO{sub x} from Jatropha oil during the experimental range were lower than diesel fuel and it increases with increase in FIT. CO (carbon monoxide), HC (hydrocarbon), CO{sub 2} (carbon dioxide) emissions from Jatropha oil were found higher than diesel fuel. However, with increase in FIT, a downward trend was observed. Thus, by using heat exchanger preheated Jatropha oil can be a good substitute fuel for diesel engine in the near future. Optimal fuel inlet temperature was found to be 80 C considering the BTE, BSEC and gaseous emissions. (author)

  7. Seawater feed reverse osmosis preheating appraisal, Part I: leading element performance

    International Nuclear Information System (INIS)

    Karameldin, A.; Saadawy, M.S.

    2006-01-01

    This paper is concerned with the seawater reverse osmosis preheating process, and presents a parametric study of the process. The basic transport equations describing the leading element are exhibited and appraised. The leading element, which governs the whole system performance, is studied and analysed. The incorporated and investigated operating parameters are the feed pressure and the temperature for different feed salt concentrations. In addition, different feed flow rates, effects on permeate flux and permeator salt rejection, together with the permeator recovery, are studied. A seawater membrane of a well-known data, for instance FT30SW380HR, is used to perform the study. The membrane water permeability coefficient K w is determined and correlated. Furthermore, the membrane salt permeability coefficient K s from the manufacturer system analysis program (ROSA) is given and discussed. The transport governing equations are programmed in a way that facilitates the achievement of a realistic parametric study. The results showed that the permeate flux increases significantly as the feed pressure increases. Also, it increases significantly as the feed salt concentration decreases, and also as the feed temperature and pressure increase. Meanwhile, the permeator salt rejection increases significantly as the feed pressure increases, and decreases significantly as the feed temperature increases. The study of the leading element of the array showed that there are constraints that must be considered, such as maximum membrane flux, maximum applied feed pressure, maximum feed flow rate and maximum feed temperature. Therefore, to attain the maximum membrane flux, the applied feed pressure must be lowered when the feed temperature is increased. In the case where the feed temperature is increased from 18 deg.. C to 45 deg.. C, a pressure saving of between 7% and 26% is achieved, according to the feed salt concentration and feed flow rate. (author)

  8. Human versus Computer Controlled Selection of Ventilator Settings: An Evaluation of Adaptive Support Ventilation and Mid-Frequency Ventilation

    Directory of Open Access Journals (Sweden)

    Eduardo Mireles-Cabodevila

    2012-01-01

    Full Text Available Background. There are modes of mechanical ventilation that can select ventilator settings with computer controlled algorithms (targeting schemes. Two examples are adaptive support ventilation (ASV and mid-frequency ventilation (MFV. We studied how different clinician-chosen ventilator settings are from these computer algorithms under different scenarios. Methods. A survey of critical care clinicians provided reference ventilator settings for a 70 kg paralyzed patient in five clinical/physiological scenarios. The survey-derived values for minute ventilation and minute alveolar ventilation were used as goals for ASV and MFV, respectively. A lung simulator programmed with each scenario’s respiratory system characteristics was ventilated using the clinician, ASV, and MFV settings. Results. Tidal volumes ranged from 6.1 to 8.3 mL/kg for the clinician, 6.7 to 11.9 mL/kg for ASV, and 3.5 to 9.9 mL/kg for MFV. Inspiratory pressures were lower for ASV and MFV. Clinician-selected tidal volumes were similar to the ASV settings for all scenarios except for asthma, in which the tidal volumes were larger for ASV and MFV. MFV delivered the same alveolar minute ventilation with higher end expiratory and lower end inspiratory volumes. Conclusions. There are differences and similarities among initial ventilator settings selected by humans and computers for various clinical scenarios. The ventilation outcomes are the result of the lung physiological characteristics and their interaction with the targeting scheme.

  9. Ventilation of radioactive enclosures; Ventilation des enceintes radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Caminade, F; Laurent, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Mechanical, physical and chemical manipulations on radioactive products must be carried out in properly ventilated enclosed places. The air extracted can only be discharged into the atmosphere after a correct filtration. The power of the ventilation systems is a function of the dimensions and purpose of the enclosure? The choice of types of filter is determined by the physical state and chemical nature of the radioactive materials to be manipulated. This study deals with the individual equipment of small installations: glove boxes, manipulation boxes with outside control and, if necessary, production chambers (maximum useful volume: 5 m{sup 3}). The performances of three types of 'ventilators', and the modifications provided by the addition of filters, are measured and compared. (author) [French] Les manipulations oceaniques, physiques et chimiques sur des produits radioactifs doivent s'effectuer dans des enceintes convenablement ventilees. L'air extrait ne peut etre rejete dans l'atmosphere qu'apres une filtration correcte. La puissance des installations de ventilation est fonction des dimensions de l'enceinte et de son utilisation. Le choix des types de filtres est determine par l'etat physique et la nature ehimique des corps radioactifs manipules. Notre etude porte sur l'equipement individuel d'installations de petites dimensions: boites a gants, boites a pinces et, a la rigueur, enceintes de production (volume maximum utilisable 5 m{sup 3}). Nous mesurons et comparons les performances de trois types de 'ventilateurs' et les modifications apportees par l'adjonction de filtres. (auteur)

  10. Ventilation effectiveness : health benefits of heat recovery ventilators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-08-15

    Studies have shown that the installation of a heat recovery ventilator (HRV) in homes in northern Canada could improve indoor air quality and the respiratory health of inhabitants. Low ventilation rates are common in many homes in the North because the climate is severe, homes are smaller and lack basements, and occupancies are higher, leading to unhealthy indoor air quality. Northern communities also have a high rate of respiratory infections. HRVs recover much of the energy used to ventilate, which is desirable in cold regions with high heating costs. For the study, the test sample was divided into two types of houses, notably houses with active HRVs and those with control HRVs that were installed and operated but that did not function. The study results showed that HRVs provided increased ventilation. Complaints by residents about HRV noise, discomfort, or low humidity were common but equally spread between those with active and placebo HRVs. The study showed that the system design needs to be improved to better suit the needs of Inuit families. The nature of northern housing presents installation and maintenance challenges. It is hard to retrofit HRV ducting inside small, existing houses, and building supplies arrive infrequently, so detailed planning and careful take-offs of all supplies and materials must be done well in advance of construction. In addition, contractors are hard to locate and have variable expertise, and there is little technical follow-up. Robust technical support by local contractors and housing authorities is therefore important. 2 refs.

  11. Solar collector design with respect to moisture problems

    DEFF Research Database (Denmark)

    Holck, Ole; Svendsen, Svend; Brunold, Stefan

    2003-01-01

    more ventilation openings should be made and what influence the insulation material has. Guidelines for collector designers are proposed. The design guidelines provide some suggestions to be considered during the design of solar collectors.The work was carried out within the framework of the working...... group Materials in Solar Thermal Collectors of the International Energy Agency-Solar Heating and Cooling Programme....... the design of the collector, the location and size of ventilation holes, properties of the insulation materials and dimension of the solar collector box are parameters that have to be taken into account for the optimisation in order to achieve the most favourable microclimate to prevent corrosion...

  12. Decisional responsibility for mechanical ventilation and weaning

    DEFF Research Database (Denmark)

    Rose, Louise; Blackwood, Bronagh; Egerod, Ingrid

    2011-01-01

    Optimal management of mechanical ventilation and weaning requires dynamic and collaborative decision making to minimize complications and avoid delays in the transition to extubation. In the absence of collaboration, ventilation decision making may be fragmented, inconsistent, and delayed. Our...

  13. Perioperative lung protective ventilation in obese patients

    NARCIS (Netherlands)

    Fernandez-Bustamante, Ana; Hashimoto, Soshi; Serpa Neto, Ary; Moine, Pierre; Vidal Melo, Marcos F.; Repine, John E.

    2015-01-01

    The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent

  14. The School Advanced Ventilation Engineering Software (SAVES)

    Science.gov (United States)

    The School Advanced Ventilation Engineering Software (SAVES) package is a tool to help school designers assess the potential financial payback and indoor humidity control benefits of Energy Recovery Ventilation (ERV) systems for school applications.

  15. Improvements of uranium mine ventilation system

    International Nuclear Information System (INIS)

    Liu Changrong; Zhou Xinghuo; Liu Zehua; Wang Zhiyong

    2007-01-01

    Ventilation has been proved to be a main method to eliminate radon and its daughters in uranium mines. According to the practical rectifications of uranium mine ventilation system, the improved measures are summarized. (authors)

  16. Annex to Solar heat storages in district heating networks. Comprehensive list of Danish literature and R and D projects

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This annex relates to the report 'Solar heat storages in district heating networks', which has been elaborated to inform about the Danish experiences and findings on the use of central solar heating plants in district heating networks, especially with the focus on the development of the storage part of the systems. The report has been funded as part of the IEE PREHEAT cooperation and by Energinet.dk, project no. 2006-2-6750. (au)

  17. Ventilation area measured with eit in order to optimize peep settings in mechanically ventilated patients

    NARCIS (Netherlands)

    Blankman, P; Groot Jebbink, E; Preis, C; Bikker, I.; Gommers, D.

    2012-01-01

    INTRODUCTION. Electrical Impedance Tomography (EIT) is a non-invasive imaging technique, which can be used to visualize ventilation. Ventilation will be measured by impedance changes due to ventilation. OBJECTIVES. The aim of this study was to optimize PEEP settings based on the ventilation area of

  18. Initial ventilator settings for critically ill patients

    OpenAIRE

    Kilickaya, Oguz; Gajic, Ognjen

    2013-01-01

    The lung-protective mechanical ventilation strategy has been standard practice for management of acute respiratory distress syndrome (ARDS) for more than a decade. Observational data, small randomized studies and two recent systematic reviews suggest that lung protective ventilation is both safe and potentially beneficial in patients who do not have ARDS at the onset of mechanical ventilation. Principles of lung-protective ventilation include: a) prevention of volutrauma (tidal volume 4 to 8 ...

  19. Building ventilation, state of the art, prospective

    International Nuclear Information System (INIS)

    1995-10-01

    This conference is composed of 21 communications and 21 posters in the domain of building ventilation and indoor air quality; the main themes are: indoor air quality assessment and optimization; performance enhancement and optimization of ventilation systems and equipment; ventilation systems for renovated and rehabilitated buildings; French and European regulations, standardizations and certifications; experimental and numerical simulation studies concerning ventilation systems, air flow, temperature distribution, air quality, radon decontamination, thermal comfort and acoustic levels in buildings

  20. Artificial humidification for the mechanically ventilated patient

    OpenAIRE

    Selvaraj, Nelson

    2010-01-01

    Caring for patients who are mechanically ventilated poses many\\ud challenges for critical care nurses. It is important to humidify the\\ud patient’s airways artificially to prevent complications such as\\ud ventilator-associated pneumonia. There is no gold standard to\\ud determine which type of humidification is best for patients who\\ud are artificially ventilated. This article provides an overview of\\ud commonly used artificial humidification for mechanically ventilated\\ud patients and discuss...

  1. Artificial humidification for the mechanically ventilated patient.

    Science.gov (United States)

    Selvaraj, N

    Caring for patients who are mechanically ventilated poses many challenges for critical care nurses. It is important to humidify the patient's airways artificially to prevent complications such as ventilator-associated pneumonia. There is no gold standard to determine which type of humidification is best for patients who are artificially ventilated. This article provides an overview of commonly used artificial humidification for mechanically ventilated patients and discusses nurses' responsibilities in caring for patients receiving artificial humidification.

  2. High-Frequency Percussive Ventilation Revisited

    Science.gov (United States)

    2010-01-01

    be implemented. ‡ Follow the reverse of the ventilation sequence if respiratory alkalosis develops—however, start at ventilation goal sequence 1 not at...High-frequency percussive ventilation (HFPV) has demonstrated a potential role as a rescue option for refractory acute respiratory distress syndrome...frequency percussive ventilation (HFPV) has demon- strated a potential role as a salvage option for refrac- tory acute respiratory distress syndrome

  3. Performance comparison of 15 transport ventilators.

    Science.gov (United States)

    Chipman, Daniel W; Caramez, Maria P; Miyoshi, Eriko; Kratohvil, Joseph P; Kacmarek, Robert M

    2007-06-01

    Numerous mechanical ventilators are designed and marketed for use in patient transport. The complexity of these ventilators differs considerably, but very few data exist to compare their operational capabilities. Using bench and animal models, we studied 15 currently available transport ventilators with regard to their physical characteristics, gas consumption (duration of an E-size oxygen cylinder), battery life, ease of use, need for compressed gas, ability to deliver set ventilation parameters to a test lung under 3 test conditions, and ability to maintain ventilation and oxygenation in normal and lung-injured sheep. Most of the ventilators tested were relatively simple to operate and had clearly marked controls. Oxygen cylinder duration ranged from 30 min to 77 min. Battery life ranged from 70 min to 8 hours. All except 3 of the ventilators were capable of providing various F(IO2) values. Ten of the ventilators had high-pressure and patient-disconnect alarms. Only 6 of the ventilators were able to deliver all settings as specifically set on the ventilator during the bench evaluation. Only 4 of the ventilators were capable of maintaining ventilation, oxygenation, and hemodynamics in both the normal and the lung-injured sheep. Only 2 of the ventilators met all the trial targets in all the bench and animal tests. With many of the ventilators, certain of the set ventilation parameters were inaccurate (differed by > 10% from the values from a cardiopulmonary monitor). The physical characteristics and high gas consumption of some of these ventilators may render them less desirable for patient transport.

  4. Implementation of natural ventilation in pig houses

    NARCIS (Netherlands)

    Klooster, van 't C.E.

    1994-01-01

    A description of experimental work and discussion on implementation of natural ventilation in pig houses is given. A literature review describes the state of the art, animal growth data are given. It includes characterization of ventilation openings, a technique to estimate the ventilation

  5. 46 CFR 98.25-75 - Ventilation.

    Science.gov (United States)

    2010-10-01

    ... shall be fitted with efficient natural or mechanical ventilation. (b) Enclosed compartments in which... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation. 98.25-75 Section 98.25-75 Shipping COAST... Ventilation. (a) All enclosed spaces containing cargo tanks fitted with bottom outlet connections shall be...

  6. 46 CFR 194.10-25 - Ventilation.

    Science.gov (United States)

    2010-10-01

    ... magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design... vans shall be provided with natural ventilation sufficient to maintain the inside air temperature below... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation. 194.10-25 Section 194.10-25 Shipping COAST...

  7. 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...

  8. 14 CFR 252.9 - Ventilation systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9... REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully functioning. Fully functioning for this purpose means operating so...

  9. Ventilation strategies and indoor environment in classrooms

    DEFF Research Database (Denmark)

    Zhang, Chen; Liu, Li

    2017-01-01

    Compared with the other building types, the school building has much higher occupancy density and ventilation demand. In Demark, most of the school buildings are ventilated by natural manner. There is a risk of poor indoor environment associated with the lack of ventilation system or insufficient...

  10. Intelligent ventilation in the intensive care unit

    Directory of Open Access Journals (Sweden)

    Sigal Sviri

    2012-08-01

    Full Text Available Objectives. Automated, microprocessor-controlled, closed-loop mechanical ventilation has been used in our Medical Intensive Care Unit (MICU at the Hadassah Hebrew-University Medical Center for the past 15 years; for 10 years it has been the primary (preferred ventilator modality. Design and setting. We describe our clinical experience with adaptive support ventilation (ASV over a 6-year period, during which time ASV-enabled ventilators became more readily available and were used as the primary (preferred ventilators for all patients admitted to the MICU. Results. During the study period, 1 220 patients were ventilated in the MICU. Most patients (84% were ventilated with ASV on admission. The median duration of ventilation with ASV was 6 days. The weaning success rate was 81%, and tracheostomy was required in 13%. Sixty-eight patients (6% with severe hypoxia and high inspiratory pressures were placed on pressure-controlled ventilation, in most cases to satisfy a technical requirement for precise and conservative administration of inhaled nitric oxide. The overall pneumothorax rate was less than 3%, and less than 1% of patients who were ventilated only using ASV developed pneumothorax. Conclusions. ASV is a safe and acceptable mode of ventilation for complicated medical patients, with a lower than usual ventilation complication rate.

  11. 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

  12. 21 CFR 868.5895 - Continuous ventilator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continuous ventilator. 868.5895 Section 868.5895...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5895 Continuous ventilator. (a) Identification. A continuous ventilator (respirator) is a device intended to mechanically control or assist...

  13. Computational Fluid Dynamics in Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Allard, Francis; Awbi, Hazim B.

    2008-01-01

    Computational Fluid Dynamics in Ventilation Design is a new title in the is a new title in the REHVA guidebook series. The guidebook is written for people who need to use and discuss results based on CFD predictions, and it gives insight into the subject for those who are not used to work with CFD...

  14. Ventilation system in fire modelization

    International Nuclear Information System (INIS)

    Cordero Garcia, S.

    2012-01-01

    There is a model of fire in an enclosure formed by two rooms. In one of them, it will cause the fire and check how the system of ventilation in different configurations responds. In addition, the behavior of selected targets, which will be a configuration of cables similar to those found in nuclear power stations will be analyzed.

  15. Cardiogenic oscillation induced ventilator autotriggering

    Directory of Open Access Journals (Sweden)

    Narender Kaloria

    2015-01-01

    Full Text Available Cardiogenic oscillation during mechanical ventilation can auto-trigger the ventilator resembling patient initiated breadth. This gives a false sense of intact respiratory drive and determination brain death, even if other tests are positive, is not appropriate in such a situation. It will prolong the ICU stay and confound the brain-death determination. In this case report, we describe a 35 year old man who was brought to the hospital after many hours of critical delay following multiple gun shot injuries. The patient suffered a cardiac arrest while on the way from another hospital. After an emergency laparotomy, patient was shifted to Intensive Care Unit (ICU with Glasgow Coma Scale (GCS score of E1VTM1 and was mechanically ventilated. Despite absence of brainstem reflexes, the ventilator continued to be triggered on continuous positive airway pressure (CPAP mode and the patient maintained normal oxygen saturation and acceptable levels of carbon dioxide. An apnoea test confirmed absent respiratory drive. Ventilatory waveform graph analysis, revealed cardiogenic oscillation as the cause for autotrigerring.

  16. Design ventilátoru

    OpenAIRE

    Macháčková, Petra

    2013-01-01

    Předmětem této bakalářské práce je návrh designu stolního ventilátoru. Hlavní myšlenkou je inovativní přístup a dodržení technických, estetických a ergonomických požadavků a současně splnění psychologických a ekonomických funkcí. Navržený ventilátor by měl využívat inovativní technologie bezlopatkových ventilátorů. Ventilátor by měl působit jako vhodný doplněk do moderního interiéru. Cílem je propojit originální design s modernizací přístroje při splnění obecných předpokladů průmyslového desi...

  17. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects....

  18. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    Ventilation systems with vertical displacement flow have been used in industrial areas with extensive heat loads for many years. Hot and contaminant air is carried directly from the occupied zone towards the ceiling by hot processes and other activities which create a natural convection flow....

  19. ENERGY STAR Certified Ventilating Fans

    Science.gov (United States)

    Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Ventilating Fans that are effective as of October 1, 2015. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/index.cfm?c=vent_fans.pr_crit_vent_fans

  20. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    ... to stop eating (fast), be on a special diet, or take any medicines before the test. A chest x-ray is usually done before or after a ventilation and perfusion scan. You wear a hospital gown or comfortable clothing that does not have ...

  1. Comparison of Different Technologies for Integrated Solar Combined Cycles: Analysis of Concentrating Technology and Solar Integration

    Directory of Open Access Journals (Sweden)

    Antonio Rovira

    2018-04-01

    Full Text Available This paper compares the annual performance of Integrated Solar Combined Cycles (ISCCs using different solar concentration technologies: parabolic trough collectors (PTC, linear Fresnel reflectors (LFR and central tower receiver (CT. Each solar technology (i.e. PTC, LFR and CT is proposed to integrate solar energy into the combined cycle in two different ways. The first one is based on the use of solar energy to evaporate water of the steam cycle by means of direct steam generation (DSG, increasing the steam production of the high pressure level of the steam generator. The other one is based on the use of solar energy to preheat the pressurized air at the exit of the gas turbine compressor before it is introduced in the combustion chamber, reducing the fuel consumption. Results show that ISCC with DSG increases the yearly production while solar air heating reduces it due to the incremental pressure drop. However, air heating allows significantly higher solar-to-electricity efficiencies and lower heat rates. Regarding the solar technologies, PTC provides the best thermal results.

  2. Volume-Targeted Ventilation in the Neonate: Benchmarking Ventilators on an Active Lung Model.

    Science.gov (United States)

    Krieger, Tobias J; Wald, Martin

    2017-03-01

    Mechanically ventilated neonates have been observed to receive substantially different ventilation after switching ventilator models, despite identical ventilator settings. This study aims at establishing the range of output variability among 10 neonatal ventilators under various breathing conditions. Relative benchmarking test of 10 neonatal ventilators on an active neonatal lung model. Neonatal ICU. Ten current neonatal ventilators. Ventilators were set identically to flow-triggered, synchronized, volume-targeted, pressure-controlled, continuous mandatory ventilation and connected to a neonatal lung model. The latter was configured to simulate three patients (500, 1,500, and 3,500 g) in three breathing modes each (passive breathing, constant active breathing, and variable active breathing). Averaged across all weight conditions, the included ventilators delivered between 86% and 110% of the target tidal volume in the passive mode, between 88% and 126% during constant active breathing, and between 86% and 120% under variable active breathing. The largest relative deviation occurred during the 500 g constant active condition, where the highest output machine produced 147% of the tidal volume of the lowest output machine. All machines deviate significantly in volume output and ventilation regulation. These differences depend on ventilation type, respiratory force, and patient behavior, preventing the creation of a simple conversion table between ventilator models. Universal neonatal tidal volume targets for mechanical ventilation cannot be transferred from one ventilator to another without considering necessary adjustments.

  3. Effect of Pre-heating on Microtensile Bond Strength of Composite Resin to Dentin.

    Directory of Open Access Journals (Sweden)

    Abdolrahim Davari

    2014-10-01

    Full Text Available Direct composite resin restorations are widely used and the impact of different storage temperatures on composites is not well understood. The purpose of this study was to evaluate the microtensile bond strength of composite to dentin after different pre-curing temperatures.Occlusal surfaces of 44 human molars were ground with diamond burs under water coolant and polished with 600 grit silicon carbide papers to obtain flat dentin surfaces. The dentin was etched with 37% phosphoric acid and bonded with Adper Single Bond 2 according to the manufacturer's instructions. The specimens were randomly divided into two groups (n=22 according to the composite resin applied: FiltekP60 and Filtek Z250. Each group included three subgroups of composite resin pre-curing temperatures (4°C, 23°C and 37°C. Composite resins were applied to the dentin surfaces in a plastic mold (8mm in diameter and 4mm in length incrementally and cured. Twenty-two composite-to-dentin hour-glass sticks with one mm(2 cross-sectional area per group were prepared. Microtensile bond strength measurements were made using a universal testing machine at a crosshead speed of one mm/min. For statistical analysis, t-test, one-way and two-way ANOVA were used. The level of significance was set at P<0.05.Filtek P60 pre-heated at 37ºC had significantly higher microtensile bond strength than Filtek Z250 under the same condition. The microtensile bond strengths were not significantly different at 4ºC, 23ºC and 37ºC subgroups of each composite resin group.Filtek P60 and Filtek Z250 did not have significantly different microtensile bond strengths at 4ºC and 23ºC but Filtek P60 had significantly higher microtensile bond strength at 37 ºC. Composite and temperature interactions had significant effects on the bond strength.

  4. Establishment of welding process without PWHT and preheating in SGV480 plate for nuclear reactor containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Nozomu; Higashikubo, Tomohiro; Nagamura, Takafumi [Mitsubishi Heavy Industries. Ltd., Kobe Shipyard and Machinery Works (Japan); Yoshimoto Kentaro [Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan). Takasago Research and Development Center

    2000-07-01

    Ordinances of Japan's Ministry of International Trade and Industry provide that welded joints more than 38 mm thick used in nuclear reactor containment vessels undergo Post Weld Heat Treatment (PWHT). PWHT is difficult to apply in the field, however. We made SGV480 plate tougher and more weldable by using a Thermo-Mechanical Control Process (TMCP) in rolling. Such plate can be used without PWHT or preheating up to 55 mm thick at lowest service temperature -19degC. (author)

  5. MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

    OpenAIRE

    Fat'yanov, Oleg V.; Asimow, P. D.

    2014-01-01

    Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority ...

  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. Significant Improvements in Pyranometer Nighttime Offsets Using High-Flow DC Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Kutchenreiter, Mark; Michalski, J.J.; Long, C.N.; Habte, Aron

    2017-05-22

    Accurate solar radiation measurements using pyranometers are required to understand radiative impacts on the Earth's energy budget, solar energy production, and to validate radiative transfer models. Ventilators of pyranometers, which are used to keep the domes clean and dry, also affect instrument thermal offset accuracy. This poster presents a high-level overview of the ventilators for single-black-detector pyranometers and black-and-white pyranometers. For single-black-detector pyranometers with ventilators, high-flow-rate (50-CFM and higher), 12-V DC fans lower the offsets, lower the scatter, and improve the predictability of nighttime offsets compared to lower-flow-rate (35-CFM), 120-V AC fans operated in the same type of environmental setup. Black-and-white pyranometers, which are used to measure diffuse horizontal irradiance, sometimes show minor improvement with DC fan ventilation, but their offsets are always small, usually no more than 1 W/m2, whether AC- or DC-ventilated.

  8. Minute Ventilation Limitations of Two Field Transport Ventilators.

    Science.gov (United States)

    Szpisjak, Dale F; Horn, Gregory; Shalov, Samuel; Abes, Alvin Angelo; Van Decar, Lauren

    2017-01-01

    Knowledge of transport ventilator performance impacts patient safety. This study compared minute ventilation (V E ) of the MOVES and Uni-Vent 731 when ventilating the VentAid Training Test Lung with compliance (C) ranging from 0.02 to 0.10 L/cm H 2 O and three different airway resistances (R) (none, Rp5, or Rp20). Tidal volume (V T ) was 800 ± 25 mL. Respiratory rate was increased to ventilator's maximum or until auto-PEEP > 5 cm H 2 O. Respiratory parameters were recorded with the RSS 100HR Research Pneumotach. Data were reported as median (interquartile range). Peak inspiratory pressure (PIP) of the Uni-Vent and MOVES ranged from 22.3 (22.2-22.5) to 82.6 (82.2-83.2) and 20.8 (20.6-20.9) to 50.6 (50.2-50.9) cm H 2 O, respectively. V E of the Uni-Vent and MOVES ranged from 17.7 (17.7-17.7) to 31.5 (31.5-31.5) and 11.3 (10.5-11.3) to 20.2 (19.7-20.5) L/min, respectively. Linear regression demonstrated strong, negative correlation of V E with PIP for the MOVES (V E [L/min] = 26 - 0.31 × PIP [cm H 2 O], r = -0.97) but weak, positive correlation for the Uni-Vent (r = 0.05). Uni-Vent V E exceeded MOVES V E under each test condition (p = 0.0002). If patient V E requirements exceed those predicted by the MOVES regression equation, then using the Uni-Vent should be considered. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  9. Papers presented at ISES solar world congress 1993 in Budapest, Hungary

    International Nuclear Information System (INIS)

    1993-09-01

    Papers presented at the ISES Solar World Congress 1993 by researchers employed at the Thermal Insulation Laboratory at the Technical University of Denmark. The subjects dealt with are: the design of small domestic hot water low-flow solar heating systems, heat storage for large low-flow solar heating systems, the monitoring of Danish marketed solar heating systems, conversion of indoor measurements to outdoor long term performances for low flow solar collectors, optimum ventilation rate of solar collectors, the construction of seasonal heat storage based on a pit with clay membrane, a solar house with a new solar collector, and a framing system for solar wall glazings. (AB)

  10. 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

  11. Comparative studies on the performance and emissions of a direct injection diesel engine fueled with neem oil and pumpkin seed oil biodiesel with and without fuel preheater.

    Science.gov (United States)

    Ramakrishnan, Muneeswaran; Rathinam, Thansekhar Maruthu; Viswanathan, Karthickeyan

    2018-02-01

    In the present experimental analysis, two non-edible oils namely neem oil and pumpkin seed oil were considered. They are converted into respective biodiesels namely neem oil methyl ester (B1) and pumpkin seed oil methyl ester (B2) through transesterification process and their physical and chemical properties were examined using ASTM standards. Diesel was used as a baseline fuel in Kirloskar TV1 model direct injection four stroke diesel engine. A fuel preheater was designed and fabricated to operate at various temperatures (60, 70, and 80 °C). Diesel showed higher brake thermal efficiency (BTE) than biodiesel samples. Lower brake specific fuel consumption (BSFC) was obtained with diesel than B1 sample. B1 exhibited lower BSFC than B2 sample without preheating process. High preheating temperature (80 °C) results in lower fuel consumption for B1 sample. The engine emission characteristics like carbon monoxide (CO), hydrocarbon (HC), and smoke were found lower with B1 sample than diesel and B2 except oxides of nitrogen (NOx) emission. In preheating of fuel, B1 sample with high preheating temperature showed lower CO, HC, and smoke emission (except NOx) than B2 sample.

  12. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  13. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  14. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  16. Thermal and photovoltaic solar system in Urban hotel; Sistema solar termico y fotovoltaico en hotel urbano

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, J.; Perpinan, O.; Ramirez, F.; Eyras, R.; Vega, J.

    2004-07-01

    The article describes the Solar Energy installations that are being carried out in the Hotel Monte Malaga promoted by the Gabriel Rojas Group. We can consider this project to be pioneer in Spain since it uses Photovoltaic Solar Panels as parasols in facades in order to reduce its frozen load and with the intention of producing electric energy that will be injected to the grid. In addition, solar collectors over roof are being used distributed in a totally integrated way with the building for the preheating of the sanitary hot water producing a saving of around 90% of the natural gas consume. This entire project is carried out in an ultramodern design using different bioclimatic techniques that turns this building into a singular one. (Author)

  17. Aerodynamics of Ventilation in Termite Mounds

    Science.gov (United States)

    Bailoor, Shantanu; Yaghoobian, Neda; Turner, Scott; Mittal, Rajat

    2017-11-01

    Fungus-cultivating termites collectively build massive, complex mounds which are much larger than the size of an individual termite and effectively use natural wind and solar energy, as well as the energy generated by the colony's own metabolic activity to maintain the necessary environmental condition for the colony's survival. We seek to understand the aerodynamics of ventilation and thermoregulation of termite mounds through computational modeling. A simplified model accounting for key mound features, such as soil porosity and internal conduit network, is subjected to external draft conditions. The role of surface flow conditions in the generation of internal flow patterns and the ability of the mound to transport gases and heat from the nursery are examined. The understanding gained from our study could be used to guide sustainable bio-inspired passive HVAC system design, which could help optimize energy utilization in commercial and residential buildings. This research is supported by a seed Grant from the Environment, Energy Sustainability and Health Institute of the Johns Hopkins University.

  18. Stockpiling Ventilators for Influenza Pandemics.

    Science.gov (United States)

    Huang, Hsin-Chan; Araz, Ozgur M; Morton, David P; Johnson, Gregory P; Damien, Paul; Clements, Bruce; Meyers, Lauren Ancel

    2017-06-01

    In preparing for influenza pandemics, public health agencies stockpile critical medical resources. Determining appropriate quantities and locations for such resources can be challenging, given the considerable uncertainty in the timing and severity of future pandemics. We introduce a method for optimizing stockpiles of mechanical ventilators, which are critical for treating hospitalized influenza patients in respiratory failure. As a case study, we consider the US state of Texas during mild, moderate, and severe pandemics. Optimal allocations prioritize local over central storage, even though the latter can be deployed adaptively, on the basis of real-time needs. This prioritization stems from high geographic correlations and the slightly lower treatment success assumed for centrally stockpiled ventilators. We developed our model and analysis in collaboration with academic researchers and a state public health agency and incorporated it into a Web-based decision-support tool for pandemic preparedness and response.

  19. International Ventilation Cooling Application Database

    DEFF Research Database (Denmark)

    Holzer, Peter; Psomas, Theofanis Ch.; OSullivan, Paul

    2016-01-01

    The currently running International Energy Agency, Energy and Conservation in Buildings, Annex 62 Ventilative Cooling (VC) project, is coordinating research towards extended use of VC. Within this Annex 62 the joint research activity of International VC Application Database has been carried out...... and locations, using VC as a mean of indoor comfort improvement. The building-spreadsheet highlights distributions of technologies and strategies, such as the following. (Numbers in % refer to the sample of the database’s 91 buildings.) It may be concluded that Ventilative Cooling is applied in temporary......, systematically investigating the distribution of technologies and strategies within VC. The database is structured as both a ticking-list-like building-spreadsheet and a collection of building-datasheets. The content of both closely follows Annex 62 State-Of-The- Art-Report. The database has been filled, based...

  20. Displacement Ventilation in Hospital Environments

    DEFF Research Database (Denmark)

    Li, Yuguo; Nielsen, Peter V.; Sandberg, Mats

    2011-01-01

    Hospital differ from conventional buildings in terms of ventilation needs. Exhaled infectious droplets or droplet nuclei of an infected patient need to be removed in general wards, waiting areas and isolation rooms to minimize transmission to health-care workers, other patients and visitors. In m....... In most health-care environments, harmful microorganisms and infectious aerosols may exist in relatively high concentration. They are particularly harmful to patients due to reduced immunity, and to those with open wounds.......Hospital differ from conventional buildings in terms of ventilation needs. Exhaled infectious droplets or droplet nuclei of an infected patient need to be removed in general wards, waiting areas and isolation rooms to minimize transmission to health-care workers, other patients and visitors...

  1. Initial mechanical ventilator settings and lung protective ventilation in the ED.

    Science.gov (United States)

    Wilcox, Susan R; Richards, Jeremy B; Fisher, Daniel F; Sankoff, Jeffrey; Seigel, Todd A

    2016-08-01

    Mechanical ventilation with low tidal volumes has been shown to improve outcomes for patients both with and without acute respiratory distress syndrome. This study aims to characterize mechanically ventilated patients in the emergency department (ED), describe the initial ED ventilator settings, and assess for associations between lung protective ventilation strategies in the ED and outcomes. This was a multicenter, prospective, observational study of mechanical ventilation at 3 academic EDs. We defined lung protective ventilation as a tidal volume of less than or equal to 8 mL/kg of predicted body weight and compared outcomes for patients ventilated with lung protective vs non-lung protective ventilation, including inhospital mortality, ventilator days, intensive care unit length of stay, and hospital length of stay. Data from 433 patients were analyzed. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Two hundred sixty-one patients (60.3%) received lung protective ventilation, but most patients were ventilated with a low positive end-expiratory pressure, high fraction of inspired oxygen strategy. Patients were ventilated in the ED for a mean of 5 hours and 7 minutes but had few ventilator adjustments. Outcomes were not significantly different between patients receiving lung protective vs non-lung protective ventilation. Nearly 40% of ED patients were ventilated with non-lung protective ventilation as well as with low positive end-expiratory pressure and high fraction of inspired oxygen. Despite a mean ED ventilation time of more than 5 hours, few patients had adjustments made to their ventilators. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Ventilation-air conditioning system

    International Nuclear Information System (INIS)

    Kubokoya, Takashi.

    1991-01-01

    Heretofore, in ventilation-air conditioning systems in a nuclear power plant, exhaust gases from each of the ventilation-air conditioning systems of a reactor building, a turbine building, a waste processing building are joined and they are released into atmosphere from the top of a high main exhaustion stack. In order to build such a high main exhaustion stack, a considerable construction cost is required and, in addition, there is a worry of lacking balance with surrounding scenery. Then, in the present invention, exhaust gases are heated by waste heat in a turbine during their introduction from the ventilation-air conditioning facility in the building of a power plant to the main exhaust stack. With such a constitution, since the exhaust gases are heated and their temperature is elevated, they uprise by natural convection when they are released from the top of the main exhaustion stack to the atmosphere. Accordingly, they are released to a level higher than the conventional case in view of the volume of the blower which sends the exhaust gases under pressure, to diffuse them to the atmosphere more sufficiently compared with a conventional case. Further, the height of the main exhaustion stack can be reduced, enabling to minimize the cost for moving the blower. (T.M.)

  3. Effect of preheating on the damage to tungsten targets after repetitive ITER ELM-like heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Makhlay, V A [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Bandura, A N [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Byrka, O V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Garkusha, I E [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Chebotarev, V V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Tereshin, V I [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Landman, I [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany)

    2007-03-15

    The behaviour of a preheated tungsten target under repetitive pulsed plasma impacts of the energy density 0.75 MJ m{sup -2} with the pulse duration of 0.25 ms was studied with the quasi-stationary plasma accelerator (QSPA) Kh-50. Two identical samples of pure sintered tungsten have been exposed to numbers of pulses exceeding 100. One sample was maintained at room temperature and the other sample preheated at 650 deg. C. The experiments demonstrated that on the cold surface some macro-cracks dominate, but on the hot surface they do not develop. However, in both cases some fine meshes of micro-cracks are observed. With increasing the number of exposures, the width of the micro-cracks gradually increases, achieving 0.8-1.5 {mu}m after 100 pulses. In addition, the SEM shows some cellular structure with the cell sizes about 0.3 {mu}m, and after large numbers of exposures some blisters of sizes up to 100-150 {mu}m appear.

  4. MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

    Science.gov (United States)

    Fat'yanov, O. V.; Asimow, P. D.

    2014-05-01

    Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority of our experiments showed smooth monotonic increases in MgO sound speed and shock temperature with pressure from 197 to 243 GPa. The measured temperatures as well as the slopes of the pressure dependences for both temperature and sound speed were in good agreement with those calculated numerically for the solid phase at our peak shock compression conditions. Most observed sound speeds, however, were ~800 m/s higher than those predicted by the model. A single unconfirmed data point at 239 GPa showed anomalously low temperature and sound speed, which could both be explained by partial melting in this experiment and could suggest that the Hugoniot of MgO preheated to 2300 K crosses its melting line just slightly above 240 GPa.

  5. MgO melting curve constraints from shock temperature and rarefaction overtake measurements in samples preheated to 2300 K

    International Nuclear Information System (INIS)

    Fat'yanov, O V; Asimow, P D

    2014-01-01

    Continuing our effort to obtain experimental constraints on the melting curve of MgO at 100-200 GPa, we extended our target preheating capability to 2300 K. Our new Mo capsule design holds a long MgO crystal in a controlled thermal gradient until impact by a Ta flyer launched at up to 7.5 km/s on the Caltech two-stage light-gas gun. Radiative shock temperatures and rarefaction overtake times were measured simultaneously by a 6-channel VIS/NIR pyrometer with 3 ns time resolution. The majority of our experiments showed smooth monotonic increases in MgO sound speed and shock temperature with pressure from 197 to 243 GPa. The measured temperatures as well as the slopes of the pressure dependences for both temperature and sound speed were in good agreement with those calculated numerically for the solid phase at our peak shock compression conditions. Most observed sound speeds, however, were ∼800 m/s higher than those predicted by the model. A single unconfirmed data point at 239 GPa showed anomalously low temperature and sound speed, which could both be explained by partial melting in this experiment and could suggest that the Hugoniot of MgO preheated to 2300 K crosses its melting line just slightly above 240 GPa.

  6. Preliminary studies of using preheated carrier gas for on-line membrane extraction of semivolatile organic compounds.

    Science.gov (United States)

    Liu, Xinyu; Pawliszyn, Janusz

    2007-04-01

    In this paper, we present results for the on-line determination of semivolatile organic compounds (SVOCs) in air using membrane extraction with a sorbent interface-ion mobility spectrometry (MESI-IMS) system with a preheated carrier (stripping) gas. The mechanism of the mass transfer of SVOCs across a membrane was initially studied. In comparison with the extraction of volatile analytes, the mass transfer resistance that originated from the slow desorption from the internal membrane surface during the SVOC extraction processes should be taken into account. A preheated carrier gas system was therefore built to facilitate desorption of analytes from the internal membrane surface. With the benefit of a temperature gradient existing between the internal and external membrane surfaces, an increase in the desorption rate of a specific analyte at the internal surface and the diffusion coefficient within the membrane could be achieved while avoiding a decrease of the distribution constant on the external membrane interface. This technique improved both the extraction rate and response times of the MESI-IMS system for the analysis of SVOCs. Finally, the MESI-IMS system was shown to be capable of on-site measurement by monitoring selected polynuclear aromatic hydrocarbons emitted from cigarette smoke.

  7. Hydrodynamic and thermal mechanisms of filtration combustion inclinational instability based on non-uniform distribution of initial preheating temperature

    Science.gov (United States)

    Xia, Yongfang; Shi, Junrui; Xu, Youning; Ma, Rui

    2018-03-01

    Filtration combustion (FC) is one style of porous media combustion with inert matrix, in which the combustion wave front propagates, only downstream or reciprocally. In this paper, we investigate the FC flame front inclinational instability of lean methane/air mixtures flowing through a packed bed as a combustion wave front perturbation of the initial preheating temperature non-uniformity is assumed. The predicted results show that the growth rate of the flame front inclinational angle is proportional to the magnitude of the initial preheating temperature difference. Additionally, depending on gas inlet gas velocity and equivalence ratio, it is demonstrated that increase of gas inlet gas velocity accelerates the FC wave front deformation, and the inclinational instability evolves faster at lower equivalence ratio. The development of the flame front inclinational angle may be regarded as a two-staged evolution, which includes rapid increase, and approaching maximum value of inclinational angle due to the quasi-steady condition of the combustion system. The hydrodynamic and thermal mechanisms of the FC inclinational instability are analyzed. Consequently, the local propagation velocity of the FC wave front is non-uniform to result in the development of inclinational angle at the first stage of rapid increase.

  8. Measurement of Preheat and Shock Melting in Be Ablators During the First Few ns of the NIF Ignition Pulse

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D K; Prisbrey, S T; Page, R H; Braun, D G; Edwards, M J; Hibbard, R L; Moreno, K A; Mauldin, M P; Nikroo, A

    2008-05-28

    We have developed a scaled hohlraum platform to experimentally measure preheat in ablator materials during the first few nanoseconds of the radiation drive proposed for ignition experiments at the National Ignition Facility [J. A. Paisner, J. D. Boyes, S. A. Kumpan, et al., Laser Focus World 30, 75 (1994)]. The platform design approximates the radiation environment of the pole of the capsule by matching both the laser spot intensity and illuminated hohlraum wall fraction in scaled halfraums driven by the OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton, et al., Optics Communications 133, 495 (1997)]. A VISAR reflecting from the rear surface of the sample was used to measure sample motion prior to shock breakout. The experiments show that the first {approx}20 {micro}m of a Be ablator will be melted by radiation preheat, with subsequent material melted by the initial shock, in agreement with simulations. The experiments also show no evidence of anomalous heating of buried high-z doped layers in the ablator.

  9. A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

    Energy Technology Data Exchange (ETDEWEB)

    Huang Kejin [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: huangkj@mail.buct.edu.cn; Shan Lan; Zhu Qunxiong [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Qian Jixin [School of Information Science and Technology, Zhejiang University, Zhejiang 300027 (China)

    2008-06-15

    An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC.

  10. A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

    International Nuclear Information System (INIS)

    Huang Kejin; Shan Lan; Zhu Qunxiong; Qian Jixin

    2008-01-01

    An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC

  11. Development of a Residential Integrated Ventilation Controller

    Energy Technology Data Exchange (ETDEWEB)

    Staff Scientist; Walker, Iain; Sherman, Max; Dickerhoff, Darryl

    2011-12-01

    The goal of this study was to develop a Residential Integrated Ventilation Controller (RIVEC) to reduce the energy impact of required mechanical ventilation by 20percent, maintain or improve indoor air quality and provide demand response benefits. This represents potential energy savings of about 140 GWh of electricity and 83 million therms of natural gas as well as proportional peak savings in California. The RIVEC controller is intended to meet the 2008 Title 24 requirements for residential ventilation as well as taking into account the issues of outdoor conditions, other ventilation devices (including economizers), peak demand concerns and occupant preferences. The controller is designed to manage all the residential ventilation systems that are currently available. A key innovation in this controller is the ability to implement the concept of efficacy and intermittent ventilation which allows time shifting of ventilation. Using this approach ventilation can be shifted away from times of high cost or high outdoor pollution towards times when it is cheaper and more effective. Simulations, based on the ones used to develop the new residential ventilation requirements for the California Buildings Energy code, were used to further define the specific criteria and strategies needed for the controller. These simulations provide estimates of the energy, peak power and contaminant improvement possible for different California climates for the various ventilation systems. Results from a field test of the prototype controller corroborate the predicted performance.

  12. Temperature of gas delivered from ventilators.

    Science.gov (United States)

    Chikata, Yusuke; Onodera, Mutsuo; Imanaka, Hideaki; Nishimura, Masaji

    2013-01-01

    Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV). We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings. While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature. Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.

  13. Mechanical ventilators in US acute care hospitals.

    Science.gov (United States)

    Rubinson, Lewis; Vaughn, Frances; Nelson, Steve; Giordano, Sam; Kallstrom, Tom; Buckley, Tim; Burney, Tabinda; Hupert, Nathaniel; Mutter, Ryan; Handrigan, Michael; Yeskey, Kevin; Lurie, Nicole; Branson, Richard

    2010-10-01

    The supply and distribution of mechanical ventilation capacity is of profound importance for planning for severe public health emergencies. However, the capability of US health systems to provide mechanical ventilation for children and adults remains poorly quantified. The objective of this study was to determine the quantity of adult and pediatric mechanical ventilators at US acute care hospitals. A total of 5,752 US acute care hospitals included in the 2007 American Hospital Association database were surveyed. We measured the quantities of mechanical ventilators and their features. Responding to the survey were 4305 (74.8%) hospitals, which accounted for 83.8% of US intensive care unit beds. Of the 52,118 full-feature mechanical ventilators owned by respondent hospitals, 24,204 (46.4%) are pediatric/neonatal capable. Accounting for nonrespondents, we estimate that there are 62,188 full-feature mechanical ventilators owned by US acute care hospitals. The median number of full-feature mechanical ventilators per 100,000 population for individual states is 19.7 (interquartile ratio 17.2-23.1), ranging from 11.9 to 77.6. The median number of pediatric-capable device full-feature mechanical ventilators per 100,000 population younger than 14 years old is 52.3 (interquartile ratio 43.1-63.9) and the range across states is 22.1 to 206.2. In addition, respondent hospitals reported owning 82,755 ventilators other than full-feature mechanical ventilators; we estimate that there are 98,738 devices other than full-feature ventilators at all of the US acute care hospitals. The number of mechanical ventilators per US population exceeds those reported by other developed countries, but there is wide variation across states in the population-adjusted supply. There are considerably more pediatric-capable ventilators than there are for adults only on a population-adjusted basis.

  14. Numerical investigations of buoyancy-driven natural ventilation in a simple three-storey atrium building and thermal comfort evaluation

    International Nuclear Information System (INIS)

    Hussain, Shafqat; Oosthuizen, Patrick H.

    2013-01-01

    The numerical investigations of buoyancy-driven natural ventilation and thermal comfort evaluation in a simple three-storey atrium building as a part of the passive ventilation strategy was undertaken using a validated Computational Fluid Dynamic (CFD) model. The Reynolds Averaged Navier–Stokes (RANS) modeling approach with the SST-k–ω turbulence model and the discrete transfer radiation model (DTRM) was used for the numerical investigations. The steady-state governing equations were solved using a commercial solver FLUENT©. Various flow situations of the buoyancy-driven natural ventilation in the building during day and night time were examined. The numerical results obtained for the airflow rates, airflow patterns and temperature distributions inside the building are presented in this paper. Using the numerical results, the well-known thermal comfort indices PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for the evaluation of the thermal comfort conditions in the occupied regions of the building. It was noticed that thermal conditions prevailing in the occupied areas of the building as a result of using the buoyancy-driven ventilation were mostly in comfort zone. From the study of the night time ventilation, it was found that hot water (80 °C) circulation (heated by solar collectors during daytime) along the chimney walls during night time and heat sources present in the building can be useful in inducing night ventilation airflows in the building as a part of the passive ventilation strategy. -- Highlights: • A simple three-storey atrium building. • Numerical modeling of buoyancy-driven ventilation flow in the building. • Effect of solar intensity and geographical location on ventilation. • CFD predictions were used to calculate thermal comfort indices. • Evaluation of thermal comfort conditions for the occupants

  15. Particle deposition in ventilation ducts

    Energy Technology Data Exchange (ETDEWEB)

    Sippola, Mark Raymond [Univ. of California, Berkeley, CA (United States)

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 μm were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the

  16. City ventilation of Hong Kong at no-wind conditions

    Science.gov (United States)

    Yang, Lina; Li, Yuguo

    We hypothesize that city ventilation due to both thermally-driven mountain slope flows and building surface flows is important in removing ambient airborne pollutants in the high-rise dense city Hong Kong at no-wind conditions. Both spatial and temporal urban surface temperature profiles are an important boundary condition for studying city ventilation by thermal buoyancy. Field measurements were carried out to investigate the diurnal thermal behavior of urban surfaces (mountain slopes, and building exterior walls and roofs) in Hong Kong by using the infrared thermography. The maximum urban surface temperature was measured in the early noon hours (14:00-15:00 h) and the minimum temperature was observed just before sunrise (5:00 h). The vertical surface temperature of the building exterior wall was found to increase with height at daytime and the opposite occurred at nighttime. The solar radiation and the physical properties of the various urban surfaces were found to be important factors affecting the surface thermal behaviors. The temperature difference between the measured maximum and minimum surface temperatures of the four selected exterior walls can be at the highest of 16.7 °C in the early afternoon hours (15:00 h). Based on the measured surface temperatures, the ventilation rate due to thermal buoyancy-induced wall surface flows of buildings and mountain slope winds were estimated through an integral analysis of the natural convection flow over a flat surface. At no-wind conditions, the total air change rate by the building wall flows (2-4 ACH) was found to be 2-4 times greater than that by the slope flows due to mountain surface (1 ACH) due to larger building exterior surface areas and temperature differences with surrounding air. The results provide useful insights into the ventilation of a high-rise dense city at no-wind conditions.

  17. Experimental study on the operating characteristics of an inner preheating transpiring wall reactor for supercritical water oxidation: Temperature profiles and product properties

    International Nuclear Information System (INIS)

    Zhang, Fengming; Xu, Chunyan; Zhang, Yong; Chen, Shouyan; Chen, Guifang; Ma, Chunyuan

    2014-01-01

    A new process to generate multiple thermal fluids by supercritical water oxidation (SCWO) was proposed to enhance oil recovery. An inner preheating transpiring wall reactor for SCWO was designed and tested to avoid plugging in the preheating section. Hot water (400–600 °C) was used as auxiliary heat source to preheat the feed to the reaction temperature. The effect of different operating parameters on the performance of the inner preheating transpiring wall reactor was investigated, and the optimized operating parameters were determined based on temperature profiles and product properties. The reaction temperature is close to 900 °C at an auxiliary heat source flow of 2.79 kg/h, and the auxiliary heat source flow is determined at 6–14 kg/h to avoid the overheating of the reactor. The useful reaction time is used to quantitatively describe the feed degradation efficiency. The outlet concentration of total organic carbon (TOC out ) and CO in the effluent gradually decreases with increasing useful reaction time. The useful reaction time needed for complete oxidation of the feed is 10.5 s for the reactor. - Highlights: • A new process to generate multiple thermal fluids by SCWO was proposed. • An inner preheating transpiring wall reactor for SCWO was designed and tested. • Hot water was used as auxiliary heat source to preheat the feed at room temperature. • Effect of operating parameters on the performance of the reactor was investigated. • The useful reaction time required for complete oxidation of the feed is 10.5 s

  18. Receding Horizon Optimal Control of a Solar Greenhouse

    NARCIS (Netherlands)

    Ooteghem, van R.J.C.; Willigenburg, van L.G.; Straten, van G.

    2005-01-01

    A solar greenhouse has been designed that maximizes solar energy use and minimizes fossil energy consumption. It is based on a conventional Venlo greenhouse extended with a heat pump, a heat exchanger, an aquifer and ventilation with heat recovery. The goal is to minimize fossil energy consumption,

  19. Solar Shading System Based on Daylight Directing Glass Lamellas

    DEFF Research Database (Denmark)

    Laustsen, Jacob Birck; Santos, Inês; Svendsen, Svend

    2008-01-01

    The overheating problems in office buildings must be solved with efficient solar shadings in order to reduce the energy demand for cooling and ventilation. At the same time the solar shading should not reduce the daylight level in the building on overcast days because it would result in a lower...

  20. Solar Thermal AIR Collector Based on New Type Selective Coating

    Directory of Open Access Journals (Sweden)

    Musiy, R.Y.

    2014-01-01

    Full Text Available Based on the best for optical performance and selective coating solar thermal air collector, which operates by solar power on the principle of simultaneous ventilation and heating facilities, is designed. It can be used for vacation homes, museums, wooden churches, warehouses, garages, houses, greenhouses etc.

  1. Mathematical Modeling of Dual Intake Transparent Transpired Solar Collector

    Directory of Open Access Journals (Sweden)

    Thomas Semenou

    2015-01-01

    Full Text Available Nowadays, in several types of commercial or institutional buildings, a significant rise of transpired solar collectors used to preheat the fresh air of the building can be observed. Nevertheless, when the air mass flow rate is low, the collector efficiency collapses and a large amount of energy remains unused. This paper presents a simple yet effective mathematical model of a transparent transpired solar collector (TTC with dual intake in order to remove stagnation problems in the plenum and ensure a better thermal efficiency and more heat recovery. A thermal model and a pressure loss model were developed. Then, the combined model was validated with experimental data from the Solar Rating and Certification Corporation (SRCC. The results show that the collector efficiency can be up to 70% and even 80% regardless of operating conditions. The temperature gain is able to reach 20°K when the solar irradiation is high.

  2. Canadian solar export market study. Export policy recommendations

    Energy Technology Data Exchange (ETDEWEB)

    1983-11-01

    This report outlines policies and recommendations on the export of Canadian solar equipment and technology, with a view toward stimulating the domestic solar industry. The current picture is of an industry which is relatively small, operates in a competitive domestic market with low profit margins, and needs assistance in order to break into the world market. A number of recommendations are therefore made on the main thrust of industry and government solar export development activities. An export development program is described which includes a strategy of concentrating on a limited number of product lines, namely: low-temperature solar heating systems for recreational applications, integrated residential water heating systems, prepackaged commercial water heating systems, and industrial pre-heat systems. It is also recommended that this strategy be directed only at a limited number of target countries where the market justifies such activity. Market research, international cooperation agreements, promotional services, and proper export organization are also needed.

  3. Comparison of Heat Transfer Fluid and Direct Steam Generation technologies for Integrated Solar Combined Cycles

    International Nuclear Information System (INIS)

    Rovira, Antonio; Montes, María José; Varela, Fernando; Gil, Mónica

    2013-01-01

    At present time and in the medium term, Solar Thermal Power Plants are going to share scenario with conventional energy generation technologies, like fossil and nuclear. In such a context, Integrated Solar Combined Cycles (ISCCs) may be an interesting choice since integrated designs may lead to a very efficient use of the solar and fossil resources. In this work, different ISCC configurations including a solar field based on parabolic trough collectors and working with the so-called Heat Transfer Fluid (HTF) and Direct Steam Generation (DSG) technologies are compared. For each technology, four layouts have been studied: one in which solar heat is used to evaporate part of the high pressure steam of a bottoming Rankine cycle with two pressure levels, another that incorporates a preheating section to the previous layout, the third one that includes superheating instead of preheating and the last one including both preheating and superheating in addition to the evaporation. The analysis is made with the aim of finding out which of the different layouts reaches the best performance. For that purpose, three types of comparisons have been performed. The first one assesses the benefits of including a solar steam production fixed at 50 MW th . The second one compares the configurations with a standardised solar field size instead of a fixed solar steam production. Finally, the last one consists on an even more homogeneous comparison considering the same steam generator size for all the configurations as well as standardised solar fields. The configurations are studied by mean of exergy analyses. Several figures of merit are used to correctly assess the configurations. Results reveal that the only-evaporative DSG configuration becomes the best choice, since it benefits of both low irreversibility at the heat recovery steam generator and high thermal efficiency in the solar field. Highlights: ► ISCC configurations with DSG and HTF technologies are compared. ► Four

  4. The effects of opening areas on solar chimney performance

    Science.gov (United States)

    Ling, L. S.; Rahman, M. M.; Chu, C. M.; Misaran, M. S. bin; Tamiri, F. M.

    2017-07-01

    To enhance natural ventilation at day time, solar chimney is one of the suitable options for topical country like Malaysia. Solar chimney creates air flow due to stack effect caused by temperature difference between ambient and inside wall. In the solar chimney, solar energy is harvested by the inner wall that cause temperature rise compare to ambient. Therefore, the efficiency of the solar chimney depends on the availability of solar energy as well as the solar intensity. In addition, it is very hard to get good ventilation at night time by using a solar chimney. To overcome this problem one of the suitable valid option is to integrate solar chimney with turbine ventilator. A new type of solar chimney is designed and fluid flow analyzed with the computational fluid dynamics (CFD) software. The aim of CFD and theoretical study are to investigate the effect of opening areas on modified solar chimney performance. The inlet and outlet area of solar chimney are varied from 0.0224m2 to 0.6m2 and 0.1m2 to 0.14m2 respectively based on the changes of inclination angle and gap between inner and outer wall. In the CFD study the constant heat flux is considered as 500W/m2. CFD result shows that there is no significant relation between opening areas and the air flow rate through solar chimney but the ratio between inlet and outlet is significant on flow performance. If the area ratio between inlet and outlet are equal to two or larger, the performance of the solar chimney is better than the solar chimney with ratio lesser than two. The solar chimney performance does not effect if the area ratio between inlet and outlet varies from 1 to 2. This result will be useful for design and verification of actual solar chimney performance.

  5. Solar project description for Zien Mechanical Contractors-I single family residence, Milwaukee, Wisconsin

    Science.gov (United States)

    Beers, D.

    1980-02-01

    The Zien Mechanical site is a single family residence located in Milwaukee, Wisconsin. The home has two separate solar energy systems: an air system for space heating and cooling; a liquid system to preheat the potable hot water. The space heating and cooling system design and operation modes are described. The space heating system is designed to apply approximately 44 percent of the space heating requirements for the 1388 square foot residence. Engineering drawings are provided and the performance evaluation instrumentation is described.

  6. Comparative performances analysis of neonatal ventilators.

    Science.gov (United States)

    Baldoli, Ilaria; Tognarelli, Selene; Scaramuzzo, Rosa T; Ciantelli, Massimiliano; Cecchi, Francesca; Gentile, Marzia; Sigali, Emilio; Ghirri, Paolo; Boldrini, Antonio; Menciassi, Arianna; Laschi, Cecilia; Cuttano, Armando

    2015-02-08

    Mechanical ventilation is a therapeutic action for newborns with respiratory diseases but may have side effects. Correct equipment knowledge and training may limit human errors. We aimed to test different neonatal mechanical ventilators' performances by an acquisition module (a commercial pressure sensor plus an isolated chamber and a dedicated software). The differences (ΔP) between peak pressure values and end-expiration pressure were investigated for each ventilator. We focused on discrepancies among measured and imposed pressure data. A statistical analysis was performed. We investigated the measured/imposed ΔP relation. The ΔP do not reveal univocal trends related to ventilation setting parameters and the data distributions were non-Gaussian. Measured ΔP represent a significant parameter in newborns' ventilation, due to the typical small volumes. The investigated ventilators showed different tendencies. Therefore, a deep specific knowledge of the intensive care devices is mandatory for caregivers to correctly exploit their operating principles.

  7. Application of CPM procedures in mine ventilation

    International Nuclear Information System (INIS)

    Wang, Y.J.; Mutmansky, J.M.

    1982-01-01

    Mine ventilation analysis is an engineering discipline that can be considered a branch of the body of science known as network analysis. Likewise, the group of engineering procedures known as the critical path method (CPM) is considered a branch of network analysis. It is therefore not surprising that mine ventilation network analysis and CPM have many similarities. These similarities are useful in analyzing several types of mine ventilation problems and will be utilized in this paper. The analogy between the free split in a ventilation circuit and the critical path in a scheduling network has been recognized by Owili-Eger (1973). While this was recognized as a property of a general ventilation network, many important applications to controlled-splitting problems also exist. The mathematical procedures necessary to apply CPM and network methods have previously been presented (Wang, 1981; Wang, 1982). This paper will illustrate the implementation of these methods by application to mine ventilation networks

  8. Modelling of Natural and Hybrid Ventilation

    OpenAIRE

    Heiselberg, Per

    2006-01-01

    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,...

  9. Prevention of ventilator-associated pneumonia

    OpenAIRE

    J. Oliveira; C. Zagalo; P. Cavaco-Silva

    2014-01-01

    Invasive mechanical ventilation (IMV) represents a risk factor for the development of ventilator-associated pneumonia (VAP), which develops at least 48 h after admission in patients ventilated through tracheostomy or endotracheal intubation. VAP is the most frequent intensive-care-unit (ICU)-acquired infection among patients receiving IMV. It contributes to an increase in hospital mortality, duration of MV and ICU and length of hospital stay. Therefore, it worsens the condition of the critica...

  10. 46 CFR 153.312 - Ventilation system standards.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ventilation system standards. 153.312 Section 153.312... Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation system must meet the following: (a) A ventilation system exhaust duct must discharge no less than 10 m...

  11. Enhancement of natural ventilation in buildings using a thermal chimney

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Ho [University of California at Berkeley, Berkeley, CA (United States); Strand, Richard K. [University of Illinois at Urbana-Champaign, Champaign, IL (United States)

    2009-06-15

    A new module was developed for and implemented in the EnergyPlus program for the simulation and determination of the energy impact of thermal chimneys. This paper describes the basic concepts, assumptions, and algorithms implemented into the EnergyPlus program to predict the performance of a thermal chimney. Using the new module, the effects of the chimney height, solar absorptance of the absorber wall, solar transmittance of the glass cover and the air gap width are investigated under various conditions. Chimney height, solar absorptance and solar transmittance turned out to have more influence on the ventilation enhancement than the air gap width. The potential energy impacts of a thermal chimney under three different climate conditions are also investigated. It turned out that significant building cooling energy saving can be achieved by properly employing thermal chimneys and that they have more potential for cooling than for heating. In addition, the performance of a thermal chimney was heavily dependent on the climate of the location. (author)

  12. Short-term airing by natural ventilation

    DEFF Research Database (Denmark)

    Perino, Marco; Heiselberg, Per

    2009-01-01

    The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates traditio......The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates...... 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....

  13. A NEW EXHAUST VENTILATION SYSTEM DESIGN SOFTWARE

    Directory of Open Access Journals (Sweden)

    H. Asilian Mahabady

    2007-09-01

    Full Text Available A Microsoft Windows based ventilation software package is developed to reduce time-consuming and boring procedure of exhaust ventilation system design. This program Assure accurate and reliable air pollution control related calculations. Herein, package is tentatively named Exhaust Ventilation Design Software which is developed in VB6 programming environment. Most important features of Exhaust Ventilation Design Software that are ignored in formerly developed packages are Collector design and fan dimension data calculations. Automatic system balance is another feature of this package. Exhaust Ventilation Design Software algorithm for design is based on two methods: Balance by design (Static pressure balance and design by Blast gate. The most important section of software is a spreadsheet that is designed based on American Conference of Governmental Industrial Hygienists calculation sheets. Exhaust Ventilation Design Software is developed so that engineers familiar with American Conference of Governmental Industrial Hygienists datasheet can easily employ it for ventilation systems design. Other sections include Collector design section (settling chamber, cyclone, and packed tower, fan geometry and dimension data section, a unit converter section (that helps engineers to deal with units, a hood design section and a Persian HTML help. Psychometric correction is also considered in Exhaust Ventilation Design Software. In Exhaust Ventilation Design Software design process, efforts are focused on improving GUI (graphical user interface and use of programming standards in software design. Reliability of software has been evaluated and results show acceptable accuracy.

  14. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  15. Assessment of the Economic and Environmental Impact of Double Glazed Façade Ventilation Systems in Mediterranean Climates

    Directory of Open Access Journals (Sweden)

    Pere Alavedra

    2013-09-01

    Full Text Available Free convection is the most often used method in order to reduce solar load gains on a building with double glazed façades (DGFs. However, depending on the climate factors, the thermal performance of a DGF may not be satisfactory and extra energy costs are required to obtain suitable comfort conditions inside the building. Forced ventilation systems are a feasible alternative to improve the thermal performance of a DGF in Mediterranean climates where large solar gains are a permanent condition throughout the year. In this paper the feasibility of using diverse forced ventilation methods in DGF is evaluated. In addition, an economical comparison between different mechanical ventilation systems was performed in order to demonstrate the viability of DGF forced ventilation. Moreover, an environmental study was carried out to prove the positive energetic balance on cooling loads between free and forced convection in DGF for Mediterranean climates. For this investigation, a CFD model was used to simulate the thermal conditions in a DGF for the different ventilation systems. Results obtained for heat flux, temperature and reductions in solar load gains were analyzed and applied for the economic and environmental research.

  16. [Alveolar ventilation and recruitment under lung protective ventilation].

    Science.gov (United States)

    Putensen, Christian; Muders, Thomas; Kreyer, Stefan; Wrigge, Hermann

    2008-11-01

    Goal of mechanical ventilation is to improve gas exchange and reduce work of breathing without contributing to further lung injury. Besides providing adequate EELV and thereby arterial oxygenation PEEP in addition to a reduction in tidal volume is required to prevent cyclic alveolar collapse and tidal recruitment and hence protective mechanical ventilation. Currently, there is no consensus if and if yes at which price alveolar recruitment with high airway pressures should be intended ("open up the lung"), or if it is more important to reduce the mechanical stress and strain to the lungs as much as possible ("keep the lung closed"). Potential of alveolar recruitment differs from patient to patient but also between lung regions. Potential for recruitment depends probably more on regional lung mechanics - especially on lung elastance - than on the underlying disease. Based on available data neither high PEEP nor other methods used for alveolar recruitment could demonstrate a survival benefit in patients with ARDS. These results may support an individualized titration of PEEP or other manoeuvres used for recruitment taking into consideration the regional effects. Bedside imaging techniques allowing titration of PEEP or other manoeuvres to prevent end-expiratory alveolar collapse (tidal recruitment) and inspiratory overinflation may be a promising development.

  17. 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...

  18. Boundary conditions for the use of personal ventilation over mixing ventilation in open plan offices

    DEFF Research Database (Denmark)

    Petersen, Steffen; Hviid, Christian Anker

    2013-01-01

    This paper investigates the boundary conditions for choosing a combined Personal Ventilation (PV) and Mixing Ventilation (MV) over conventional mixing ventilation in an office with multiple workers. A simplified procedure for annual performance assessment of PV/MV systems in terms of air quality...

  19. Solar energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role solar energy may have in the energy future of the US. The topics discussed in the chapter include the solar resource, solar architecture including passive solar design and solar collectors, solar-thermal concentrating systems including parabolic troughs and dishes and central receivers, photovoltaic cells including photovoltaic systems for home use, and environmental, health and safety issues

  20. Passive solar offices: integrated design

    Energy Technology Data Exchange (ETDEWEB)

    Evans, B

    1992-05-06

    Passive solar design in out-of-town offices can remove the need for air-conditioning by making greater use of daylight and natural ventilation. To promote the use of passive solar energy a series of design studies are being run by the Energy Technology Support Unit on behalf of the Department of Energy. The three reported here are designs for out-of-town business buildings. Each is a hypothetical building designed to a realistic brief for an organisation taking the role of real client. (author).