They're heating up: Internet search query trends reveal significant public interest in heat-not-burn tobacco products.

Science.gov (United States)

Caputi, Theodore L; Leas, Eric; Dredze, Mark; Cohen, Joanna E; Ayers, John W

2017-01-01

Heat-not-burn tobacco products, battery powered devices that heat leaf tobacco to approximately 500 degrees Fahrenheit to produce an inhalable aerosol, are being introduced in markets around the world. Japan, where manufacturers have marketed several heat-not-burn brands since 2014, has been the focal national test market, with the intention of developing global marketing strategies. We used Google search query data to estimate, for the first time, the scale and growth potential of heat-not-burn tobacco products. Average monthly searches for heat-not-burn products rose 1,426% (95%CI: 746,3574) between their first (2015) and second (2016) complete years on the market and an additional 100% (95%CI: 60, 173) between the products second (2016) and third years on the market (Jan-Sep 2017). There are now between 5.9 and 7.5 million heat-not-burn related Google searches in Japan each month based on September 2017 estimates. Moreover, forecasts relying on the historical trends suggest heat-not-burn searches will increase an additional 32% (95%CI: -4 to 79) during 2018, compared to current estimates for 2017 (Jan-Sep), with continued growth thereafter expected. Contrasting heat-not-burn's rise in Japan to electronic cigarettes' rise in the United States we find searches for heat-not-burn eclipsed electronic cigarette searches during April 2016. Moreover, the change in average monthly queries for heat-not-burn in Japan between 2015 and 2017 was 399 (95% CI: 184, 1490) times larger than the change in average monthly queries for electronic cigarettes in the Unites States over the same time period, increasing by 2,956% (95% CI: 1729, 7304) compared to only 7% (95% CI: 3,13). Our findings are a clarion call for tobacco control leaders to ready themselves as heat-not-burn tobacco products will likely garner substantial interest as they are introduced into new markets. Public health practitioners should expand heat-not-burn tobacco product surveillance, adjust existing tobacco

Cascade heat recovery with coproduct gas production

Science.gov (United States)

Brown, W.R.; Cassano, A.A.; Dunbobbin, B.R.; Rao, P.; Erickson, D.C.

1986-10-14

A process for the integration of a chemical absorption separation of oxygen and nitrogen from air with a combustion process is set forth wherein excess temperature availability from the combustion process is more effectively utilized to desorb oxygen product from the absorbent and then the sensible heat and absorption reaction heat is further utilized to produce a high temperature process stream. The oxygen may be utilized to enrich the combustion process wherein the high temperature heat for desorption is conducted in a heat exchange preferably performed with a pressure differential of less than 10 atmospheres which provides considerable flexibility in the heat exchange. 4 figs.

Production of molten UO2 pools by internal heating: apparatus and preliminary experimental heat transfer results

International Nuclear Information System (INIS)

Chasanov, M.G.; Gunther, W.H.; Baker, L. Jr.

1977-01-01

The capability for removal of heat from a pool of molten fuel under postaccident conditions is an important consideration in liquid-metal fast breeder reactor safety analysis. No experimental data for pool heat transfer from molten UO 2 under conditions simulating internal heat generation by fission product decay have been reported previously in the literature. An apparatus to provide such data was developed and used to investigate heat transfer from pools containing up to 7.5 kg of UO 2 ; the internal heat generation rates and pool depths attained cover most of the ranges of interest for postaccident heat removal analysis. It was also observed in these studies that the presence of simulated fission products corresponding to approximately 150,000 kW-day/kg burnup had no significant effect on the observed heat transfer

The competitiveness of biofuels in heat and power production

International Nuclear Information System (INIS)

Kosunen, P.; Leino, P.

1995-01-01

The paper showed that natural gas is the most competitive fuel in all the energy production alternatives under review, ie both in separate heat production and electricity generation and in combined heat and power production. Even though the heavy fuel oil taxes have grown more rapidly than taxes on domestic fuels, oil continues to be cheaper than solid fuels in heating and steam plants. According to the feasibility calculations made, combined heat and power production is the least-cost production form of electricity, and the larger the plant unit, the lower the cost. Looking to the future, in respect of merely the development in fuel taxes the competitiveness of domestic fuels will improve markedly if the taxation structure remains unchanged. It seems that at smaller points of consumption, such as heating and steam plants and small-scale power plants, fuel chips would be the most competitive fuel. In larger units, such as heat and power production plants and condensing power plants, fuel peat, primarily milled peat, would be the most competitive. The competitiveness of fuel chips at larger plants will probably be limited by the supply of sufficient volumes from such an area where the delivery costs would not raise the price of fuel chips too high. Coal would remain competitive only if the real import price of coal rose clearly more slowly than the real prices of domestic fuels. It seems that heavy fuel oil will be used only as a start-up, support and back-up fuel. Evaluating the future competitiveness of natural gas is difficult, since the impact of new pipeline investments on the price of natural gas is not known

Multi-annual planning of investments for heat production. 2009 - 2020 period

International Nuclear Information System (INIS)

2005-01-01

A new Multi-annual Planning of Investments (PPI) for heat production in France has been realized in order to meet the conclusions of the Grenelle Environnement Forum for a better energy efficiency and a larger use of renewable energies. Based on quantitative data (the increase in heat production will reach more than 10 Mtoe by 2020), potential objectives have been assessed for the various heat production sources and techniques: wood, biomass (for buildings, district heating, industry and processes, cogeneration), deep and intermediary geothermal energy, individual heat pumps, individual and collective heat solar systems, biogas, etc. These objectives are said to be ambitious but reachable if every sources and techniques are thoroughly exploited

Advances in the optimisation of apparel heating products: A numerical approach to study heat transport through a blanket with an embedded smart heating system

International Nuclear Information System (INIS)

Neves, S.F.; Couto, S.; Campos, J.B.L.M.; Mayor, T.S.

2015-01-01

The optimisation of the performance of products with smart/active functionalities (e. g. in protective clothing, home textiles products, automotive seats, etc.) is still a challenge for manufacturers and developers. The aim of this study was to optimise the thermal performance of a heating product by a numerical approach, by analysing several opposing requirements and defining solutions for the identified limitations, before the construction of the first prototype. A transfer model was developed to investigate the transport of heat from the skin to the environment, across a heating blanket with an embedded smart heating system. Several parameters of the textile material and of the heating system were studied, in order to optimise the thermal performance of the heating blanket. Focus was put on the effects of thickness and thermal conductivity of each layer, and on parameters associated with the heating elements, e.g. position of the heating wires relative to the skin, distance between heating wires, applied heating power, and temperature range for operation of the heating system. Furthermore, several configurations of the blanket (and corresponding heating powers) were analysed in order to minimise the heat loss from the body to the environment, and the temperature distribution along the skin. The results show that, to ensure an optimal compromise between the thermal performance of the product and the temperature oscillation along its surface, the distance between the wires should be small (and not bigger than 50 mm), and each layer of the heating blanket should have a specific thermal resistance, based on the expected external conditions during use and the requirements of the heating system (i.e. requirements regarding energy consumption/efficiency and capacity to effectively regulate body exchanges with surrounding environment). The heating system should operate in an ON/OFF mode based on the body heating needs and within a temperature range specified based on

Implementation of heat production and storage technology and devices in power systems

International Nuclear Information System (INIS)

Romanovsky, G.; Mutale, J.

2012-01-01

Implementation of heat storage devices and technologies at power generation plants is a promising way to provide more efficient use of natural energy resources. Heat storage devices can partly replace conventional heating technologies (such as direct use of fossil fuels) during peak energy demand or in the situations where heat and electricity supply and demand do not coincide and to obtain low cost heat energy which can be further transmitted to industrial, commercial and domestic consumers. This paper presents the innovative Heat Production and Storage Device and its application at conventional, nuclear and renewable power generation plants for optimization and balancing of electricity grids. The Heat Production and Storage Device is a vessel type induction-immersion heat production and storage device which produces pre-heated water under pressure for heat energy conservation. Operation of this device is based on simultaneous and/or sequential action of an inductor and an immersion heater and can be easily connected to the electricity network as a single or a three phase unit. Heat energy accumulated by the Heat Production and Storage Device can be utilized in different industrial technological processes during periods of high energy prices. - Highlights: ► Heat Production and Storage Device for energy conservation within low load hours. ► Simultaneous and/or sequential operation of the inductor and immersion heater. ► Transform the energy of low frequency electrical current (50 Hz) into heat energy. ► Connection to the electricity network either in single or three phase unit. ► Heat Production and Storage Device will enhance the economic value of the system.

Compressed air production with waste heat utilization in industry

Science.gov (United States)

Nolting, E.

1984-06-01

The centralized power-heat coupling (PHC) technique using block heating power stations, is presented. Compressed air production in PHC technique with internal combustion engine drive achieves a high degree of primary energy utilization. Cost savings of 50% are reached compared to conventional production. The simultaneous utilization of compressed air and heat is especially interesting. A speed regulated drive via an internal combustion motor gives a further saving of 10% to 20% compared to intermittent operation. The high fuel utilization efficiency ( 80%) leads to a pay off after two years for operation times of 3000 hr.

Heat flow study at the Chinese Continental Scientific Drilling site: Borehole temperature, thermal conductivity, and radiogenic heat production

Science.gov (United States)

He, Lijuan; Hu, Shengbiao; Huang, Shaopeng; Yang, Wencai; Wang, Jiyang; Yuan, Yusong; Yang, Shuchun

2008-02-01

The Chinese Continental Scientific Drilling (CCSD) Project offers a unique opportunity for studying the thermal regime of the Dabie-Sulu ultrahigh-pressure metamorphic belt. In this paper, we report measurements of borehole temperature, thermal conductivity, and radiogenic heat production from the 5158 m deep main hole (CCSD MH). We have obtained six continuous temperature profiles from this borehole so far. The temperature logs show a transient mean thermal gradient that has increased from 24.38 to 25.28 K km-1 over a period of about 1.5 years. We measured thermal conductivities and radiogenic heat productions on more than 400 core samples from CCSD MH. The measured thermal conductivities range between 1.71 and 3.60 W m-1 K-1, and the radiogenic heat productions vary from 0.01 μW m-3 to over 5.0 μW m-3, with a mean value of 1.23 ± 0.82 μW m-3 for the upper 5-km layer of the crust. The heat productions in CCSD MH appear to be more rock-type than depth-dependent and, over the depth range of CCSD MH, do not fit the popular model of heat production decreasing exponentially with increasing depth. The measured heat flow decreases with depth from ˜75 mW m-2 near the surface to ˜66 mW m-2 at a depth of 4600 m. High heat flow anomalies occur at ˜1000 and ˜2300 m, and low anomalies occur at 3300-4000 m. A preliminary two-dimensional numerical model suggests that both radiogenic heat production and thermal refraction due to structural heterogeneity are at least partially responsible for the vertical variation of heat flow in CCSD MH.

Permafrost thawing in organic Arctic soils accelerated by ground heat production

DEFF Research Database (Denmark)

Hollesen, Jørgen; Matthiesen, Henning; Møller, Anders Bjørn

2015-01-01

Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change1, 2. The accompanying heat production from microbial metabolism of organic material has been...... recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon3, 4. This internal heat production is poorly understood, however, and the strength of this effect remains unclear3. Here, we have quantified the variability of heat production in contrasting...... organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated...

Improved energy efficiency in juice production through waste heat recycling

International Nuclear Information System (INIS)

Anderson, J.-O.; Elfgren, E.; Westerlund, L.

2014-01-01

Highlights: • A heating system at a juice production was investigated and improved. • Different impacts of drying cycle improvements at the energy usage were explored. • The total heat use for drying could thereby be decreased with 52%. • The results point out a significant decrease of heat consumption with low investment costs. - Abstract: Berry juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds in a press cake. Traditionally, these by-products have been composted, but due to their valuable nutrients, it could be profitable to sell them instead. The skins and seeds need to be separated and dried to a moisture content of less than 10 %wt (on dry basis) in order to avoid fermentation. A berry juice plant in the north of Sweden has been studied in order to increase the energy and resource efficiency, with special focus on the drying system. This was done by means of process integration with mass and energy balance, theory from thermodynamics and psychrometry along with measurements of the juice plant. Our study indicates that the drying system could be operated at full capacity without any external heat supply using waste heat supplied from the juice plant. This would be achieved by increasing the efficiency of the dryer by recirculation of the drying air and by heat supply from the flue gases of the industrial boiler. The recirculation would decrease the need of heat in the dryer with about 52%. The total heat use for the plant could thereby be decreased from 1262 kW to 1145 kW. The improvements could be done without compromising the production quality

Dossier: renewable energies for heat production; Dossier: energies renouvelables pour la production de chaleur

Energy Technology Data Exchange (ETDEWEB)

Anon.

2002-09-01

This dossier makes a state-of-the-art of today's applications of renewable energy sources in the residential, collective and tertiary sectors for the space heating and the hot water production. In France, three energy sources profit by a particularly favorable evolution: the solar thermal, the wood fuel and the geothermal energies. In these sectors, the offer of reliable and technically achieved appliances has been considerably widen thanks to the impulse of some French and German manufacturers. Part 1 - solar thermal: individual solar water heaters (monobloc, thermosyphon with separate tank, forced circulation systems, auxiliary heating systems); combined solar systems (direct heating floor, system with storage); collective solar systems for hot water production (receivers, efficiency, heat storage and transfer, auxiliary heating, decentralized systems); heating of open-air swimming pools; some attempts in air-conditioning; the warranty of results. Part 2 - wood fuels: domestic space heating (log boilers, installation rules, hydro-accumulation, automatic boilers); collective and tertiary wood-fueled heating plants (design of boiler plants, fuel supply, combustion chamber, smoke purification systems, ash removal, regulation system), fuels for automatic collective plants, design and installation rules. Part 3 - geothermal energy: different types (water-source and ground-source heat pumps, financial incentive). (J.S.)

Power/heat production from biomass in Finland - Two modern Finnish examples

International Nuclear Information System (INIS)

Aeijaelae, M.

1997-01-01

According to this conference paper, Finland is a leading country in the utilization of biomass fuels for power and heat production. One reason is that peat and wood are the only indigenous fuels available in Finland. Other reasons are the strong forest industry and the widely adopted combined heat and power (CHP) production. CHP production is typical of process industry and municipal district heating. The most common boiler type in modern CHP plants is the fluidized bed type. District heating is the cheapest heating in municipalities with a few thousand inhabitants. Electric heating dominates in sparsely populated regions. CHP becomes attractive for populations of more than ten thousand. Two examples are described: (1) Rauhalahti Power Plant produces 140 MW of district heat, 65 MW of industrial steam and 87 MW of electricity. (2) Kuusamo Power Plant produces 6.1 MW electric energy and 17.6 MW district heat; its unique feature is the utilization of the bed mixing dryer for drying of the fuel prior to combustion, this dryer being the first of its kind in the world. 1 figure

Thermal Heat and Power Production with Models for Local and Regional Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Saether, Sturla

1999-07-01

The primary goal of this thesis is the description and modelling of combined heat and power systems as well as analyses of thermal dominated systems related to benefits of power exchange. Large power plants with high power efficiency (natural gas systems) and heat production in local heat pumps can be favourable in areas with low infrastructure of district heating systems. This system is comparable with typical combined heat and power (CHP) systems based on natural gas with respect to efficient use of fuel energy. The power efficiency obtainable from biomass and municipal waste is relatively low and the advantage of CHP for this system is high compared to pure power production with local heat pumps for heat generation. The advantage of converting pure power systems into CHP systems is best for power systems with low power efficiency and heat production at low temperature. CHP systems are divided into two main groups according to the coupling of heat and power production. Some CHP systems, especially those with strong coupling between heat and power production, may profit from having a thermal heat storage subsystem. District heating temperatures direct the heat to power ratio of the CHP units. The use of absorption chillers driven by district heating systems are also evaluated with respect to enhancing the utilisation of district heating in periods of low heat demand. Power exchange between a thermal dominated and hydropower system is found beneficial. Use of hydropower as a substitute for peak power production in thermal dominated systems is advantageous. Return of base load from the thermal dominated system to the hydropower system can balance in the net power exchange.

Heat and fission product transport in molten core material pool with crust

International Nuclear Information System (INIS)

Yun, J.I.; Suh, K.Y.; Kang, C.S.

2005-01-01

Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the reactor vessel during a severe accident. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool is estimated by product of the mass concentration and energy conversion factor of each fission product. Twenty-nine elements are chosen and classified by their chemical properties to calculate heat generation rate in the pool. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis is performed for heat and fission product transport in a molten core material pool during the Three Mile Island Unit 2 (TMI-2) accident. The pool is assumed to be a partially filled hemisphere, whose change in geometry is neglected during the numerical calculation. Calculated results indicate that the peak temperature in the molten pool is significantly lowered, since a substantial amount of the volatile fission products is released from the molten pool during progression of the accident. The results may directly be applied to the existing severe accident analysis codes to more mechanistically determine the thermal load to the reactor vessel lower head during the in-vessel retention

Heat flow and radiogenic heat production in Brazil with implications for thermal evolution of continents

International Nuclear Information System (INIS)

Vitorello, I.

1978-01-01

Heat flow and heat production results are reported from nineteen widely spaced sites in eastern and central parts of Brazil. Three sites in the stable Sao Francisco Craton comprising rocks with Transamazonic ages (2600 to 1800 Ma) or older present an average heat flow of 41.8 +- 4.6 (standard error of the mean=sem) mW m -2 , typical of shield areas; eight sites located in the Late Precambrian Braziliane metamorphic belt have an average heat flow of 54.7 +- 3.8 (sem) mW m -2 ; and four sites in the Parana basin, locus of a Late Jurassic-Early Cretaceous basaltic volcanicity, have a mean heat flow of 70.1 +- 5.9 (sem) mW m -2 . Heat flow results from the Late Cretaceous-Early Tertiary alkalic intrusion of Pocos de Caldas have yielded a site mean of 55.3 mW m -2 . These results indicate a systematic decrease of heat flow with increasing age of the last tectonothermal event. As an explanation for this pattern, a model comprising three main heat flow components is advanced: radiogenic heat from the crust (40%), with the decrease of this contribution with time being achieved by erosional removal of radioactive material; a residual heat from a transient thermal perturbation associated with tectogenesis; and a uniform heat flow of about 28 mW m -2 from deeper sources. The Coastal Brazilian Shield is characterized by ordinary surface and reduced heat flow, but its heat production appears to be less concentrated near the surface, and distributed over a greater depth. Because of the variation in plate thickness, relative movements between the South American plate and the underlying mantle material are possibly constrained to depths exceeding 400 km

Reactors for heat production and the development of district heating in France

International Nuclear Information System (INIS)

Ricateau, P.

1977-01-01

Hitherto the development of nuclear power engineering has been based on the generation of electricity, and even of base-load electricity for feeding into a grid covering an entire country. Definition of the service to be rendered by a nuclear power station was thus extremely simple, namely to supply electricity throughout the year at the lowest possible cost and with the maximum possible reliability. Between the reactor on the one hand and the consumers on the other - consumers whose requirements are very diverse and who are geographically widely scattered - the grid forms a sort of screen so that the optimization of the reactor hardly depends at all on the configuration of the remainder of the transmission and distribution system. The production of heat involves totally different problems, for two essential reasons: (a) the limited economic range for the distribution of heat which limits the reactor to a specific group of consumers, and (b) the fact that the temperature, unlike the electrical potential, cannot be transformed at will but drops continuously between production and consumption of the heat. The temperature of the reactor must be matched to the nature of consumer demand and to the distance over which the heat must be transported. The heat balance thus appears to be like that of a system in which source, transmission and utilization are closely related. In these conditions the solutions will depend on numerous factors and one should not be surprised at finding different applications of nuclear power not only from one country to another but even from one area to another within the same country. The author first outlines the characteristics of the demand for district heating in France and then examines the types of nuclear plant which seem best suited for this purpose in the French context. (author)

Effect of heating system using a geothermal heat pump on the production performance and housing environment of broiler chickens.

Science.gov (United States)

Choi, H C; Salim, H M; Akter, N; Na, J C; Kang, H K; Kim, M J; Kim, D W; Bang, H T; Chae, H S; Suh, O S

2012-02-01

A geothermal heat pump (GHP) is a potential heat source for the economic heating of broiler houses with optimum production performance. An investigation was conducted to evaluate the effect of a heating system using a GHP on production performance and housing environment of broiler chickens. A comparative analysis was also performed between the GHP system and a conventional heating system that used diesel for fuel. In total, 34,000 one-day-old straight run broiler chicks were assigned to 2 broiler houses with 5 replicates in each (3,400 birds/replicate pen) for 35 d. Oxygen(,) CO(2), and NH(3) concentrations in the broiler house, energy consumption and cost of heating, and production performance of broilers were evaluated. Results showed that the final BW gain significantly (P heating system did not affect the mortality of chicks during the first 4 wk of the experimental period, but the mortality markedly increased in the conventional broiler house during the last wk of the experiment. Oxygen content in the broiler house during the experimental period was not affected by the heating system, but the CO(2) and NH(3) contents significantly increased (P heating the GHP house was significantly lower (P heating system for broiler chickens.

Development of small and medium reactors for power and heat production

International Nuclear Information System (INIS)

Becka, J.

1978-01-01

Data are given on the current state of development of small and medium-power reactors designed mainly for electric power production in small power grids, for heat production for small- and medium-power desalination plants with possible electric power generation, for process steam production and heat development for district heating systems, again combined with electric power generation, and for propelling big and fast passenger ships. A diagram is shown of the primary system of an integrated PWR derived from the Otto Hahn reactor. The family is listed of the standard sizes of the integral INTERATOM company pressurized water reactors. Also listed are the specifications and design of CAS 2CG and AS 3G type reactors used mainly for long-distance heating systems. (J.B.)

Cost allocation. Combined heat and power production

International Nuclear Information System (INIS)

Sidzikauskas, V.

2002-01-01

The benefits of Combined Heat and Power (CHP) generation are discussed. The include improvement in energy intensity of 1% by 2010, 85-90% efficiency versus 40-50% of condensation power and others. Share of CHP electricity production in ERRA countries is presented.Solutions for a development CHP cost allocation are considered. Conclusion are presented for CHP production cost allocation. (R.P.)

Heat production: Longitudinal versus torsional phacoemulsification.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-10-01

To compare the heat production of longitudinal versus torsional phacoemulsification under strict laboratory test conditions. Department of Ophthalmology, David Geffen School of Medicine at UCLA, and Jules Stein Eye Institute, Los Angeles, California, USA. Two Infiniti phacoemulsification handpieces were inserted into silicone test chambers filled with a balanced salt solution and imaged serially using a thermal camera. Incision compression was simulated by suspending 25.3 g weights from the silicone chambers. To simulate occlusion of the phacoemulsification tip, the aspiration line was clamped. Peak temperatures were measured 0, 10, 30, 60, and 120 seconds after the commencement of continuous ultrasound power. The 2 handpieces, operating exclusively in longitudinal or torsional modes, were compared 3 ways: (1) using the same power displayed on the instrument console, (2) using identical stroke lengths, and (3) using the same applied energy, a product of stroke length and frequency. For all 3 comparisons, torsional phacoemulsification resulted in lower temperatures at each time point. At the same displayed power setting, the scenario most familiar to cataract surgeons, longitudinal phacoemulsification elevated temperatures up to 41.5 degrees C more than torsional phacoemulsification. Torsional phacoemulsification generated less heat than longitudinal phacoemulsification in all 3 comparison tests. Lower operating temperatures indicate lower heat generation within the same volume of fluid, and this may provide additional thermal protection during cataract surgery.

Working in Australia's heat: health promotion concerns for health and productivity.

Science.gov (United States)

Singh, Sudhvir; Hanna, Elizabeth G; Kjellstrom, Tord

2015-06-01

This exploratory study describes the experiences arising from exposure to extreme summer heat, and the related health protection and promotion issues for working people in Australia. Twenty key informants representing different industry types and occupational groups or activities in Australia provided semi-structured interviews concerning: (i) perceptions of workplace heat exposure in the industry they represented, (ii) reported impacts on health and productivity, as well as (iii) actions taken to reduce exposure or effects of environmental heat exposure. All interviewees reported that excessive heat exposure presents a significant challenge for their industry or activity. People working in physically demanding jobs in temperatures>35°C frequently develop symptoms, and working beyond heat tolerance is common. To avoid potentially dangerous health impacts they must either slow down or change their work habits. Such health-preserving actions result in lost work capacity. Approximately one-third of baseline work productivity can be lost in physically demanding jobs when working at 40°C. Employers and workers consider that heat exposure is a 'natural hazard' in Australia that cannot easily be avoided and so must be accommodated or managed. Among participants in this study, the locus of responsibility for coping with heat lay with the individual, rather than the employer. Heat exposure during Australian summers commonly results in adverse health effects and productivity losses, although quantification studies are lacking. Lack of understanding of the hazardous nature of heat exposure exacerbates the serious risk of heat stress, as entrenched attitudinal barriers hamper amelioration or effective management of this increasing occupational health threat. Educational programmes and workplace heat guidelines are required. Without intervention, climate change in hot countries, such as Australia, can be expected to further exacerbate heat-related burden of disease and loss

Combined heat and power production through biomass gasification with 'Heatpipe-Reformer'

International Nuclear Information System (INIS)

Iliev, I.; Kamburova, V.; Terziev, A.

2013-01-01

The current report aims is to analyze the system for combined heat and power production through biomass gasification with “heatpipe-reformer” system. Special attention is paid on the process of synthetic gas production in the Reformer, its cleaning and further burning in the co-generation unit. A financial analysis is made regarding the investments and profits generated by the combined heat and power production. (authors)

The Chemistry of Self-Heating Food Products: An Activity for Classroom Engagement

Science.gov (United States)

Oliver-Hoyo, Maria T.; Pinto, Gabriel; Llorens-Molina, Juan Antonio

2009-01-01

Two commercial self-heating food products have been used to apply chemical concepts such as stoichiometry, enthalpies of reactions and solutions, and heat transfer in a classroom activity. These products are the self-heating beverages sold in Europe and the Meals, Ready to Eat or MREs used primarily by the military in the United States. The main…

NGNP Process Heat Applications: Hydrogen Production Accomplishments for FY2010

Energy Technology Data Exchange (ETDEWEB)

Charles V Park

2011-01-01

This report summarizes FY10 accomplishments of the Next Generation Nuclear Plant (NGNP) Engineering Process Heat Applications group in support of hydrogen production technology development. This organization is responsible for systems needed to transfer high temperature heat from a high temperature gas-cooled reactor (HTGR) reactor (being developed by the INL NGNP Project) to electric power generation and to potential industrial applications including the production of hydrogen.

Plasma Production and Heating in the Superconducting Levitron

Energy Technology Data Exchange (ETDEWEB)

Anderson, O. A.; Birdsall, D. H.; Hartman, C. W.; Hooper, Jr., E. B.; Munger, R. H.; Taylor, C. E. [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1971-10-15

Plasma production and heating in the Superconducting Levitron are described. The device has a floating superconducting ring with 40-cm major radius and 5-cm minor radius, which carries up to 600 kA current. Toroidal field is provided by a current of up to 1 MA. Six poloidal field coils are used to shape the magnetic surfaces to obtain field configurations with strong shear and with minimum average B, a local minimum -B well, or minimum {partial_derivative}B/{partial_derivative}s ({delta}B/B Less-Than-Or-Equivalent-To 0.005 - 0.05). Large area surfaces at liquid helium temperature which are not directly exposed to the plasma provide ultrahigh vacuum. Methods of production and heating of dense plasma with appreciable {beta} have been studied using a classical diffusion and thermal conduction model, which includes trapped-particle effects. Computations have been made both for heating by an initial hot electron plasma and for energetic neutral injection. The latter technique yields n Almost-Equal-To 10{sup 13} cm{sup -3}, T{sub e} Almost-Equal-To T{sub i} Almost-Equal-To 0.3 to 0.8 keV with existing sources (200 mA equivalent current at 2 keV). Production and heating by energetic electrons proceeds in two steps: First, a hot electron plasma with n Almost-Equal-To 10{sup 11} to 10{sup 13} cm{sup -3}, T{sub e}, hot Almost-Equal-To 100 to 500 keV is established by electron cyclotron resonance heating (ECRH). Second, dense plasma is formed by injection of a short pulse (50 {mu}s) of neutral gas. The inherent cutoff limit of direct ECRH is thereby overcome. Numerical computations of the subsequent in situ heating by energetic electrons predict T{sub i} = 0,14 to 2.0 keV, n = 5 x 10{sup 13} to 10{sup 14} cm{sup -3} for B{sub poloidal} = 1.5 to 6 kG. Thus, heating and ion temperatures comparable to or greater than obtained in the Tokamak T-3 device are predicted. This technique allows scaling to ignition temperature for a D-T plasma using available microwave power sources and

Induction heating in in-line strip production process

International Nuclear Information System (INIS)

Costa, P.; Santinelli, M.

1995-05-01

ISP (In-line Strip Production), a continuous process for steel strip production, has recently been set in an italian innovative plant, where ecological impact and power requirements are lighter than usual. This report describes the studies performed by ENEA (Italian Agency for New Technologies, Energy and the Environment), while a prototype reheating facility was arranged by Acciaieria ISP in Cremona (Italy). The authors, after a study of the prototype electromagnetic field, calculate the heating rate, with the thermal network method. Then they detect, with a 1-D-FEM, the heat diffusion through the strip cross section. Afterward, since the heat distribution depends on the eddy current density one, which is given by the magnetic field distribution, the authors, with a 3-D-FEM, carry out a coupled, electromagnetic and thermal, analysis in time domain. The strip temperature map is established by the balance between skin depth heating and surface cooling: a thermal analysis, performed with a moving 2-D-FEM, take into account the effects of the different heating and cooling situations, originated by the strip moving at a speed of 6m/min through four consecutive reheating facilities. The temperatures of a strip sample heated by the prototype have been monitored, acquired by a computer and related with the simulation results. The little difference between experiment and simulation assessed the qualitative and quantitative validity of this analysis, that has come out to be a tool, useful to evaluate the effects of possible improvements to the ISP process

Analysis of carbon monoxide production in multihundred-watt heat sources

International Nuclear Information System (INIS)

Peterson, D.E.; Mulford, R.N.R.

1976-05-01

The production of carbon monoxide observed within Multihundred Watt heat sources placed under storage conditions was analyzed. Results of compositional and isotopic analyses of gas taps performed on eight heat sources are summarized and interpreted. Several proposed CO generation mechanisms are examined theoretically and assessed by applying thermodynamic principles. Outgassing of the heat source graphite followed by oxygen isotopic exchange through the vent assemblies appears to explain the CO production at storage temperatures. Reduction of the plutonia fuel sphere by the CO is examined as a function of temperature and stoichiometry. Experiments that could be performed to investigate possible CO generation mechanisms are discussed

Assessment of heat treatment of dairy products by MALDI-TOF-MS.

Science.gov (United States)

Meltretter, Jasmin; Birlouez-Aragon, Inès; Becker, Cord-Michael; Pischetsrieder, Monika

2009-12-01

The formation of the Amadori product from lactose (protein lactosylation) is a major parameter to evaluate the quality of processed milk. Here, MALDI-TOF-MS was used for the relative quantification of lactose-adducts in heated milk. Milk was heated at a temperature of 70, 80, and 100 degrees C between 0 and 300 min, diluted, and subjected directly to MALDI-TOF-MS. The lactosylation rate of alpha-lactalbumin increased with increasing reaction temperature and time. The results correlated well with established markers for heat treatment of milk (concentration of total soluble protein, soluble alpha-lactalbumin and beta-lactoglobulin at pH 4.6, and fluorescence of advanced Maillard products and soluble tryptophan index; r=0.969-0.997). The method was also applied to examine commercially available dairy products. In severely heated products, protein pre-purification by immobilized metal affinity chromatography improved spectra quality. Relative quantification of protein lactosylation by MALDI-TOF-MS proved to be a very fast and reliable method to monitor early Maillard reaction during milk processing.

Defining and evaluating heat stress thresholds in different dairy cow production systems

OpenAIRE

Brügemann, Kerstin; Gernand, Erhard; König von Borstel, Uta; König, Sven

2012-01-01

The aim of this study was to assess the impact of heat stress in dairy cows on test-day records for production traits and somatic cell score (SCS) in the state of Lower Saxony, Germany. Three different production systems were defined: A production system characterized by intensive crop production (=indoor housing), a pasture based production system, and a maritime region. Heat stress was assessed by two temperature-humidity indices (THI) modelled as random regression coefficients in an analys...

A mathematical model of heat flow in a thermopile for measuring muscle heat production: implications for design and signal analysis.

Science.gov (United States)

Barclay, C J

2015-09-01

Contracting muscles produce heat which largely arises from the biochemical reactions that provide the energy for contraction. Measurements of muscle heat production have made, and continue to make, important contributions to our understanding of the bases of contraction. Most measurements of muscle heat production are made using a thermopile, consisting of a series of thermocouples arranged so that alternate thermocouples are in thermal contact with the muscle and with an isothermal reference. In this study, a mathematical model was constructed of a muscle lying on a thermopile consisting of antimony-bismuth thermocouples sandwiched between polymer sheets. The validity of the model was demonstrated by its ability to accurately predict thermopile outputs in response to applying heat to the thermopile surface, to generating heat in the thermocouples using the Peltier effect and to adding heat capacity on the thermopile surface. The model was then used to show how practical changes to thermopile construction could minimise response time and thermopile heat capacity and allow measurement of very low rates of heat production. The impulse response of a muscle-thermopile system was generated using the model and used to illustrate how a measured signal can be deconvolved with the impulse response to correct for lag introduced by the thermopile.

Heat and Fission Product Transport in a Molten U-Zr-O Pool With Crust

International Nuclear Information System (INIS)

Yun, J.I.; Suh, K.Y.; Kang, C.S.

2002-01-01

Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the pool. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool was estimated by product of the mass concentration and energy conversion factor of each fission product. For the calculation of heat generation rate in the pool, twenty-nine elements were chosen and classified by their chemical properties. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis was performed for the TMI-2 accident. The pool is assumed to be a partially filled hemispherical geometry and the change of pool geometry during the numerical calculation was neglected. Results of the numerical calculation revealed that the peak temperature of the molten pool significantly decreased and most of the volatile fission products were released from the molten pool during the accident. (authors)

Crustal heat production and estimate of terrestrial heat flow in central East Antarctica, with implications for thermal input to the East Antarctic ice sheet

Science.gov (United States)

Goodge, John W.

2018-02-01

Terrestrial heat flow is a critical first-order factor governing the thermal condition and, therefore, mechanical stability of Antarctic ice sheets, yet heat flow across Antarctica is poorly known. Previous estimates of terrestrial heat flow in East Antarctica come from inversion of seismic and magnetic geophysical data, by modeling temperature profiles in ice boreholes, and by calculation from heat production values reported for exposed bedrock. Although accurate estimates of surface heat flow are important as an input parameter for ice-sheet growth and stability models, there are no direct measurements of terrestrial heat flow in East Antarctica coupled to either subglacial sediment or bedrock. As has been done with bedrock exposed along coastal margins and in rare inland outcrops, valuable estimates of heat flow in central East Antarctica can be extrapolated from heat production determined by the geochemical composition of glacial rock clasts eroded from the continental interior. In this study, U, Th, and K concentrations in a suite of Proterozoic (1.2-2.0 Ga) granitoids sourced within the Byrd and Nimrod glacial drainages of central East Antarctica indicate average upper crustal heat production (Ho) of about 2.6 ± 1.9 µW m-3. Assuming typical mantle and lower crustal heat flux for stable continental shields, and a length scale for the distribution of heat production in the upper crust, the heat production values determined for individual samples yield estimates of surface heat flow (qo) ranging from 33 to 84 mW m-2 and an average of 48.0 ± 13.6 mW m-2. Estimates of heat production obtained for this suite of glacially sourced granitoids therefore indicate that the interior of the East Antarctic ice sheet is underlain in part by Proterozoic continental lithosphere with an average surface heat flow, providing constraints on both geodynamic history and ice-sheet stability. The ages and geothermal characteristics of the granites indicate that crust in central

Wood Degradation by Thermotolerant and Thermophilic Fungi for Sustainable Heat Production

NARCIS (Netherlands)

Caizan Juanarena, Leire; ter Heijne, Annemiek; Buisman, Cees; Van der Wal, A.

2016-01-01

The use of renewable biomass for production of heat and electricity plays an important role in the circular economy. Degradation of wood biomass to produce heat is a clean and novel process proposed as an alternative to wood burning, and could be used for various heating applications. So far, wood

Solar Water Heating System for Biodiesel Production

Directory of Open Access Journals (Sweden)

Syaifurrahman

2018-01-01

Full Text Available Nowadays, electricity become very expensive thing in some remote areas. Energy from solar panels give the solution as renewable energy that is environment friendly. West Borneo is located on the equator where the sun shines for almost 10-15 hours/day. Solar water heating system which is includes storage tank and solar collections becomes a cost-effective way to generate the energy. Solar panel heat water is delivered to water in storage tank. Hot water is used as hot fluid in biodiesel jacked reactor. The purposes of this research are to design Solar Water Heating System for Biodiesel Production and measure the rate of heat-transfer water in storage tank. This test has done for 6 days, every day from 8.30 am until 2.30 pm. Storage tank and collection are made from stainless steel and polystyrene a well-insulated. The results show that the heater can be reach at 50ºC for ±2.5 hours and the maximum temperature is 62ºC where the average of light intensity is 1280 lux.

Solar Water Heating System for Biodiesel Production

Science.gov (United States)

Syaifurrahman; Usman, A. Gani; Rinjani, Rakasiwi

2018-02-01

Nowadays, electricity become very expensive thing in some remote areas. Energy from solar panels give the solution as renewable energy that is environment friendly. West Borneo is located on the equator where the sun shines for almost 10-15 hours/day. Solar water heating system which is includes storage tank and solar collections becomes a cost-effective way to generate the energy. Solar panel heat water is delivered to water in storage tank. Hot water is used as hot fluid in biodiesel jacked reactor. The purposes of this research are to design Solar Water Heating System for Biodiesel Production and measure the rate of heat-transfer water in storage tank. This test has done for 6 days, every day from 8.30 am until 2.30 pm. Storage tank and collection are made from stainless steel and polystyrene a well-insulated. The results show that the heater can be reach at 50ºC for ±2.5 hours and the maximum temperature is 62ºC where the average of light intensity is 1280 lux.

Ruminant Nutrition Symposium: ruminant production and metabolic responses to heat stress.

Science.gov (United States)

Baumgard, L H; Rhoads, R P

2012-06-01

Heat stress compromises efficient animal production by marginalizing nutrition, management, and genetic selection efforts to maximize performance endpoints. Modifying farm infrastructure has yielded modest success in mitigating heat stress-related losses, yet poor production during the summer remains arguably the costliest issue facing livestock producers. Reduced output (e.g., milk yield and muscle growth) during heat stress was traditionally thought to result from decreased nutrient intake (i.e., a classic biological response shared by all animals during environmental-induced hyperthermia). Our recent observations have begun to challenge this belief and indicate heat-stressed animals employ novel homeorhetic strategies to direct metabolic and fuel selection priorities independently of nutrient intake or energy balance. Alterations in systemic physiology support a shift in carbohydrate metabolism, evident by increased basal and stimulated circulating insulin concentrations. Perhaps most intriguing given the energetic shortfall of the heat-stressed animal is the apparent lack of basal adipose tissue mobilization coupled with a reduced responsiveness to lipolytic stimuli. Thus, the heat stress response markedly alters postabsorptive carbohydrate, lipid, and protein metabolism independently of reduced feed intake through coordinated changes in fuel supply and utilization by multiple tissues. Interestingly, the systemic, cellular, and molecular changes appear conserved amongst different species and physiological states. Ultimately, these changes result in the reprioritization of fuel selection during heat stress, which appears to be primarily responsible for reduced ruminant animal productivity during the warm summer months.

Effects of obesity on body temperature in otherwise-healthy females when controlling hydration and heat production during exercise in the heat.

Science.gov (United States)

Adams, J D; Ganio, Matthew S; Burchfield, Jenna M; Matthews, Andy C; Werner, Rachel N; Chokbengboun, Amanda J; Dougherty, Erin K; LaChance, Alex A

2015-01-01

Previous studies investigating body temperature responses in obese individuals during exercise in the heat fail to control metabolic heat production or hydration status during exercise. To determine if there are differences in body temperature responses between obese and non-obese females when controlling metabolic heat production during exercise. Twenty healthy females, ten obese (43.5 ± 4.5 % fat, 77.5 ± 14.4 kg) and ten non-obese (26.3 ± 6.2 % fat, 53.7 ± 6.4 kg), cycled for 60 min in a warm environment (40 °C, 30 % humidity) at a work load that elicited either 300 W of metabolic heat production (fixed heat production; FHP) or 175 W/m(2) of skin surface area (body surface area, BSA). Before and during exercise, rectal temperature (T re), mean skin temperature (T sk), oxygen uptake (VO2), and sweat rate were measured. Fluid was provided throughout exercise so that euhydration was maintained throughout. In the FHP trial, when absolute heat production was similar between obese (287 ± 15 W) and non-obese (295 ± 18 W) individuals (P > 0.05), there were no differences at the end of exercise in T re (38.26 ± 0.40 vs. 38.30 ± 0.30 °C, respectively) or T sk (36.94 ± 1.65 vs. 35.85 ± 0.67 °C) (all P > 0.05). In the BSA trials, relative heat production was similar between obese and non-obese individuals (168 ± 8 vs. 176 ± 5 W/m(2), respectively; P > 0.05). Similar to the FHP trials, there were no differences between obese and non-obese T re (38.45 ± 0.33 vs. 38.08 ± 0.29 °C, respectively) or T sk (36.82 ± 1.04 vs. 36.11 ± 0.64 °C) at the end of exercise (all P > 0.05). When obese and non-obese females exercised at a fixed metabolic heat production and euhydration was maintained, there were no differences in body temperature between groups.

Modelling temperature-dependent heat production over decades in High Arctic coal waste rock piles

DEFF Research Database (Denmark)

Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.

2011-01-01

Subsurface heat production from oxidation of pyrite is an important process that may increase subsurface temperatures within coal waste rock piles and increase the release of acid mine drainage, AMD. Waste rock piles in the Arctic are especially vulnerable to changes in subsurface temperatures...... such as heat production from coal oxidation may be equally important....... as the release of AMD normally is limited by permafrost. Here we show that temperatures within a 20 year old heat-producing waste rock pile in Svalbard (78°N) can be modelled by the one-dimensional heat and water flow model (CoupModel) with a new temperature-dependent heat-production module that includes both...

Heat production during contraction in skeletal muscle of hypothyroid mice

Energy Technology Data Exchange (ETDEWEB)

Leijendekker, W.J.; van Hardeveld, C.; Elzinga, G. (Free Univ., Amsterdam (Netherlands))

1987-08-01

The effect of hypothyroidism on tension-independent and -dependent heat produced during a twitch and a tetanic contraction of extensor digitorum longus (EDL) and soleus muscle of mice was examined. The amount of heat produced during a twitch and the rate of heat development during a tetanus of EDL and soleus were measured at and above optimal length. The effect of hypothyroidism on force production was <30%. Straight lines were used to fit the relation between heat production and force. Hypothyroidism significantly decreases tension-independent heat during contraction of EDL and soleus muscle. Because the tension-independent heat is considered to be related to the Ca{sup 2+} cycling, these findings suggest that ATP splitting due to the Ca{sup 2+} cycling is reduced in hypothyroid mice. This conclusion was strengthened by the observation that the oxalate-supported {sup 45}Ca{sup 2+}-uptake activity and {sup 45}Ca{sup 2+}-loading capacity of muscle homogenates from hypothyroid mice were reduced, respectively, to 51 and to 65% in soleus and to 63 and 73% in EDL muscle as compared with euthyroid mice. The tension-dependent rate of heat development during a tetanus was also decreased in soleus muscle of hypothyroid mice. This suggests a lower rate of ATP hydrolysis related to cross-bridge cycling in this muscle due to the hypothyroid state.

Local business models for district heat production; Kaukolaemmoen paikalliset liiketoimintamallit

Energy Technology Data Exchange (ETDEWEB)

Hakala, L.; Pesola, A.; Vanhanen, J.

2012-12-15

Local district heating business, outside large urban centers, is a profitable business in Finland, which can be practiced with several different business models. In addition to the traditional, local district heating business, local district heat production can be also based on franchising business model, on integrated service model or on different types of cooperation models, either between a local district heat producer and industrial site providing surplus heat or between a local district heat producer and a larger district heating company. Locally available wood energy is currently utilized effectively in the traditional district heating business model, in which a local entrepreneur produces heat to consumers in the local area. The franchising model is a more advanced version of the traditional district heating entrepreneurship. In this model, franchisor funds part of the investments, as well as offers centralized maintenance and fuel supply, for example. In the integrated service model, the local district heat producer offers also energy efficiency services and other value-added services, which are based on either the local district heat suppliers or his partner's expertise. In the cooperation model with industrial site, the local district heating business is based on the utilization of the surplus heat from the industrial site. In some cases, profitable operating model approach may be a district heating company outsourcing operations of one or more heating plants to a local entrepreneur. It can be concluded that all business models for district heat production (traditional district heat business model, franchising, integrated service model, cooperative model) discussed in this report can be profitable in Finnish conditions, as well for the local heat producer as for the municipality - and, above all, they produce cost-competitive heat for the end-user. All the models were seen as viable and interesting and having possibilities for expansion Finland

Biodiesel production process from microalgae oil by waste heat recovery and process integration.

Science.gov (United States)

Song, Chunfeng; Chen, Guanyi; Ji, Na; Liu, Qingling; Kansha, Yasuki; Tsutsumi, Atsushi

2015-10-01

In this work, the optimization of microalgae oil (MO) based biodiesel production process is carried out by waste heat recovery and process integration. The exergy analysis of each heat exchanger presented an efficient heat coupling between hot and cold streams, thus minimizing the total exergy destruction. Simulation results showed that the unit production cost of optimized process is 0.592$/L biodiesel, and approximately 0.172$/L biodiesel can be avoided by heat integration. Although the capital cost of the optimized biodiesel production process increased 32.5% and 23.5% compared to the reference cases, the operational cost can be reduced by approximately 22.5% and 41.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heat transfer study on open heat exchangers used in jaggery production modules – Computational Fluid Dynamics simulation and field data assessment

International Nuclear Information System (INIS)

La Madrid, Raul; Marcelo, Daniel; Orbegoso, Elder Mendoza; Saavedra, Rafael

2016-01-01

Highlights: • Heat transfer modeling and simulation between flue gases and sugar cane juice. • Use of Computational Fluid Dynamics to get thermal parameters of a jaggery furnace. • Data acquisition system installed in the jaggery production module. • Parametric analysis changing the flue-gases velocity to represent temperature drops. - Abstract: Jaggery (also called organic sugar) is a concentrated product of sugarcane juice that is produced in rural communities in the highlands and jungle of Peru. In the last few years there has been an increase in the exports of jaggery and higher volumes of production are required driving this activity from a rural process with small production to an industry seeking greater productivity. In this framework, optimization of the use of energy becomes essential for the proper development of the process of production and the correct performance of the involved equipment. Open heat exchangers made of stainless steel are used in the production of jaggery. These heat exchangers containing sugarcane juice are placed over a flue gas duct. The thermal energy contained in the gas is used to evaporate the water contained in the sugarcane juice thickening the juice and after evaporating almost all the water, a pasty crystalline yellow substance is left in the boiling pan which becomes solid after cooling, this is the jaggery. The modeling and simulation of heat transfer between the combustion gases and the juice is very important in order to improve the thermal efficiency of the process. It permits to know with a high level of detail the physical phenomena of heat transfer occurring from bagasse combustion flue gases to sugarcane juice. This paper presents the results of the numerical simulation of heat transfer phenomena in the open heat exchangers and those results are compared to field measured data. Numerical results about temperature drop of flue gases in the several locations of the jaggery furnace are in good accordance with

Valorization of the energy potential of fossil and fissile fuels for heat production: dual-purpose power plants and heat-producing nuclear reactors

International Nuclear Information System (INIS)

Lavite, Michel.

1975-07-01

The heat market is analyzed briefly within the French context: present structures and characteristics of the market, current means of heat production, predictable trend of the demand. The possible applications of nuclear energy to heat production, through the agency of combined electricity-steam stations or heat-producing stations, are then examined. Nuclear solutions are compared with others from the technico-economic and ecological wiewpoints and an estimate fo their respective impacts on the energy balance is attempted [fr

Production and Distribution Planning in District Heating Systems; Produktions- och distributionsplanering av fjaerrvaerme

Energy Technology Data Exchange (ETDEWEB)

Kvarnstroem, Johan; Dotzauer, Erik; Dahlquist, Erik

2006-12-15

To produce heat and power is costly. Therefore it is important for the district heating companies to plan and optimize the production. The aim with the present project is to find out how also the distribution of heat can be considered in the planning. The principal procedure is to first construct a prediction of the heat demand, and then, given the demand prediction, construct the production plan. Due to the complexity of the problem, the need for mathematical models is obvious. The report gives a survey introduction to production planning in district heating systems and presents a model for the purpose. The model is developed for one of the district heating systems in Stockholm owned by the energy company Fortum. Traditionally, models for production planning do not consider the distribution network. In such models, usually the methodology Mixed Integer Programming (MIP) is used. The report suggests how the distribution network can be modeled as a MIP; it shall be possible to link the network model to existing software that models the production plants as MIP. The model is developed in the programming language GAMS. Analysis and results are presented. The results show that the suggested plans vary depending on if the distribution network is considered or not. The report also suggests how a simple sensitivity analysis of the production plans can be performed. This is necessary since there are always uncertainties associated with weather- and load predictions.

An effective heuristic for combined heat-and-power production planning with power ramp constraints

International Nuclear Information System (INIS)

Rong, Aiying; Lahdelma, Risto

2007-01-01

Combined heat-and-power (CHP) production is an increasingly important technology for its efficient utilization of primary-energy resources and for reducing CO 2 emissions. In the CHP plant, the generation of heat-and-power follows a joint characteristic, which makes the determination of both the marginal power production cost (MPPC) and the feasible operating region for the plant more complicated than for the power-only generation plant. Due to the interdependence between heat and power production, the power-ramp constraints, which limit how much the power production of a CHP plant may increase or decrease between two successive periods, may also imply constraints on the heat production. In this paper, we investigate the impact of power-ramp constraints on CHP production planning and develop a robust heuristic for dealing with the power-ramp constraints based on the solution to the problem with relaxed ramp-constraints (RRC). Numerical results based on realistic production models show that the heuristic can generate high-quality solutions efficiently. (author)

A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production

Science.gov (United States)

Burton-Johnson, A.; Halpin, J.; Whittaker, J. M.; Graham, F. S.; Watson, S. J.

2017-12-01

We present recently published findings (Burton-Johnson et al., 2017) on the variability of Antarctic sub-glacial heat flux and the impact from upper crustal geology. Our new method reveals that the upper crust contributes up to 70% of the Antarctic Peninsula's subglacial heat flux, and that heat flux values are more variable at smaller spatial resolutions than geophysical methods can resolve. Results indicate a higher heat flux on the east and south of the Peninsula (mean 81 mWm-2) where silicic rocks predominate, than on the west and north (mean 67 mWm-2) where volcanic arc and quartzose sediments are dominant. Whilst the data supports the contribution of HPE-enriched granitic rocks to high heat flux values, sedimentary rocks can be of comparative importance dependent on their provenance and petrography. Models of subglacial heat flux must utilize a heterogeneous upper crust with variable radioactive heat production if they are to accurately predict basal conditions of the ice sheet. Our new methodology and dataset facilitate improved numerical model simulations of ice sheet dynamics. The most significant challenge faced remains accurate determination of crustal structure, particularly the depths of the HPE-enriched sedimentary basins and the sub-glacial geology away from exposed outcrops. Continuing research (particularly detailed geophysical interpretation) will better constrain these unknowns and the effect of upper crustal geology on the Antarctic ice sheet. Burton-Johnson, A., Halpin, J.A., Whittaker, J.M., Graham, F.S., and Watson, S.J., 2017, A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production: Geophysical Research Letters, v. 44, doi: 10.1002/2017GL073596.

Life Cycle Assessment of Miscanthus as a Fuel Alternative in District Heat Production

DEFF Research Database (Denmark)

Parajuli, Ranjan; Dalgaard, Tommy; Nguyen, T Lan T

2013-01-01

) plant. Alternatively, we have simulated the combustion process of Miscanthus in a boiler, where only heat is produced. For NG similar scenarios are examined. Life Cycle Assessment (LCA) in relation to 1 MJ of heat production with Miscanthus fired in a CHP would lead to a Global Warming Potential (GWP......This study assesses the environmental performance of district heat production based on Miscanthus as a fuel input and compares it with Natural Gas (NG). As a baseline scenario, we assume that the process of energy conversion from Miscanthus to heat takes place in a Combined Heat and Power (CHP......) of -0.071 kg CO2-eq, a Non-Renewable Energy (NRE) use of -0.767 MJ primary, and 0.09 m2 Land Use (LU). In contrast, production of 1 MJ of heat with Miscanthus fired in a boiler would lead to a GWP of 0.005 kg CO2-eq, NRE use 0.172 MJ primary, and land use 0.063 m2-a. Miscanthus fired in a CHP performs...

Technologies for production of electrticity or heat

International Nuclear Information System (INIS)

Schleisner, L.

1990-03-01

In connection with the production of ''Energi 2000 - Handlingsplan for en baeredygtig udvikling'' (Energy 2000 - Plan of Management for a Sustaniable Development) a summary and evaluation of various electric power and heat production technolgies was produced. Technologies in relation to fusion, wind energy, solar energy, wave energy, heat storage, electric power storage and hydrogen are dealt with. In each case a description of the technological development in the relevant field, also in relation to long (2030), middle (2015) and short term (2000) commercial aspects, is given. The technology is also explained in relation to energy and socio-economical aspects. The consequences of the utilization of the mentioned technologies with regard to the total energy and electric power systems and aspects of Danish industrial policy are considered. Suggestions are presented as to future subjects for research and development in relation to each technology. A number of these technologies are not yet used commercially. The descriptions are thus given on the basis of development on a global basis. (author) 32 tabs., 31 ills., 19 refs

On-line tritium production and heat deposition rate measurements at the Lotus facility

International Nuclear Information System (INIS)

Joneja, O.P.; Scherrer, P.; Anand, R.P.

1994-01-01

Integral tritium production and heat deposition measurement in a prototype fusion blanket would enable verification of the computational codes and the data based employed for the calculations. A large number of tritium production rate measurements have been reported for different type of blankets, whereas the direct heat deposition due to the mixed radiation field in the fusion environment, is still in its infancy. In order to ascertain the kerma factors and the photon production libraries, suitable techniques must be developed to directly measure the nuclear heat deposition rates in the materials required for the fusion systems. In this context, at the Lotus facility, we have developed an extremely efficient double ionizing chamber, for the on-line tritium production measurements and employed a pure graphite calorimeter to measure the nuclear heat deposition due to the mixed radiation field of the 14 MeV, Haefely neutron generator. This paper presents both systems and some of the recent measurements. (authors). 8 refs., 13 figs

Forecast of power generation and heat production from renewable energy sources

Directory of Open Access Journals (Sweden)

Pydych Tadeusz

2017-01-01

Full Text Available The share of renewable energy sources (RES in the end use of energy in the UE will increase from the present level of about 25% to 50 % in 2030 according to the assumptions of the European Commission. In Poland the RES Act was passed in 2015. The act defines mechanisms and instruments for supporting the production of electricity and heat from renewable energy sources. Statistics (2003–2014 of electricity generation and heat production from RES in Poland were used in the research. Because of amendments to regulations connected with promoting RES and the emissions trading system (ETS as well as the uncertainty associated with further directions of the energy and environmental policy, generation of electricity and heat based on the use of RES must be modelled while taking risk into account. A number of dynamic processes incorporating random events may be modelled by stochastic equations using Ito calculus. By applying Euler’s method to solve stochastic differential equations (SDE, it is possible to simulate the development of the use of renewable energy carriers in electricity generation and heat production in the future.

Heat resistance of Salmonella in various egg products.

Science.gov (United States)

Garibaldi, J A; Straka, R P; Ijichi, K

1969-04-01

The heat-resistance characteristics of Salmonella typhimurium Tm-1, a reference strain in the stationary phase of growth, were determined at several temperatures in the major types of products produced by the egg industry. The time required to kill 90% of the population (D value) at a given temperature in specific egg products was as follows: at 60 C (140 F), D = 0.27 min for whole egg; D = 0.60 min for whole egg plus 10% sucrose; D = 1.0 min for fortified whole egg; D = 0.20 min for egg white (pH 7.3), stabilized with aluminum; D = 0.40 min for egg yolk; D = 4.0 min for egg yolk plus 10% sucrose; D = 5.1 min for egg yolk plus 10% NaCl; D = 1.0 min for scrambled egg mix; at 55 C (131 F), D = 0.55 min for egg white (pH 9.2); D = 1.2 min for egg white (pH 9.2) plus 10% sucrose. The average Z value (number of degrees, either centigrade or fahrenheit, for a thermal destruction time curve to traverse one logarithmic cycle) was 4.6 C (8.3 F) with a range from 4.2 to 5.3 C. Supplementation with 10% sucrose appeared to have a severalfold greater effect on the heat stabilization of egg white proteins than on S. typhimurium Tm-1. This information should be of value in the formulation of heat treatments to insure that all egg products be free of viable salmonellae.

AGPase: its role in crop productivity with emphasis on heat tolerance in cereals.

Science.gov (United States)

Saripalli, Gautam; Gupta, Pushpendra Kumar

2015-10-01

AGPase, a key enzyme of starch biosynthetic pathway, has a significant role in crop productivity. Thermotolerant variants of AGPase in cereals may be used for developing cultivars, which may enhance productivity under heat stress. Improvement of crop productivity has always been the major goal of plant breeders to meet the global demand for food. However, crop productivity itself is influenced in a large measure by a number of abiotic stresses including heat, which causes major losses in crop productivity. In cereals, crop productivity in terms of grain yield mainly depends upon the seed starch content so that starch biosynthesis and the enzymes involved in this process have been a major area of investigation for plant physiologists and plant breeders alike. Considerable work has been done on AGPase and its role in crop productivity, particularly under heat stress, because this enzyme is one of the major enzymes, which catalyses the rate-limiting first committed key enzymatic step of starch biosynthesis. Keeping the above in view, this review focuses on the basic features of AGPase including its structure, regulatory mechanisms involving allosteric regulators, its sub-cellular localization and its genetics. Major emphasis, however, has been laid on the genetics of AGPases and its manipulation for developing high yielding cultivars that will have comparable productivity under heat stress. Some important thermotolerant variants of AGPase, which mainly involve specific amino acid substitutions, have been highlighted, and the prospects of using these thermotolerant variants of AGPase in developing cultivars for heat prone areas have been discussed. The review also includes a brief account on transgenics for AGPase, which have been developed for basic studies and crop improvement.

Computer simulation for improving radio frequency (RF) heating uniformity of food products: A review.

Science.gov (United States)

Huang, Zhi; Marra, Francesco; Subbiah, Jeyamkondan; Wang, Shaojin

2018-04-13

Radio frequency (RF) heating has great potential for achieving rapid and volumetric heating in foods, providing safe and high-quality food products due to deep penetration depth, moisture self-balance effects, and leaving no chemical residues. However, the nonuniform heating problem (usually resulting in hot and cold spots in the heated product) needs to be resolved. The inhomogeneous temperature distribution not only affects the quality of the food but also raises the issue of food safety when the microorganisms or insects may not be controlled in the cold spots. The mathematical modeling for RF heating processes has been extensively studied in a wide variety of agricultural products recently. This paper presents a comprehensive review of recent progresses in computer simulation for RF heating uniformity improvement and the offered solutions to reduce the heating nonuniformity. It provides a brief introduction on the basic principle of RF heating technology, analyzes the applications of numerical simulation, and discusses the factors influencing the RF heating uniformity and the possible methods to improve heating uniformity. Mathematical modeling improves the understanding of RF heating of food and is essential to optimize the RF treatment protocol for pasteurization and disinfestation applications. Recommendations for future research have been proposed to further improve the accuracy of numerical models, by covering both heat and mass transfers in the model, validating these models with sample movement and mixing, and identifying the important model parameters by sensitivity analysis.

3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt.

Science.gov (United States)

Al-Alfy, I M; Nabih, M A

2013-03-01

A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 μWm(-3) to 2.2 μWm(-3). Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 μWm(-3) is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

International Nuclear Information System (INIS)

Lythcke-Jørgensen, Christoffer; Haglind, Fredrik; Clausen, Lasse R.

2014-01-01

Highlights: • We model a system where lignocellulosic ethanol production is integrated with a combined heat and power (CHP) plant. • We conduct an exergy analysis for the ethanol production in six different system operation points. • Integrated operation, district heating (DH) production and low CHP loads all increase the exergy efficiency. • Separate operation has the largest negative impact on the exergy efficiency. • Operation is found to have a significant impact on the exergy efficiency of the ethanol production. - Abstract: Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible, and a gas boiler is used as back-up when integration is not possible. The system was evaluated according to six operation points that alternate on the following three different operation parameters: Load in the CHP unit, integrated versus separate operation, and inclusion of district heating production in the ethanol facility. The calculated standard exergy efficiency of the ethanol facility varied from 0.564 to 0.855, of which the highest was obtained for integrated operation at reduced CHP load and full district heating production in the ethanol facility, and the lowest for separate operation with zero district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the

Local Entropy Production in Turbulent Shear Flows: A Tool for Evaluating Heat Transfer Performance

Institute of Scientific and Technical Information of China (English)

H. HERWIG; F. KOCK

2006-01-01

Performance evaluation of heat transfer devices can be based on the overall entropy production in these devices.In our study we therefore provide equations for the systematic and detailed determination of local entropy production due to dissipation of mechanical energy and due to heat conduction, both in turbulent flows. After turbulence modeling has been incorporated for the fluctuating parts the overall entropy production can be determined by integration with respect to the whole flow domain. Since, however, entropy production rates show very steep gradients close to the wall, numerical solutions are far more effective with wall functions for the entropy production terms. These wall functions are mandatory when high Reynolds number turbulence models are used. For turbulent flow in a pipe with an inserted twisted tape as heat transfer promoter it is shown that based on the overall entropy production rate a clear statement from a thermodynamic point of view is possible. For a certain range of twist strength there is a decrease in overall entropy production compared to the case without insert. Also, the optimum twist strength can be determined. This information is unavailable when only pressure drop and heat transfer data are given.

Removal of corrosion products of construction materials in heat carrier

International Nuclear Information System (INIS)

1975-01-01

A review of reported data has been made on the removal of structural material corrosion products into the heat-carrying agent of power reactors. The corrosion rate, and at the same time, removal of corrosion products into the heat-carrying agent (water) decreases with time. Thus, for example, the corrosion rate of carbon steel in boiling water at 250 deg C and O 2 concentration of 0.1 mg/1 after 3000 hr is 0.083 g/m 2 . day; after 9000 hr the corrosion rate has been reduced 2.5 times. Under static conditions the transfer rate of corrosion products into water has been smaller than in the stream and also depends on time. The corrosion rate of carbon steel under nuclear plant operating conditions is almost an order higher over that of steel Kh18N10T

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

DEFF Research Database (Denmark)

Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

2013-01-01

produces ethanol, solid biofuel, molasses, and is able to produce district heating hot water. Considering all products equally valuable, the exergy efficiency of the ethanol facility was found to be 0.790 during integrated operation with zero district heating production, and 0.852 during integrated...

Reverse electrodialysis heat engine for sustainable power production

International Nuclear Information System (INIS)

Tamburini, A.; Tedesco, M.; Cipollina, A.; Micale, G.; Ciofalo, M.; Papapetrou, M.; Van Baak, W.; Piacentino, A.

2017-01-01

Graphical abstract: State of the art technologies for the conversion of heat into power. Grey circles refer to technologies at very early stage of development and non-available at industrial level. The Carnot efficiency (on the secondary horizontal axis) is evaluated assuming a cold sink temperature of 25 °C. SRC-hot gases: Steam Rankine Cycle integrated with gas turbine/other topping cycles; SRC-fuel: Steam Rankine Cycle directly fuelled by oil, coal or other fuels; KC: Kalina Cycle; ORC: Organic Rankine Cycle; TEG: Thermoelectric Generation; PEPG: Piezoelectric Power Generation with waste heat-powered expansion/compression cycle; OHE: Osmotic Heat Engine; REDHE, Reverse Electrodialysis Heat Engine (this paper). Display Omitted -- Highlights: •For the first time, the potential of Reverse Electrodialysis Heat Engine is assessed. •An overview of the possible regeneration methods is presented. •Performance of the RED unit fed by different salty solutions was suitably optimized. •Three different RED Heat Engine scenarios were studied. •Exergetic efficiency of about 85% could be achieved in the foreseen future. -- Abstract: Reverse Electrodialysis Heat Engine (REDHE) is a promising technology to convert waste heat at temperatures lower than 100 °C into electric power. In the present work an overview of the possible regeneration methods is presented and the technological challenges for the development of the RED Heat Engine (REDHE) are identified. The potential of this power production cycle was investigated through a simplified mathematical model. In the first part of the work, several salts were singularly modelled as possible solutes in aqueous solutions feeding the RED unit and the corresponding optimal conditions were recognized via an optimization study. In the second part, three different RED Heat Engine scenarios were studied. Results show that power densities much higher than those relevant to NaCl-water solutions can be obtained by using different

Biogas production supported by excess heat – A systems analysis within the food industry

International Nuclear Information System (INIS)

Broberg Viklund, Sarah; Lindkvist, Emma

2015-01-01

Highlights: • A systems analysis when moving from external to internal production and use of biogas at an industry. • The aim is to study the impacts on greenhouse gas emissions and economics from this switch. • The study compares the choice of using biogas or industrial excess heat to heat the digester. • Internal biogas production supported by excess heat has environmental and economic benefits. - Abstract: The aim of this paper was to study the effects on greenhouse gases and economics when a change is made in the use of industrial organic waste from external production and use of biogas (A) to internal production and use (B). The two different system solutions are studied through a systems analysis based on an industrial case. The baseline system (A) and a modified system (B) were compared and analysed. Studies show that industrial processes considered as integrated systems, including the exchange of resources between industries, can result in competitive advantages. This study focuses on the integration of internally produced biogas from food industry waste produced by a food company and the use of excess heat. Two alternative scenarios were studied: (1) the use of available excess heat to heat the biogas digester and (2) the use of a part of the biogas produced to heat the biogas digester. This study showed that the system solution, whereby excess heat rather than biogas is used to heat the biogas digester, was both environmentally and economically advantageous. However, the valuation of biomass affects the magnitude of the emissions reduction. Implementing this synergistic concept will contribute to the reaching of European Union climate targets

Heat integration in processes with diverse production lines: A comprehensive framework and an application in food industry

International Nuclear Information System (INIS)

Miah, J.H.; Griffiths, A.; McNeill, R.; Poonaji, I.; Martin, R.; Yang, A.; Morse, S.

2014-01-01

Highlights: • A new practical heat integration framework was developed for complex and diverse production lines. • Heat recovery was maximised by direct and indirect heat integration at zonal and factory levels. • A novel approach to stream data extraction was proposed to account for both stream capacity and availability. • A case study was carried out on a multi-product confectionery factory. - Abstract: Heat integration is a key measure to improving energy efficiency and maximising heat recovery. Since the advent of Pinch analysis in the 1980s, direct and indirect integration approaches have developed in separate domains with very few examples where both approaches are utilised together to maximise heat recovery. This paper presents a novel decision-making framework for heat integration in complex and diverse production lines, with the aim to provide the user with a step-by-step guide to evaluate all heat recovery opportunities through a combination of direct and indirect heat integration. This framework involves analysis at both the zonal level and the factory level. The proposed framework was applied to a case study based on a confectionery factory in the UK that manufactured multiple products across a diverse range of food technologies. It demonstrates that the framework can effectively identify the significant streams to be considered in the heat integration analysis, and address practical factors such as diverse production times, geographical proximity, and potential of compromise to product quality when the direct and indirect heat integration opportunities are proposed and assessed both within and between production zones. This practical framework has the potential to benefit the wider food industry and beyond

Metabolic heat production by human and animal populations in cities

Science.gov (United States)

Stewart, Iain D.; Kennedy, Chris A.

2017-07-01

Anthropogenic heating from building energy use, vehicle fuel consumption, and human metabolism is a key term in the urban energy budget equation. Heating from human metabolism, however, is often excluded from urban energy budgets because it is widely observed to be negligible. Few reports for low-latitude cities are available to support this observation, and no reports exist on the contribution of domestic animals to urban heat budgets. To provide a more comprehensive view of metabolic heating in cities, we quantified all terms of the anthropogenic heat budget at metropolitan scale for the world's 26 largest cities, using a top-down statistical approach. Results show that metabolic heat release from human populations in mid-latitude cities (e.g. London, Tokyo, New York) accounts for 4-8% of annual anthropogenic heating, compared to 10-45% in high-density tropical cities (e.g. Cairo, Dhaka, Kolkata). Heat release from animal populations amounts to <1% of anthropogenic heating in all cities. Heat flux density from human and animal metabolism combined is highest in Mumbai—the world's most densely populated megacity—at 6.5 W m-2, surpassing heat production by electricity use in buildings (5.8 W m-2) and fuel combustion in vehicles (3.9 W m-2). These findings, along with recent output from global climate models, suggest that in the world's largest and most crowded cities, heat emissions from human metabolism alone can force measurable change in mean annual temperature at regional scale.

Metabolic heat production by human and animal populations in cities.

Science.gov (United States)

Stewart, Iain D; Kennedy, Chris A

2017-07-01

Anthropogenic heating from building energy use, vehicle fuel consumption, and human metabolism is a key term in the urban energy budget equation. Heating from human metabolism, however, is often excluded from urban energy budgets because it is widely observed to be negligible. Few reports for low-latitude cities are available to support this observation, and no reports exist on the contribution of domestic animals to urban heat budgets. To provide a more comprehensive view of metabolic heating in cities, we quantified all terms of the anthropogenic heat budget at metropolitan scale for the world's 26 largest cities, using a top-down statistical approach. Results show that metabolic heat release from human populations in mid-latitude cities (e.g. London, Tokyo, New York) accounts for 4-8% of annual anthropogenic heating, compared to 10-45% in high-density tropical cities (e.g. Cairo, Dhaka, Kolkata). Heat release from animal populations amounts to heating in all cities. Heat flux density from human and animal metabolism combined is highest in Mumbai-the world's most densely populated megacity-at 6.5 W m -2 , surpassing heat production by electricity use in buildings (5.8 W m -2 ) and fuel combustion in vehicles (3.9 W m -2 ). These findings, along with recent output from global climate models, suggest that in the world's largest and most crowded cities, heat emissions from human metabolism alone can force measurable change in mean annual temperature at regional scale.

Production of dry wood chips in connection with a district heating plant

Directory of Open Access Journals (Sweden)

Yrjölä Jukka

2004-01-01

Full Text Available Moisture and its variation in wood chips make the control of burning in small scale heating appliances difficult resulting in emissions and loss of efficiency. If the quality of wood chips would be better, i. e. dried and sieved fuel with more uniform size distribution would be avail able, the burning could be much cleaner and efficiency higher. In addition higher power out put could be obtained and the investment costs of the burning appliances would be lower. The production of sieved and dried wood chip with good quality could be accomplished in connection with a district heating plant. Then the plant would make profit, in addition to the district heat, from the dried wood chips sold to the neighboring buildings and enterprises sep a rated from the district heating net using wood chips in energy production. The peak power of a district heating plant is required only a short time during the coldest days of the winter. Then the excess capacity during the milder days can be used as heat source for drying of wood chips to be marketed. Then wood chips are sieved and the fuel with best quality is sold and the reject is used as fuel in the plant it self. In a larger district heating plant, quality of the fuel does not need to be so high In this paper the effect of moisture on the fuel chain and on the boiler is discussed. Energy and mass balance calculations as a tool of system design is described and the characteristics of proposed dry chips production method is discussed.

Development of shelf stable, processed, low acid food products using heat-irradiation combination treatments

International Nuclear Information System (INIS)

Minnaar, A.

1998-01-01

The amount of ionizing irradiation needed to sterilize low acid vegetable and starch products (with and without sauces) commercially impairs their sensorial and nutritive qualities, and use of thermal processes for the same purpose may also have an adverse effect on the product quality. A systematic approach to the establishment of optimized combination parameters was developed for heat-irradiation processing to produce high quality, shelf stable, low acid food products. The effects of selected heat, heat-irradiation combination and irradiation treatments on the quality of shelf stable mushrooms in brine and rice, stored at ambient temperature, were studied. From a quality viewpoint, use of heat-irradiation combination treatments favouring low irradiation dose levels offered a feasible alternative to thermally processed or radappertized mushrooms in brine. However, shelf stable rice produced by heat-irradiation combination treatments offered a feasible alternative only to radappertized rice from the standpoint of quality. The technical requirements for the heat and irradiation processing of a long grain rice cultivar from the United States of America oppose each other directly, thereby reducing the feasibility of using heat-irradiation combination processing to produce shelf stable rice. The stability of starch thickened white sauces was found to be affected severely during high dose irradiation and subsequent storage at ambient temperature. However, use of pea protein isolate as a thickener in white sauces was found to have the potential to maintain the viscosity of sauces for irradiated meat and sauce products throughout processing and storage. (author)

An application program for fission product decay heat calculations

International Nuclear Information System (INIS)

Pham, Ngoc Son; Katakura, Jun-ichi

2007-10-01

The precise knowledge of decay heat is one of the most important factors in safety design and operation of nuclear power facilities. Furthermore, decay heat data also play an important role in design of fuel discharges, fuel storage and transport flasks, and in spent fuel management and processing. In this study, a new application program, called DHP (Decay Heat Power program), has been developed for exact decay heat summation calculations, uncertainty analysis, and for determination of the individual contribution of each fission product. The analytical methods were applied in the program without any simplification or approximation, in which all of linear and non-linear decay chains, and 12 decay modes, including ground state and meta-stable states, are automatically identified, and processed by using a decay data library and a fission yield data file, both in ENDF/B-VI format. The window interface of the program is designed with optional properties which is very easy for users to run the code. (author)

3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt

International Nuclear Information System (INIS)

Al-Alfy, I.M.; Nabih, M.A.

2013-01-01

A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 μWm −3 to 2.2 μWm −3 . Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 μWm −3 is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. - Highlights: ► Radiogenic heat production ranging from 0.21 to 2.25 μWm −3 averaging about 0.95 μWm −3 . ► High Stdev. 0.3 μWm −3 indicates a heterogenic distribution of (RHP) values. ► Statistically, the range from 0.8 to 1.2 μWm −3 is about 45.3 % of the values. ► A renew RHP which can be produced from the study area are calculated as 6.3 kW

Design for manufacturability of macro and micro products: a case study of heat exchanger design

DEFF Research Database (Denmark)

Omidvarnia, F.; Weng Feng, L.; Hansen, H. N.

2018-01-01

In this paper, a novel methodology in designing a micro heat exchanger is proposed by modifying a conventional design methodology for macro products with the considerations of differences between design of a micro and a macro product. The methodology starts with the identification of differences...... for fabricating micro heat exchangers are ranked based on the defined criteria. Following the design methodology, primary design ideas for micro heat exchangers are generated according to the heat transfer principles for macro heat exchangers. Taking micro design considerations into account, the designs from next...... iteration are created. Finally, the performances of the designs for micro heat exchangers are compared with their macro counterparts. The most appropriate designs for micro heat exchangers are finalized. The micro specific design guidelines obtained by the designer through evaluating the modeling results...

Production of synthesis gas and methane via coal gasification utilizing nuclear heat

International Nuclear Information System (INIS)

van Heek, K.H.; Juentgen, H.

1982-01-01

The steam gasificaton of coal requires a large amount of energy for endothermic gasification, as well as for production and heating of the steam and for electricity generation. In hydrogasification processes, heat is required primarily for the production of hydrogen and for preheating the reactants. Current developments in nuclear energy enable a gas cooled high temperature nuclear reactor (HTR) to be the energy source, the heat produced being withdrawn from the system by means of a helium loop. There is a prospect of converting coal, in optimal yield, into a commercial gas by employing the process heat from a gas-cooled HTR. The advantages of this process are: (1) conservation of coal reserves via more efficient gas production; (2) because of this coal conservation, there are lower emissions, especially of CO 2 , but also of dust, SO 2 , NO/sub x/, and other harmful substances; (3) process engineering advantages, such as omission of an oxygen plant and reduction in the number of gas scrubbers; (4) lower gas manufacturing costs compared to conventional processes. The main problems involved in using nuclear energy for the industrial gasification of coal are: (1) development of HTRs with helium outlet temperatures of at least 950 0 C; (2) heat transfer from the core of the reactor to the gas generator, methane reforming oven, or heater for the hydrogenation gas; (3) development of a suitable allothermal gas generator for the steam gasification; and (4) development of a helium-heated methane reforming oven and adaption of the hydrogasification process for operation in combination with the reactor. In summary, processes for gasifying coal that employ heat from an HTR have good economic and technical prospects of being realized in the future. However, time will be required for research and development before industrial application can take place. 23 figures, 4 tables. (DP)

Catalytic heat exchangers for small-scale production of hydrogen - feasibility study

Energy Technology Data Exchange (ETDEWEB)

Silversand, F [Catator AB, Lund (Sweden)

2002-02-01

A feasibility study concerning heat-exchanger reactors in small-scale production of hydrogen has been performed on the request of Svenskt Gastekniskt Center AB and SWEP International AB. The basic idea is to implement different catalysts into brazed plate-type heat exchangers. This can be achieved by installing catalytic cylinders in the inlet-and outlet ports of the heat exchangers or through treatment of the plates to render them catalytically active. It is also possible to sandwich catalytically active wire meshes between the plates. Experiments concerning steam reforming of methanol and methane have been performed in a micro-reactor to gather kinetic data for modelling purposes. Performance calculations concerning heat exchanger reactors have then been conducted with Catator's generic simulation code for catalytic reactors (CatalystExplorer). The simulations clearly demonstrate the technical performance of these reactors. Indeed, the production rate of hydrogen is expected to be about 10 nm{sup 3}/h per litre of heat exchanger. The corresponding value for a conventional steam-reforming unit is about 1 nm{sup 3}/h or less per litre of reactor volume. Also, the compactness and the high degree of integration together with the possibilities of mass production will give an attractive cost for such units. Depending on the demands concerning the purity of the hydrogen it is possible to add secondary catalytic steps like water-gas shifters, methanation and selective oxidation, into a one-train unit, i.e. to design an all-inclusive design. Such reactors can be used for the supply of hydrogen to fuel cells. The production cost for hydrogen can be cut by 60 - 70% through the utilisation of heat exchanger reactors instead of conventional electrolysis. This result is primarily a result of the high price for electricity compared to the feed stock prices in steam reforming. It is important to verify the performance calculations and the simulation results through experimental

Catalytic heat exchangers for small-scale production of hydrogen - feasibility study

Energy Technology Data Exchange (ETDEWEB)

Silversand, F. [Catator AB, Lund (Sweden)

2002-02-01

A feasibility study concerning heat-exchanger reactors in small-scale production of hydrogen has been performed on the request of Svenskt Gastekniskt Center AB and SWEP International AB. The basic idea is to implement different catalysts into brazed plate-type heat exchangers. This can be achieved by installing catalytic cylinders in the inlet-and outlet ports of the heat exchangers or through treatment of the plates to render them catalytically active. It is also possible to sandwich catalytically active wire meshes between the plates. Experiments concerning steam reforming of methanol and methane have been performed in a micro-reactor to gather kinetic data for modelling purposes. Performance calculations concerning heat exchanger reactors have then been conducted with Catator's generic simulation code for catalytic reactors (CatalystExplorer). The simulations clearly demonstrate the technical performance of these reactors. Indeed, the production rate of hydrogen is expected to be about 10 nm{sup 3}/h per litre of heat exchanger. The corresponding value for a conventional steam-reforming unit is about 1 nm{sup 3}/h or less per litre of reactor volume. Also, the compactness and the high degree of integration together with the possibilities of mass production will give an attractive cost for such units. Depending on the demands concerning the purity of the hydrogen it is possible to add secondary catalytic steps like water-gas shifters, methanation and selective oxidation, into a one-train unit, i.e. to design an all-inclusive design. Such reactors can be used for the supply of hydrogen to fuel cells. The production cost for hydrogen can be cut by 60 - 70% through the utilisation of heat exchanger reactors instead of conventional electrolysis. This result is primarily a result of the high price for electricity compared to the feed stock prices in steam reforming. It is important to verify the performance calculations and the simulation results through

Some Problems of the Integration of Heat Pump Technology into a System of Combined Heat and Electricity Production

Directory of Open Access Journals (Sweden)

G. Böszörményi

2001-01-01

Full Text Available The closure of a part of the municipal combined heat and power (CHP plant of Košice city would result in the loss of 200 MW thermal output within a realtively short period of time. The long term development plan for the Košice district heating system concentrates on solving this problem. Taking into account the extremely high (90 % dependence of Slovakia on imported energy sources and the desirability of reducing the emission of pollutantst the alternative of supplying of 100 MW thermal output from geothermal sources is attractive. However the indices of economic efficiency for this alternative are unsatisfactory. Cogeneration of electricity and heat in a CHP plant, the most efficient way of supplying heat to Košice at the present time. If as planned, geothermal heat is fed directly into the district heating network the efficiency would be greatly reduced. An excellent solution of this problem would be a new conception, preferring the utilization of geothermal heat in support of a combined electricity and heat production process. The efficiency of geothermal energy utilization could be increased through a special heat pump. This paper deals with several aspects of the design of a heat pump to be integrated into the system of the CHP plant.

Application of industrial wood residues for combined heat and power production

International Nuclear Information System (INIS)

Majchrzycka, A.

2015-01-01

The paper discusses combined production of heat and power (CHP) from industrial wood residues. The system will be powered by wood residues generated during manufacturing process of wooden floor panels. Based on power and heat demands of the plant and wood residues potential, the CHP system was selected. Preliminary analysis of biomass conversion in CHP system and environmental impact was performed.

Thermal histories of convective earth models and constraints on radiogenic heat production in the earth

International Nuclear Information System (INIS)

Davies, G.F.

1980-01-01

Thermal histories have been calculated for simple models of the earth which assume that heat is transported by convection throughout the interior. The application of independent constraints to these solutions limits the acceptable range of the ratio of present radiogenic heat production in the earth to the present surface heat flux. The models use an empirical relation between the rate of convective heat transport and the temperature difference across a convecting fluid. This is combined with an approximate proportionality between effective mantle viscosity and T/sup -n/, where T is temperature and it is argued that n is about 30 throughout the mantle. The large value of n causes T to be strongly buffered against changes in the earth's energy budget and shortens by an order of magnitude the response time of surface heat flux to changes in energy budget as compared to less temperature-dependent heat transport mechanisms. Nevertheless, response times with n=30 are still as long as 1 or 2 b.y. Assuming that the present heat flux is entirely primordial (i.e., nonradiogenic) in a convective model leads back to unrealistically high temperatures about 1.7 b.y. ago. Inclusion of exponentially decaying (i.e., radiogenic) heat sources moves the high temperatures further into the past and leads to a transition from 'hot' to 'cool' calculated thermal histories for the case when the present rate of heat production is near 50% of the present rate of heat loss. Requiring the calculated histories to satisfy minimal geological constraints limits the present heat production/heat loss ratio to between about 0.3 and 0.85. Plausible stronger constraints narrow this range to between 0.45 and 0.65. These results are compatible with estimated radiogentic heat production rates in some meteorites and terrestrial rocks, with a whole-earth K/U ratio of 1--2 x 10 4 giving optimal agreement

Vertical integration of local fuel producers into rural district heating systems – Climate impact and production costs

International Nuclear Information System (INIS)

Kimming, M.; Sundberg, C.; Nordberg, Å.; Hansson, P.-A.

2015-01-01

Farmers can use their own agricultural biomass residues for heat production in small-scale systems, enabling synergies between the district heating (DH) sector and agriculture. The barriers to entry into the Swedish heat market were extremely high as long as heat distribution were considered natural monopoly, but were recently lowered due to the introduction of a regulated third party access (TPA) system in the DH sector. This study assesses the potential impact on greenhouse gas emissions and cost-based heat price in the DH sector when farmers vertically integrate into the heat supply chain and introduce more local and agricultural crops and residues into the fuel mix. Four scenarios with various degree of farmer integration, were assessed using life cycle assessment (LCA) methodology, and by analysis of the heat production costs. The results show that full integration of local farm and forest owners in the value chain can reduce greenhouse gas emissions and lower production costs/heat price, if there is an incentive to utilise local and agricultural fuels. The results imply that farmer participation in the DH sector should be encouraged by e.g. EU rural development programmes. - Highlights: • Five DH production systems based on different fuels and ownership were analysed. • Lower GHG emissions were obtained when farmers integrate fully into the DH chain. • Lower heat price was obtained by full vertical integration of farmers. • Salix and straw-based production resulted in the lowest GHG and heat price

Thermodynamic Analysis of a Ship Power Plant Operating with Waste Heat Recovery through Combined Heat and Power Production

Directory of Open Access Journals (Sweden)

Mirko Grljušić

2014-11-01

Full Text Available The goal of this research is to study a cogeneration plant for combined heat & power (CHP production that utilises the low-temperature waste energy in the power plant of a Suezmax-size oil tanker for all heating and electricity requirements during navigation. After considering various configurations, a standard propulsion engine operating at maximum efficiency and a CHP Plant with R245fa fluid using a supercritical organic Rankine cycle (ORC is selected. All the ship heat requirements can be covered by energy of organic fluid after expansion in the turbine, except feeder-booster heating. Hence, an additional quantity of working fluid may be heated using an after Heat Recovery Steam Generator (HRSG directed to the feeder-booster module. An analysis of the obtained results shows that the steam turbine plant does not yield significant fuel savings. However, a CHP plant with R245fa fluid using supercritical ORC meets all of the demands for electrical energy and heat while burning only a small amount of additional fuel in HRSG at the main engine off-design operation.

A Simulation Study of Inter Heat Exchanger Process in SI Cycle Process for Hydrogen Production

International Nuclear Information System (INIS)

Shin, Jae Sun; Cho, Sung Jin; Choi, Suk Hoon; Qasim, Faraz; Lee, Euy Soo; Park, Sang Jin; Lee, Heung N.; Park, Jae Ho; Lee, Won Jae

2014-01-01

SI Cyclic process is one of the thermochemical hydrogen production processes using iodine and sulfur for producing hydrogen molecules from water. VHTR (Very High Temperature Reactor) can be used to supply heat to hydrogen production process, which is a high temperature nuclear reactor. IHX (Intermediate Heat Exchanger) is necessary to transfer heat to hydrogen production process safely without radioactivity. In this study, the strategy for the optimum design of IHX between SI hydrogen process and VHTR is proposed for various operating pressures of the reactor, and the different cooling fluids. Most economical efficiency of IHX is also proposed along with process conditions

The heat insulating properties of potato starch extruded with addition of chosen by- products of food industry

Directory of Open Access Journals (Sweden)

Zdybel Ewa

2014-12-01

Full Text Available The study was aimed at determination of time of heat transition through the layer of quince, apple, linen, rose pomace and potato pulp, as well as layer of potato starch and potato starch extruded with addition of above mentioned by-products. Additionally the attempt of creation a heat insulating barrier from researched raw material was made. The heat conductivity of researched materials was dependent on the type of material and its humidity. Extruded potato starch is characterized by smaller heat conductivity than potato starch extruded with addition of pomace. The obtained rigid extruded starch moulders were characterized by higher heat insulating properties than the loose beads. It is possible to use starch and by-products of food industry for production of heat insulating materials.

Comparing costs of power and heat production by prospective and present sources

International Nuclear Information System (INIS)

Novak, S.

1979-01-01

Capital and running costs are compared of power and heat production from different sources. The lowest capital costs were found for coal-fired power plants followed by light water reactor power plants. The capital costs of other types of power plants, such as wind, geothermal, solar, thermonuclear power plants are significantly higher. The estimated specific cost for electric power production in 1985 for a nuclear power plant is lower than for a fossil-fuel power plant. It is estimated that in 1985 coal will be the cheapest heat source. (Ha)

Model for optimization of plant investments in combined power and heat production systems

Energy Technology Data Exchange (ETDEWEB)

Jantunen, E.; Sinisalo, A.; Koskelainen, L.

1980-01-01

A mathematical model is developed for optimal dimensioning and timing the investments of power and heat production system in a community. The required electric power may be purchased by different production systems, such as: thermal power plants, gas turbines, diesel plants, etc. or by delivering all or part of it from a national power company. Also the required heat may be produced in many different ways in single-purpose or combined plants. The model assumes the extent of the heating system fixed, and it is not optimized. It is assumed that the same company is responsible for supplying both the power and heat for the community. It's aim is to allocate the existing capital in an optimal way, and the model may be used for facilitating the decision in such questions as: what kind of production capacity should be purchased in future; how high should the heat and power capacities be; and when should this additional capacity be available. The report also reviews the methods for forecasting the demand of power and heat and their fluctuation during the planning period. The solution of this large-scale non-linear optimization problem is searched via successive linearizations by using the Method of Approximate Programming (MAP). It was found that the solution method is very suitable for this kind of multivariable problems. The computing times with the Functional Mathematical Programmin System (FMPS) in Univac 1108 computer were quite reasonable.

Educational gradients in the use of electronic cigarettes and heat-not-burn tobacco products in Japan.

Science.gov (United States)

Miyazaki, Yuki; Tabuchi, Takahiro

2018-01-01

In addition to electronic cigarettes (e-cigarettes), tobacco companies have recently begun to sell heat-not-burn tobacco products, Ploom and iQOS in Japan. Previous research has reported an inverse association between combustible cigarette smoking and educational attainment, but little is known about the association for e-cigarettes, especially heat-not-burn tobacco products. Our objective was to analyze the relationship between educational attainment and e-cigarette and heat-not-burn tobacco use. An internet survey (randomly sampled research agency panelists) in Japan. A total of 7338 respondents aged 18-69 years in 2015 (3632 men and 3706women). Adjusted odds ratios (ORs) of educational attainment for current smoking (combustible cigarettes), e-cigarette ever-use, and heat-not-burn ever-use were calculated by multivariable logistic regression models using covariates including socio-demographic factors. Stratified analyses according to smoking status (combustible cigarettes) were additionally performed for e-cigarette ever-use and heat-not-burn tobacco product ever-use. Associations between educational attainment and e-cigarette ever-use or heat-not-burn tobacco ever-use are not straightforward, although these associations are not statistically significant except for one cell. For example, using "graduate school" education as a reference category, adjusted ORs for "high school" were 1.44 (95% confidence interval [CI]: 0.85-2.44) for e-cigarettes ever-use and 0.75 (95% CI:0.19-2.97) for heat-not-burn tobacco product ever-use. Among current smokers, compared with "graduate school" (reference), those with lower educational attainment showed 0.6 to 0.7 ORs for e-cigarette ever-use: e.g.,"4-year university"(OR = 0.54, 95% CI:0.24-1.24) and "high school" (OR = 0.69, 95% CI: 0.30-1.60). Among former smokers, lower education indicated higher ORs for both e-cigarettes and heat-not-burn tobacco ever-use. This study provides baseline information on educational gradients of e

Educational gradients in the use of electronic cigarettes and heat-not-burn tobacco products in Japan.

Directory of Open Access Journals (Sweden)

Yuki Miyazaki

Full Text Available In addition to electronic cigarettes (e-cigarettes, tobacco companies have recently begun to sell heat-not-burn tobacco products, Ploom and iQOS in Japan. Previous research has reported an inverse association between combustible cigarette smoking and educational attainment, but little is known about the association for e-cigarettes, especially heat-not-burn tobacco products. Our objective was to analyze the relationship between educational attainment and e-cigarette and heat-not-burn tobacco use.An internet survey (randomly sampled research agency panelists in Japan.A total of 7338 respondents aged 18-69 years in 2015 (3632 men and 3706women.Adjusted odds ratios (ORs of educational attainment for current smoking (combustible cigarettes, e-cigarette ever-use, and heat-not-burn ever-use were calculated by multivariable logistic regression models using covariates including socio-demographic factors. Stratified analyses according to smoking status (combustible cigarettes were additionally performed for e-cigarette ever-use and heat-not-burn tobacco product ever-use.Associations between educational attainment and e-cigarette ever-use or heat-not-burn tobacco ever-use are not straightforward, although these associations are not statistically significant except for one cell. For example, using "graduate school" education as a reference category, adjusted ORs for "high school" were 1.44 (95% confidence interval [CI]: 0.85-2.44 for e-cigarettes ever-use and 0.75 (95% CI:0.19-2.97 for heat-not-burn tobacco product ever-use. Among current smokers, compared with "graduate school" (reference, those with lower educational attainment showed 0.6 to 0.7 ORs for e-cigarette ever-use: e.g.,"4-year university"(OR = 0.54, 95% CI:0.24-1.24 and "high school" (OR = 0.69, 95% CI: 0.30-1.60. Among former smokers, lower education indicated higher ORs for both e-cigarettes and heat-not-burn tobacco ever-use.This study provides baseline information on educational gradients

Educational gradients in the use of electronic cigarettes and heat-not-burn tobacco products in Japan

Science.gov (United States)

Miyazaki, Yuki

2018-01-01

Objectives In addition to electronic cigarettes (e-cigarettes), tobacco companies have recently begun to sell heat-not-burn tobacco products, Ploom and iQOS in Japan. Previous research has reported an inverse association between combustible cigarette smoking and educational attainment, but little is known about the association for e-cigarettes, especially heat-not-burn tobacco products. Our objective was to analyze the relationship between educational attainment and e-cigarette and heat-not-burn tobacco use. Setting An internet survey (randomly sampled research agency panelists) in Japan. Participants A total of 7338 respondents aged 18–69 years in 2015 (3632 men and 3706women). Primary measures Adjusted odds ratios (ORs) of educational attainment for current smoking (combustible cigarettes), e-cigarette ever-use, and heat-not-burn ever-use were calculated by multivariable logistic regression models using covariates including socio-demographic factors. Stratified analyses according to smoking status (combustible cigarettes) were additionally performed for e-cigarette ever-use and heat-not-burn tobacco product ever-use. Results Associations between educational attainment and e-cigarette ever-use or heat-not-burn tobacco ever-use are not straightforward, although these associations are not statistically significant except for one cell. For example, using "graduate school" education as a reference category, adjusted ORs for "high school" were 1.44 (95% confidence interval [CI]: 0.85–2.44) for e-cigarettes ever-use and 0.75 (95% CI:0.19–2.97) for heat-not-burn tobacco product ever-use. Among current smokers, compared with “graduate school” (reference), those with lower educational attainment showed 0.6 to 0.7 ORs for e-cigarette ever-use: e.g.,"4-year university"(OR = 0.54, 95% CI:0.24–1.24) and "high school" (OR = 0.69, 95% CI: 0.30–1.60). Among former smokers, lower education indicated higher ORs for both e-cigarettes and heat-not-burn tobacco ever

Citrate-capped gold nanoparticle electrophoretic heat production in response to a time-varying radiofrequency electric-field.

Science.gov (United States)

Corr, Stuart J; Raoof, Mustafa; Mackeyev, Yuri; Phounsavath, Sophia; Cheney, Matthew A; Cisneros, Brandon T; Shur, Michael; Gozin, Michael; McNally, Patrick J; Wilson, Lon J; Curley, Steven A

2012-11-15

The evaluation of heat production from gold nanoparticles (AuNPs) irradiated with radiofrequency (RF) energy has been problematic due to Joule heating of their background ionic buffer suspensions. Insights into the physical heating mechanism of nanomaterials under RF excitations must be obtained if they are to have applications in fields such as nanoparticle-targeted hyperthermia for cancer therapy. By developing a purification protocol which allows for highly-stable and concentrated solutions of citrate-capped AuNPs to be suspended in high-resistivity water, we show herein, for the first time, that heat production is only evident for AuNPs of diameters ≤ 10 nm, indicating a unique size-dependent heating behavior not previously observed. Heat production has also shown to be linearly dependent on both AuNP concentration and total surface area, and severely attenuated upon AuNP aggregation. These relationships have been further validated using permittivity analysis across a frequency range of 10 MHz to 3 GHz, as well as static conductivity measurements. Theoretical evaluations suggest that the heating mechanism can be modeled by the electrophoretic oscillation of charged AuNPs across finite length scales in response to a time-varying electric field. It is anticipated these results will assist future development of nanoparticle-assisted heat production by RF fields for applications such as targeted cancer hyperthermia.

Differences in response to heat stress due to production level and breed of dairy cows

Science.gov (United States)

Gantner, Vesna; Bobic, Tina; Gantner, Ranko; Gregic, Maja; Kuterovac, Kresimir; Novakovic, Jurica; Potocnik, Klemen

2017-09-01

The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

Exergetic life cycle assessment of cement production process with waste heat power generation

International Nuclear Information System (INIS)

Sui, Xiuwen; Zhang, Yun; Shao, Shuai; Zhang, Shushen

2014-01-01

Highlights: • Exergetic life cycle assessment was performed for the cement production process. • Each system’s efficiency before and after waste heat power generation was analyzed. • The waste heat power generation improved the efficiency of each production system. • It provided technical support for the implementation of energy-saving schemes. - Abstract: The cement industry is an industry that consumes a considerable quantity of resources and energy and has a very large influence on the efficient use of global resources and energy. In this study, exergetic life cycle assessment is performed for the cement production process, and the energy efficiency and exergy efficiency of each system before and after waste heat power generation is investigated. The study indicates that, before carrying out a waste heat power generation project, the objective energy efficiencies of the raw material preparation system, pulverized coal preparation system and rotary kiln system are 39.4%, 10.8% and 50.2%, respectively, and the objective exergy efficiencies are 4.5%, 1.4% and 33.7%, respectively; after carrying out a waste heat power generation project, the objective energy efficiencies are 45.8%, 15.5% and 55.1%, respectively, and the objective exergy efficiencies are 7.8%, 2.8% and 38.1%, respectively. The waste heat power generation project can recover 3.7% of the total input exergy of a rotary kiln system and improve the objective exergy efficiencies of the above three systems. The study can identify degree of resource and energy utilization and the energy-saving effect of a waste heat power generation project on each system, and provide technical support for managers in the implementation of energy-saving schemes

Catalyzed deuterium-deuterium and deuterium-tritium fusion blankets for high temperature process heat production

International Nuclear Information System (INIS)

Ragheb, M.M.H.; Salimi, B.

1982-01-01

Tritiumless blanket designs, associated with a catalyzed deuterium-deuterium (D-D) fusion cycle and using a single high temperature solid pebble or falling bed zone, for process heat production, are proposed. Neutronics and photonics calculations, using the Monte Carlo method, show that an about 90% heat deposition fraction is possible in the high temperature zone, compared to a 30 to 40% fraction if a deuterium-tritium (D-T) fusion cycle is used with separate breeding and heat deposition zones. Such a design is intended primarily for synthetic fuels manufacture through hydrogen production using high temperature water electrolysis. A system analysis involving plant energy balances and accounting for the different fusion energy partitions into neutrons and charged particles showed that plasma amplification factors in the range of 2 are needed. In terms of maximization of process heat and electricity production, and the maximization of the ratio of high temperature process heat to electricity, the catalyzed D-D system outperforms the D-T one by about 20%. The concept is thought competitive to the lithium boiler concept for such applications, with the added potential advantages of lower tritium inventories in the plasma, reduced lithium pumping (in the case of magnetic confinement) and safety problems, less radiation damage at the first wall, and minimized risks of radioactive product contamination by tritium

Volatile production during preignition heating. Final technical report, 15 September 1980-30 September 1982

Energy Technology Data Exchange (ETDEWEB)

Ballantyne, A.; Chou, H.; Flusberg, A.; Neoh, K.; Orozco, N.; Stickler, D.

1983-10-01

Pulverized coal particles, in a flowing inert nitrogen stream, have been heated by high power Carbon Dioxide Laser. The consequence of such an irradiation have proved to be both novel and surprising as a result of the rapid quenching of primary coal products. It ahs been found that the gas phase yield from such heating (typically, temperatures in excess of 1400 K at rates approx. 2 x 10/sup 5/ K/s) is very small (< 0.2 percent of coal carbon and hydrogen). Analysis of the solid residue has shown the presence of fine lacy particulate chains of material of 0.1 ..mu..m diameter, which appears to be soluble in tetrahydrofuran. The yields of solute were significantly much higher than for raw coals. Molecular weight of the solute material was high, being in the range of 600 to 3000. The above and substantiating evidence point to a new mechanism of high heating rate pyrolysis in which only tar-like materials are produced as primary products from the coal. It is hypothesized that gas phase products are primarily the result of secondary reactions of these primary products in the hot gas environments usually employed by other heating techniques.

Heat supply analysis of steam reforming hydrogen production process in conventional and nuclear

International Nuclear Information System (INIS)

Siti Alimah; Djati Hoesen Salimy

2015-01-01

Tile analysis of heat energy supply in the production of hydrogen by natural gas steam reforming process has been done. The aim of the study is to compare the energy supply system of conventional and nuclear heat. Methodology used in this study is an assessment of literature and analysis based on the comparisons. The study shows that the heat sources of fossil fuels (natural gas) is able to provide optimum operating conditions of temperature and pressure of 850-900 °C and 2-3 MPa, as well as the heat transfer is dominated by radiation heat transfer, so that the heat flux that can be achieved on the catalyst tube relatively high (50-80 kW/m"2) and provide high thermal efficiency of about 85 %. While in the system with nuclear energy, due to the demands of safety, process operating at less than optimum conditions of temperature and pressure of 800-850 °C and 4.5 MPa, as well as the heat transfer is dominated by convection heat transfer, so that the heat flux that can be achieved catalyst tube is relatively low (1020 kW/m"2) and it provides a low thermal efficiency of about 50 %. Modifications of reformer and heat utilization can increase the heat flux up to 40 kW/m"2 so that the thermal efficiency can reach 78 %. Nevertheless, the application of nuclear energy to hydrogen production with steam reforming process is able to reduce the burning of fossil fuels which has implications for the potential decrease in the rate of CO2 emissions into the environment. (author)

Effects of Heat Stress on Construction Labor Productivity in Hong Kong: A Case Study of Rebar Workers

OpenAIRE

Yi, Wen; Chan, Albert P. C.

2017-01-01

Global warming is bringing more frequent and severe heat waves, and the result will be serious for vulnerable populations such as construction workers. Excessive heat stress has profound effects on physiological responses, which cause occupational injuries, fatalities and low productivity. Construction workers are particularly affected by heat stress, because of the body heat production caused by physically demanding tasks, and hot and humid working conditions. Field studies were conducted be...

Comparison of microwave and conduction-convection heating autohydrolysis pretreatment for bioethanol production.

Science.gov (United States)

Aguilar-Reynosa, Alejandra; Romaní, Aloia; Rodríguez-Jasso, Rosa M; Aguilar, Cristóbal N; Garrote, Gil; Ruiz, Héctor A

2017-11-01

This work describes the application of two forms of heating for autohydrolysis pretreatment on isothermal regimen: conduction-convection heating and microwave heating processing using corn stover as raw material for bioethanol production. Pretreatments were performed using different operational conditions: residence time (10-50 min) and temperature (160-200°C) for both pretreatments. Subsequently, the susceptibility of pretreated solids was studied using low enzyme loads, and high substrate loads. The highest conversion was 95.1% for microwave pretreated solids. Also solids pretreated by microwave heating processing showed better ethanol conversion in simultaneous saccharification and fermentation process (92% corresponding to 33.8g/L). Therefore, microwave heating processing is a promising technology in the pretreatment of lignocellulosic materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production planning of combined heat and power plants with regards to electricity price spikes : A machine learning approach

OpenAIRE

Fransson, Nathalie

2017-01-01

District heating systems could help manage the expected increase of volatility on the Nordic electricity market by starting a combined heat and power production plant (CHP) instead of a heat only production plant when electricity prices are expected to be high. Fortum Värme is interested in adjusting the production planning of their district heating system more towards high electricity prices and in their system there is a peak load CHP unit that could be utilised for this purpose. The econom...

Application of biogas for combined heat and power production in the rural region

International Nuclear Information System (INIS)

Kozak, T.; Majchrzycka, A.

2009-01-01

The paper discusses combined production of heat and power (CHP) from biogas in a small-scale power plant placed in the rural region. Based on power and heat demands of the rural region and biomass supply, the CHP system was selected. Keywords: biogas, cogeneration

Fuel production from coal by the Mobil Oil process using nuclear high-temperature process heat

International Nuclear Information System (INIS)

Hoffmann, G.

1982-01-01

Two processes for the production of liquid hydrocarbons are presented: Direct conversion of coal into fuel (coal hydrogenation) and indirect conversion of coal into fuel (syngas production, methanol synthesis, Mobil Oil process). Both processes have several variants in which nuclear process heat may be used; in most cases, the nuclear heat is introduced in the gas production stage. The following gas production processes are compared: LURGI coal gasification process; steam reformer methanation, with and without coal hydrogasification and steam gasification of coal. (orig./EF) [de

Heat exposure and productivity in orchards: Implications for climate change research.

Science.gov (United States)

Quiller, Grant; Krenz, Jennifer; Ebi, Kristie; Hess, Jeremy J; Fenske, Richard A; Sampson, Paul D; Pan, Mengjie; Spector, June T

2017-11-02

Recent studies suggest that heat exposure degrades work productivity, but such studies have not considered individual- and workplace-level factors. Forty-six tree-fruit harvesters (98% Latino/a) from 6 orchards participated in a cross-sectional study in central/eastern Washington in 2015. The association between maximum measured work-shift wet-bulb globe temperature (WBGT max ) and productivity (total weight of fruit bins collected per time worked) was estimated using linear mixed-effects models, adjusting for relevant confounders. The mean (standard deviation) WBGT max was 27.9°C (3.6°C) in August and 21.2°C (2.0°C) in September. There was a trend of decreasing productivity with increasing WBGT max , but this association was not statistically significant. When individual- and workplace-level factors were included in the model, the association approached the null. Not considering individual, work, and economic factors that affect rest and recovery in projections of the effects of climate change could result in overestimates of reductions in future productivity and underestimate risk of heat illness.

Environmental performance of Miscanthus as a fuel alternative for district heat production

DEFF Research Database (Denmark)

Parajuli, Ranjan; Sperling, K.; Dalgaard, Tommy

2015-01-01

scenarios: (i) in Combined Heat and Power (CHP) plant and (ii) in a Boiler (producing heat only). Biomass conversion to heat is also compared with the conversion of natural gas (NG). The environmental impact categories considered for the assessment are: Global Warming Potential (GWP), Non-Renewable Energy......This study discusses about the environmental performance of Miscanthus conversion to district heat. Life Cycle Impact Assessment (LCIA) is used as a tool to assess the environmental impacts related to the biomass conversion to heat. Energy conversion of Miscanthus is compared in two combustion...... (NRE) use and Land use (LU). The current study revealed that for 1 MJ of heat production, Miscanthus fired in the CHP plant would lead to a GWP at −0.071 kg CO2-eq, an NRE use −0.767-MJ primary, and LU 0.09 m2-a (square metre-annual). For the same heat output, Miscanthus fired in the boiler would lead...

Evaluation of opportunities for heat integration of biomass-based Fischer–Tropsch crude production at Scandinavian kraft pulp and paper mill sites

International Nuclear Information System (INIS)

Ljungstedt, Hanna; Pettersson, Karin; Harvey, Simon

2013-01-01

This study investigates heat integrated production of FT (Fischer–Tropsch) crude, where excess heat from the FT crude plant is delivered to a typical Scandinavian pulp and paper mill that produces fine paper. The sizes of FT crude plants are quantified, when the amount of excess heat from the FT plant exactly matches the heating demand otherwise satisfied by the bark boiler at the mill, considering a number of development pathways at the mill, including various degrees of steam savings and biorefinery options, such as lignin extraction. Performance of integrated production is compared with that of an FT stand-alone plant on the basis of wood fuel-to-FT crude efficiency, GHG (greenhouse gas) emissions balances and FT crude production cost. The results show that there exists a heat integration opportunity for an FT crude plant ranging from 0 up to 350 MW (LHV) of wood fuel depending on the development pathway for the mill. The results indicate higher overall efficiency and a generally lower production cost for the heat integrated, co-located production. Heat integrated production has a larger potential to contribute to GHG emission mitigation, assuming a future generation of grid electricity emitting equal to or less than an NGCC (natural gas combined cycle) power plant. - Highlights: • We investigate opportunities for heat integrated FT crude production at a mill. • Typical kraft pulp and paper mills have a potential for heat integrated production. • We compare the heat integrated production with stand-alone FT crude production. • Higher efficiency and lower production cost for heat integrated production. • Reduction of GHG emissions is strongly dependent on grid electricity emissions

Some characteristics of heat production by stationary parabolic, cylindrical solar concentrator

Energy Technology Data Exchange (ETDEWEB)

Bojic, M.; Marjanovic, N.; Miletic, I.; Mitic, A. [Kragujevac Univ., Kragujevac (Serbia). Faculty of Mechanical Engineering; Stefanovic, V. [Nis Univ., Nis (Serbia). Faculty of Mechanical Engineering

2009-07-01

The use of solar energy for heating, cooling and electricity production was discussed with particular reference to the use of a stationary, asymmetric solar concentrator for conversion of solar energy to heat using a reflector and absorber. The infinite length CP-0A type stationary parabolic, cylindrical solar concentrator for heat production consists of the absorber (with water pipes) and parabolic, cylindrical reflector (with a metal surface). It has a geometrical concentration ratio of up to 4. This paper reported on a study that used the CATIA computer software to investigate how direct solar radiation approaches the concentrator aperture and the concentrator reflector. The propagation of light rays inside the concentrator to reach the absorber surface was examined. The study showed that the solar ray either hits the absorber directly or it bounces one or several time from the concentrator reflector. The efficiency of light rays was also calculated as a function of angles of incident of solar rays and type of reflector surface. 5 refs., 8 figs.

Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp

Science.gov (United States)

2013-01-01

Background The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Results Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. Conclusions To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with

Hydrogen production by high-temperature gas-cooled reactor. Conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system

International Nuclear Information System (INIS)

Sakaba, Nariaki; Ohashi, Hirofumi; Sato, Hiroyuki; Hara, Teruo; Kato, Ryoma; Kunitomi, Kazuhiko

2008-01-01

Nuclear hydrogen production is necessary in an anticipated hydrogen society that demands a massive quantity of hydrogen without economic disadvantage. Japan Atomic Energy Agency (JAEA) has launched the conceptual design study of a hydrogen production system with a near-term plan to connect it to Japan's first high-temperature gas-cooled reactor HTTR. The candidate hydrogen production system is based on the thermochemical water-splitting iodine sulphur (IS) process.The heat of 10 MWth at approximately 900degC, which can be provided by the secondary helium from the intermediate heat exchanger of the HTTR, is the energy input to the hydrogen production system. In this paper, we describe the recent progresses made in the conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system. A new concept of sulphuric acid decomposer is proposed. This involves the integration of three separate functions of sulphuric acid decomposer, sulphur trioxide decomposer, and process heat exchanger. A new mixer-settler type of Bunsen reactor is also designed. This integrates three separate functions of Bunsen reactor, phase separator, and pump. The new concepts are expected to result in improved economics through construction and operation cost reductions because the number of process equipment and complicated connections between the equipment has been substantially reduced. (author)

Heat exposure, cardiovascular stress and work productivity in rice harvesters in India: implications for a climate change future.

Science.gov (United States)

Sahu, Subhashis; Sett, Moumita; Kjellstrom, Tord

2013-01-01

Excessive workplace heat exposures create well-known risks of heat stroke, and it limits the workers' capacity to sustain physical activity. There is very limited evidence available on how these effects reduce work productivity, while the quantitative relationship between heat and work productivity is an essential basis for climate change impact assessments. We measured hourly heat exposure in rice fields in West Bengal and recorded perceived health problems via interviews of 124 rice harvesters. In a sub-group (n = 48) heart rate was recorded every minute in a standard work situation. Work productivity was recorded as hourly rice bundle collection output. The hourly heat levels (WBGT = Wet Bulb Globe Temperature) were 26-32°C (at air temperatures of 30-38°C), exceeding international standards. Most workers reported exhaustion and pain during work on hot days. Heart rate recovered quickly at low heat, but more slowly at high heat, indicating cardiovascular strain. The hourly number of rice bundles collected was significantly reduced at WBGT>26°C (approximately 5% per°C of increased WBGT). We conclude that high heat exposure in agriculture caused heat strain and reduced work productivity. This reduction will be exacerbated by climate change and may undermine the local economy.

Heat pumps in district heating networks

DEFF Research Database (Denmark)

Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

High temperature corrosion in the thermochemical hydrogen production from nuclear heat

International Nuclear Information System (INIS)

Coen-Porisini, F.; Imarisio, G.

1976-01-01

In the production of hydrogen by water decomposition utilizing nuclear heat, a multistep process has to be employed. Water and the intermediate chemical products reach in chemical cycles giving hydrogen and oxygen with regeneration of the primary products used. Three cycles are examined, characterized by the presence of halide compounds and particularly hydracids at temperatures up to 800 0 C. Corrosion tests were carried out in hydrobromic acid, hydrochloric acid, ferric chloride solutions, and hydriodic acid

Domestic Hot Water Production with Ground Source Heat Pump in Apartment Buildings

Directory of Open Access Journals (Sweden)

Jukka Yrjölä

2015-08-01

Full Text Available Producing domestic hot water (DHW with a ground source heat pump (GSHP is challenging due to the high temperature (HT of DHW. There are many studies proving the better performance of cascade heat pumps compared to single-stage heat pumps when the difference between the condensing and the evaporation temperature is large. In this system approach study, different GSHP arrangements are described and computationally compared. A two-stage heat pump arrangement is introduced in which water tanks of the heating system are utilized for warming up the DHW in two stages. It is shown that the electricity consumption with this two-stage system is approximately 31% less than with the single-stage heat pump and 12% less than with the cascade system. Further, both low temperature (LT and HT heat pumps can run alone, which is not common in cascade or other two-stage heat pumps. This is advantageous because the high loads of the space heating and DHW production are not simultaneous. Proper insulation of the DHW and recirculation pipe network is essential, and drying towel rails or other heating coils should be avoided when aiming for a high efficiency. The refrigerants in the calculations are R407C for the LT heat pump and R134a for the HT heat pump. Investment costs are excluded from calculations.

Steam condensation process in a power production cycle and heat exchanger for it

International Nuclear Information System (INIS)

Tondeur, Gerard; Andro, Jean; Marjollet, Jacques; Pouderoux, Pierre.

1982-01-01

Steam condensation process in a power production cycle by expansion in turbines, characterized by the fact that this condensation is performed by the vaporization of a coolant with a vaporization temperature at atmospheric pressure lower than that of water, and that the vaporized coolant fluid is expanded in a turbine and then condensed by heat exchange with cold water being heated, while the liquefied coolant is recompressed and used for heat exchange with the steam to be condensed [fr

Sensitivity and uncertainty analysis for fission product decay heat calculations

International Nuclear Information System (INIS)

Rebah, J.; Lee, Y.K.; Nimal, J.C.; Nimal, B.; Luneville, L.; Duchemin, B.

1994-01-01

The calculated uncertainty in decay heat due to the uncertainty in basic nuclear data given in the CEA86 Library, is presented. Uncertainties in summation calculation arise from several sources: fission product yields, half-lives and average decay energies. The correlation between basic data is taken into account. The uncertainty analysis were obtained for thermal-neutron-induced fission of U235 and Pu239 in the case of burst fission and irradiation time. The calculated decay heat in this study is compared with experimental results and with new calculation using the JEF2 Library. (from authors) 6 figs., 19 refs

Critical factors for profitable combined production of heat, power and biofuels; Kritiska faktorer foer loensam produktion i bioenergikombinat

Energy Technology Data Exchange (ETDEWEB)

Nohlgren, Ingrid; Gunnarsson, Emma; Lundqvist, Per; Stigander, Haakan; Widmark, Annika (AaF, Stockholm (Sweden))

2012-02-15

During the last 5-10 years, research and development efforts have been made in the field of polygeneration of heat and power with production of 'other green' products such as transport fuels or wood pellets. The driving force for heat and power producers is the potential of increased profitability through additional sales of heat. The driving force for wood pellet and some transport fuel producers is the potential of low cost process steam or heat. However, in the case of gasification based transport fuel production processes the situation is different. The process generates a surplus of heat, which can benefit from the proximity of a district heating net. In addition, some polygeneration combinations could provide other advantages such as more efficient raw material handling. Together with these driving forces, the EU renewable energy directive (which targets 10 % renewable energy use in the transport sector by 2020), shows that the market for production of renewable transport fuel is expanding. To refine Swedish biomass resources to more highly valuable products such as wood pellets or renewable transport fuels would maintain industry and employment opportunities within Sweden and at the same time fulfils the international and national climate targets. The overall aim with this project is to describe the factors which are crucial for the opportunity for profitable polygeneration of heat, power and wood pellets or renewable transport fuels and how these factors influence the location of such a plant within Sweden. The important factors can be categorized as: (1) Supply of raw material, (2) distribution of raw material and products, (3) Demand of products and (4) Integration between the different plants. In this project, only general aspects are described and should be seen as guidance for the industry (both energy and forest industry) which has an interest in polygeneration. The project gives an overview of different possibilities, opportunities and

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

Science.gov (United States)

Sibille, Laurent; Dominques, Jesus A.

2012-01-01

The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

Heat production and body temperature during cooling and rewarming in overweight and lean men.

Science.gov (United States)

Claessens-van Ooijen, Anne M J; Westerterp, Klaas R; Wouters, Loek; Schoffelen, Paul F M; van Steenhoven, Anton A; van Marken Lichtenbelt, Wouter D

2006-11-01

To compare overweight and lean subjects with respect to thermogenesis and physiological insulation in response to mild cold and rewarming. Ten overweight men (mean BMI, 29.2 +/- 2.8 kg/m(2)) and 10 lean men (mean BMI, 21.1 +/- 2.0 kg/m(2)) were exposed to cold air for 1 hour, followed by 1 hour of rewarming. Body composition was determined by hydrodensitometry and deuterium dilution. Heat production and body temperatures were measured continuously by indirect calorimetry and thermistors, respectively. Muscle activity was recorded using electromyography. In both groups, heat production increased significantly during cooling (lean, p = 0.004; overweight, p = 0.006). The increase was larger in the lean group compared with the overweight group (p = 0.04). During rewarming, heat production returned to baseline in the overweight group and stayed higher compared with baseline in the lean group (p = 0.003). The difference in heat production between rewarming and baseline was larger in the lean (p = 0.01) than in the overweight subjects. Weighted body temperature of both groups decreased during cold exposure (lean, p = 0.002; overweight, p < 0.001) and did not return to baseline during rewarming. Overweight subjects showed a blunted mild cold-induced thermogenesis. The insulative cold response was not different among the groups. The energy-efficient response of the overweight subjects can have consequences for energy balance in the long term. The results support the concept of a dynamic heat regulation model instead of temperature regulation around a fixed set point.

Deriving heat production from gaseous exchange: validity of the approach

NARCIS (Netherlands)

Gerrits, W.J.J.; Borne, van den J.J.G.C.; Labussière, E.

2015-01-01

The use of indirect calorimetry as a means to quantify heat production (Q) and net substrate oxidation has increased rapidly since the pioneering work of Lavoisier, and today, indirect calorimetry is often used as a reference for other measures of Q. Simple equations were developed and widely

Heat production during contraction in skeletal muscle of hypothyroid mice

International Nuclear Information System (INIS)

Leijendekker, W.J.; van Hardeveld, C.; Elzinga, G.

1987-01-01

The effect of hypothyroidism on tension-independent and -dependent heat produced during a twitch and a tetanic contraction of extensor digitorum longus (EDL) and soleus muscle of mice was examined. The amount of heat produced during a twitch and the rate of heat development during a tetanus of EDL and soleus were measured at and above optimal length. The effect of hypothyroidism on force production was 2+ cycling, these findings suggest that ATP splitting due to the Ca 2+ cycling is reduced in hypothyroid mice. This conclusion was strengthened by the observation that the oxalate-supported 45 Ca 2+ -uptake activity and 45 Ca 2+ -loading capacity of muscle homogenates from hypothyroid mice were reduced, respectively, to 51 and to 65% in soleus and to 63 and 73% in EDL muscle as compared with euthyroid mice. The tension-dependent rate of heat development during a tetanus was also decreased in soleus muscle of hypothyroid mice. This suggests a lower rate of ATP hydrolysis related to cross-bridge cycling in this muscle due to the hypothyroid state

Uranium, Thorium and Potassium concentrations and volumetric heat production rates at the eastern border of the Parana basin

International Nuclear Information System (INIS)

Andrade, Telma C.Q.; Ribeiro, Fernando B.

1997-01-01

Uranium, thorium and potassium concentrations were measured and volumetric heat production rates were calculated for rocks from the exposed basement at the eastern-southeastern border of the Parana Basin between 23 deg S and 32 deg S. Heat generating element concentration data available in the literature were also used when possible, for volumetric heat production calculations. The uranium concentrations vary from below determination limit (0.51 ppm) and 16 ppm whereas the thorium concentrations vary from below the determination limit (1.26 ppm) and 68 ppm, and K concentrations vary between 0.08% and 5.6%. Volumetric heat production rates vary between 0.07 μW/m 3 to 6.2 μW/m 3 , and the obtained results show a variable heat generation rate with high heat producing bodies scattered along this Parana Basin border. The higher observed values concentrate in the Ribeira fold belt at about 23 deg S and between 30 deg S and 32 deg S in the Down Feliciano fold belt. Isolated high heat production rates can also be observed between 26 deg S and 28 deg S. (author). 11 refs., 3 tabs

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

DEFF Research Database (Denmark)

Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

2014-01-01

production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible...... district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the expected operation pattern of such polygeneration system is taken......Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol...

Production Planning with Respect to Uncertainties. Simulator Based Production Planning of Average Sized Combined Heat and Power Production Plants; Produktionsplanering under osaekerhet. Simulatorbaserad produktionsplanering av medelstora kraftvaermeanlaeggningar

Energy Technology Data Exchange (ETDEWEB)

Haeggstaahl, Daniel [Maelardalen Univ., Vaesteraas (Sweden); Dotzauer, Erik [AB Fortum, Stockholm (Sweden)

2004-12-01

Production planning in Combined Heat and Power (CHP) systems is considered. The focus is on development and use of mathematical models and methods. Different aspects on production planning are discussed, including weather and load predictions. Questions relevant on the different planning horizons are illuminated. The main purpose with short-term (one week) planning is to decide when to start and stop the production units, and to decide how to use the heat storage. The main conclusion from the outline of pros and cons of commercial planning software are that several are using Mixed Integer Programming (MIP). In that sense they are similar. Building a production planning model means that the planning problem is formulated as a mathematical optimization problem. The accuracy of the input data determines the practical detail level of the model. Two alternatives to the methods used in today's commercial programs are proposed: stochastic optimization and simulator-based optimization. The basic concepts of mathematical optimization are outlined. A simulator-based model for short-term planning is developed. The purpose is to minimize the production costs, depending on the heat demand in the district heating system, prices of electricity and fuels, emission taxes and fees, etc. The problem is simplified by not including any time-linking conditions. The process model is developed in IPSEpro, a heat and mass-balance software from SimTech Simulation Technology. TOMLAB, an optimization toolbox in MATLAB, is used as optimizer. Three different solvers are applied: glcFast, glcCluster and SNOPT. The link between TOMLAB and IPSEpro is accomplished using the Microsoft COM technology. MATLAB is the automation client and contains the control of IPSEpro and TOMLAB. The simulator-based model is applied to the CHP plant in Eskilstuna. Two days are chosen and analyzed. The optimized production is compared to the measured. A sensitivity analysis on how variations in outdoor

Utilization of low-temperature heat sources for heat and power production

DEFF Research Database (Denmark)

Haglind, Fredrik; Elmegaard, Brian

2014-01-01

Low-temperature heat sources are available in many applications, ranging from waste heat from marine diesel engines, industries and refrigeration plants to biomass, geothermal and solar heat sources. There is a great potential for enhancing the utilization of these heat sources by novel...

Properties of Fission-Product decay heat from Minor-Actinide fissioning systems

International Nuclear Information System (INIS)

Oyamatsu, Kazuhiro; Mori, Hideki

2000-01-01

The aggregate Fission-Product (FP) decay heat after a pulse fission is examined for Minor Actinide (MA) fissiles 237 Np, 241 Am, 243 Am, 242 Cm and 244 Cm. We find that the MA decay heat is comparable but smaller than that of 235 U except for cooling times at about 10 8 s (approx. = 3 y). At these cooling times, either the β or γ component of the FP decay heat for these MA's is substantially larger than the one for 235 U. This difference is found to originate from the cumulative fission yield of 106 Ru (T 1/2 = 3.2x10 7 s). This nuclide is the parent of 106 Rh (T 1/2 = 29.8 s) which is the dominant source of the decay heat at 10 8 s (approx. = 3 y). The fission yield is nearly an increasing function of the fissile mass number so that the FP decay heat is the largest for 244 Cm among the MA's at the cooling time. (author)

Climate change projections of heat stress in Europe: From meteorological variables to impacts on productivity

Science.gov (United States)

Casanueva, Ana; Kotlarski, Sven; Liniger, Mark A.

2017-04-01

Future climate change is likely to have important impacts in many socio-economic sectors. In particular, higher summer temperatures or more prolonged heat waves may be responsible for health problems and productivity losses related to heat stress, especially affecting people exposed to such situations (e.g. working under outside settings or in non-acclimatized workplaces). Heat stress on the body under work load and consequently their productivity loss can be described through heat stress indices that are based on multiple meteorological parameters such as temperature, humidity, wind and radiation. Exploring the changes of these variables under a warmer climate is of prime importance for the Impacts, Adaptation and Vulnerability communities. In particular, the H2020 project HEAT-SHIELD aims at analyzing the impact of climate change on heat stress in strategic industries in Europe (manufacturing, construction, transportation, tourism and agriculture) within an inter-sectoral framework (climate scientists, biometeorologists, physiologists and stakeholders). In the present work we explore present and future heat stress over Europe using an ensemble of the state-of-the-art RCMs from the EURO-CORDEX initiative. Since RCMs cannot be directly used in impact studies due to their partly substantial biases, a standard bias correction method (empirical quantile mapping) is applied to correct the individual variables that are then used to derive heat stress indices. The objectives of this study are twofold, 1) to test the ability of the separately bias corrected variables to reproduce the main characteristics of heat stress indices in present climate conditions and 2) to explore climate change projections of heat stress indices. We use the wet bulb globe temperature (WBGT) as primary heat stress index, considering two different versions for indoor (or in the shade, based on temperature and humidity conditions) and outdoor settings (including also wind and radiation). The WBGT

Determination of thermal characteristics of combustion products of fire-tube heat generator with flow turbulator

OpenAIRE

Lukjanov Alexander V.; Ostapenko Dmitry V.; Basist Dmitry V.

2014-01-01

Boiler construction is one of the major industries of any state. The aim is to determine the effect of the turbulator on the intensity of heat transfer in the convective part of the fire-tube heat generator of domestic production. The improvement of convective heating surfaces is one of the ways to increase the energy efficiency of the fire-tube heat generator. Since model of the process of heat transfer of gas flow in the convective tubes is multifactorial and does not have clear analytical ...

Mathematical modelling of heat production in deep geological repository of high-level nuclear waste

International Nuclear Information System (INIS)

Kovanda, O.

2017-01-01

Waste produced by nuclear industry requires special handling. Currently, there is a research taking place, focused at possibilities of nuclear waste storage in deep geological repositories, hosted in stable geological environment. The high-level nuclear waste produces significant amount of heat for a long time, which can affect either environment outside of or within the repository in a negative way. Therefore to reduce risks, it is desirable to know the principles of such heat production, which can be achieved using mathematical modeling. This thesis comes up with a general model of heat production-time dependency, dependable on initial composition of the waste. To be able to model real situations, output of this thesis needs to be utilized in an IT solution. (authors)

Validation of accuracy and stability of numerical simulation for 2-D heat transfer system by an entropy production approach

Directory of Open Access Journals (Sweden)

Brohi Ali Anwar

2017-01-01

Full Text Available The entropy production in 2-D heat transfer system has been analyzed systematically by using the finite volume method, to develop new criteria for the numerical simulation in case of multidimensional systems, with the aid of the CFD codes. The steady-state heat conduction problem has been investigated for entropy production, and the entropy production profile has been calculated based upon the current approach. From results for 2-D heat conduction, it can be found that the stability of entropy production profile exhibits a better agreement with the exact solution accordingly, and the current approach is effective for measuring the accuracy and stability of numerical simulations for heat transfer problems.

Modeling the Daly Gap: The Influence of Latent Heat Production in Controlling Magma Extraction and Eruption

Science.gov (United States)

Nelson, B. K.; Ghiorso, M. S.; Bachmann, O.; Dufek, J.

2011-12-01

A century-old issue in volcanology is the origin of the gap in chemical compositions observed in magmatic series on ocean islands and arcs - the "Daly Gap". If the gap forms during differentiation from a mafic parent, models that predict the dynamics of magma extraction as a function of chemical composition must simulate a process that results in volumetrically biased, bimodal compositions of erupted magmas. The probability of magma extraction is controlled by magma dynamical processes, which have a complex response to magmatic heat evolution. Heat loss from the magmatic system is far from a simple, monotonic function of time. It is modified by the crystallization sequence, chamber margin heat flux, and is buffered by latent heat production. We use chemical and thermal calculations of MELTS (Ghiorso & Sack, 1995) as input to the physical model of QUANTUM (Dufek & Bachmann, 2010) to predict crystallinity windows of most probable magma extraction. We modeled two case studies: volcanism on Tenerife, Canary Islands, and the Campanian Ignimbrite (CI) of Campi Flegrei, Italy. Both preserve a basanitic to phonolitic lineage and have comparable total alkali concentrations; however, CI has high and Tenerife has low K2O/Na2O. Modeled thermal histories of differentiation for the two sequences contrast strongly. In Tenerife, the rate of latent heat production is almost always greater than sensible heat production, with spikes in the ratio of latent to sensible heats of up to 40 associated with the appearance of Fe-Ti oxides at near 50% crystallization. This punctuated heat production must cause magma temperature change to stall or slow in time. The extended time spent at ≈50% crystallinity, associated with dynamical processes that enhance melt extraction near 50% crystallinity, suggests the magma composition at this interval should be common. In Tenerife, the modeled composition coincides with that of the first peak in the bimodal frequency-composition distribution. In our

Estimate of thermoelastic heat production from superconducting composites in pulsed poloidal coil systems

International Nuclear Information System (INIS)

Ballou, J.K.; Gray, W.H.

1976-01-01

In the design of the cryogenic system and superconducting magnets for the poloidal field system in a tokamak, it is important to have an accurate estimate of the heat produced in superconducting magnets as a result of rapidly changing magnetic fields. A computer code, PLASS (Pulsed Losses in Axisymmetric Superconducting Solenoids), was written to estimate the contributions to the heat production from superconductor hysteresis losses, superconductor coupling losses, stabilizing material eddy current losses, and structural material eddy current losses. Recently, it has been shown that thermoelastic dissipation in superconducting composites can contribute as much to heat production as the other loss mechanisms mentioned above. A modification of PLASS which takes into consideration thermoelastic dissipation in superconducting composites is discussed. A comparison between superconductor thermoelastic dissipation and the other superconductor loss mechanisms is presented in terms of the poloidal coil system of the ORNL Experimental Power Reactor design

Geographical influence of heat stress on milk production of Holstein ...

African Journals Online (AJOL)

To model the influence of heat stress on milk production of Holstein dairy herds on pasture in South Africa, the maximum entropy (Maxent) modelling technique was used in a novel approach to model and map optimal milk-producing areas. Geographical locations of farms with top milk-producing Holstein herds on pasture ...

The small-scale production of hydrogen, with the co-production of electricity and district heat, by means of the gasification of municipal solid waste

International Nuclear Information System (INIS)

Hognert, Johannes; Nilsson, Lars

2016-01-01

Highlights: • Outline of a process for handling municipal solid waste potentially leading to reduced use of fossil transportation fuels. • The integration of waste gasification into a district heat plant leads to excellent energy efficiency. • Analysis based on actual production data from a district heat plant over the period of one year. • Simulation of a plant with productions of heat, power and gaseous hydrogen. - Abstract: Reducing the use of fossil fuels and increasing the recycling of waste are two important challenges for a sustainable society. Fossil fuels contribute to global warming whilst waste causes the pollution of land, water and air. Alternative fuels and innovative waste management systems are needed to address these issues. In this study a gasification process, fuelled with municipal solid waste, was assumed to be integrated into a heat plant to produce hydrogen, electricity and district heat. A whole system, which includes a gasification reactor, heat plant, steam cycle, pressure swing adsorption, gas turbine and compressors was modelled in Microsoft Excel and an energy balance of the system was solved. Data from the scientific literature were used when setting up the heat and mass balances of the gasification process as well as for assessment of the composition of the syngas. The allocation of energy of the products obtained in the process is 29% hydrogen, 26% electricity and 45% district heat. A significant result of the study is the high energy efficiency (88%) during the cold period of the year when the produced heat in the system is utilized for district heat. The system also shows a competitive energy efficiency (56.5%) all year round.

Heat production and quantitative oxidation of nutrients by physical activity in pigs

DEFF Research Database (Denmark)

Jakobsen, K; Chwalibog, André; Henckel, S

1994-01-01

Two groups of pigs weighing 90 (Expt A) or 80 (Expt B) kg walked on a horizontal moving rubber belt for a distance of 315 m at a speed of 25.6 +/- 0.38 and 28.8 +/- 0.35 m/min respectively for 10 min in an open-air-circuit respiration unit. From measurements of VO2 and VCO2, heat production...... and oxidation of carbohydrate and fat were calculated 30 min before (I), 10 min during walking (II) and in intervals of 10 min (III, IV) and 30 min (V) after walking. Heat production increased 2-3 times in section II in relation to section I, remained high for 20 min in section III and IV, but reached the basal...

An Analysis of the Impact of Heat Waves in Labor and Crop Productivity in the Agricultural Sector in California

Science.gov (United States)

Castillo, F.; Wehner, M. F.; Gilless, J. K.

2017-12-01

California agriculture is an important economic activity for the state. California leads the nation in farms sales since 1950. In addition, agricultural employment in California reached approximately 410,000. Production of many fruits and vegetables is labor intensive and labor costs represent anywhere from 20% to 40% of total production costs. In additon, agricutlural production growth has been the highest for labor intensive crops such as berries (all types) and nuts. Given the importance of the agricultural sector and the labor component whithin it, the analysis of the impact of climate change on the agricultural sector of California becomes imperative. Heat waves are a weather related extreme that impact labor productivity, specially outdoor labor producitivity. We use crop production function analysis that incorporates socio economic variables such as crop prices, total acreage, production levels and harvest timiline with climate related variables such as an estimated Heat Index (HI) to analize the impact of heat waves on crop production via an impact on labor productivity for selected crops in the Central and Imperial Valleys in California. The analysis finds that the impact of heat waves varies by the degree of labor intensity of the crop and the relative intensity of the heat wave.

THERMAL POWER LOSS COMPENSATION IN THE PRODUCTION OF COOKED AND DRIED GRAINS WITH HEAT PUMPS USING

Directory of Open Access Journals (Sweden)

S. A. Shevtsov

2015-01-01

Full Text Available Using scientificand practical experience and analysis of recent innovative activity on modernization of food concentrates production, a new variant of the energy-efficient processing of cereal crops using superheated steam and direct involvement in the cooking and drying process waste energy using the vapor compression heat pump was suggested. A method for production of cereal concentrates, which is realized using microprocessor control of technological parameters. According to the information on the processes of cereals washing, cooking, drying and cooling microprocessor provides regime parameters control under the restrictions due to both yield of cooked and dried cereal of high quality and economic feasibility. At the same time the amount of moisture is continuously determined in the recirculation loop formed by the evaporation from the cereals in the drying process. To implement the proposed method of cooked and dried cereals production it is offered to use refrigerationand compressor unit operating in a heat pump mode. The refrigerant to be used is khladon 12V1 CF2ClBr with a boiling point in the evaporator of 4°C and the condensing temperature of 153.7 °C. The use of the heat pump in the heat supply system of cooked and dried cereals production instead of electric heaters will reduce power costs by 1.72 times. The proposed method for the production and control of technological parameters in the field of the product acceptable technological properties will provide high quality cooked and dried cereals; an increase in thermal efficiency by making full use of the waste heat of superheated steam; the reduction of specific energy consumption by 25-30 %; the creation of waste-free and environmentally friendly technologies for cereal production.

Convolution quotients in the production of heat in an infinite cylinder

Energy Technology Data Exchange (ETDEWEB)

Battig, A; Kalla, S L [Universidad Nacional de Tucuman (Argentina). Facultad de Ciencias Exactas y Tecnologia

1974-12-01

A solution of the problem of heat production in an infinite cylinder is considered by an appeal to the concept of convolution quotients and finite Hankel transforms. The result given by Erdelyi follows as a particular case of the result established here.

Heat production and storage are positively correlated with measures of body size/composition and heart rate drift during vigorous running.

Science.gov (United States)

Buresh, Robert; Berg, Kris; Noble, John

2005-09-01

The purposes of this study were to determine the relationships between: (a) measures of body size/composition and heat production/storage, and (b) heat production/storage and heart rate (HR) drift during running at 95% of the velocity that elicited lactate threshold, which was determined for 20 healthy recreational male runners. Subsequently, changes in skin and tympanic temperatures associated with a vigorous 20-min run, HR, and VO2 data were recorded. It was found that heat production was significantly correlated with body mass (r = .687), lean mass (r = .749), and body surface area (BSA, r = .699). Heat storage was significantly correlated with body mass (r = .519), fat mass (r = .464), and BSA (r = .498). The percentage of produced heat stored was significantly correlated with body mass (r = .427), fat mass (r = .455), and BSA (r = .414). Regression analysis showed that the sum of body mass, percentage of body fat, BSA, lean mass, and fat mass accounted for 30% of the variability in heat storage. It was also found that HR drift was significantly correlated with heat storage (r = .383), percentage of produced heat stored (r = .433), and core temperature change (r = .450). It was concluded that heavier runners experienced greater heat production, heat storage, and core temperature increases than lighter runners during vigorous running.

Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India.

Science.gov (United States)

Krishnamurthy, Manikandan; Ramalingam, Paramesh; Perumal, Kumaravel; Kamalakannan, Latha Perumal; Chinnadurai, Jeremiah; Shanmugam, Rekha; Srinivasan, Krishnan; Venugopal, Vidhya

2017-03-01

Workers laboring in steel industries in tropical settings with high ambient temperatures are subjected to thermally stressful environments that can create well-known risks of heat-related illnesses and limit workers' productivity. A cross-sectional study undertaken in a steel industry in a city nicknamed "Steel City" in Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration from urine color and urine specific gravity. A structured questionnaire captured self-reported heat-related health symptoms of workers. Some 90% WBGT measurements were higher than recommended threshold limit values (27.2-41.7°C) for heavy and moderate workloads and radiational heat from processes were very high in blooming-mill/coke-oven (67.6°C globe temperature). Widespread heat-related health concerns were prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures (χ 2  = 26.1258, degrees of freedom = 1, p  industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

The effect of load factor on fission product decay heat from discharged reactor fuel

International Nuclear Information System (INIS)

Davies, B.S.J.

1978-07-01

A sum-of-exponentials expression representing the decay heat power following a burst thermal irradiation of 235 U has been used to investigate the effect of load factor during irradiation on subsequent decay heat production. A sequence of random numbers was used to indicate reactor 'on' and 'off' periods for irradiations which continued for a total of 1500 days at power and were followed by 100 days cooling. It was found that for these conditions decay heat is almost proportional to load factor. Estimates of decay heat uncertainty arising from the random irradiation pattern are also given. (author)

Magnetic nanowires and hyperthermia: How geometry and material affect heat production efficiency

KAUST Repository

Contreras, Maria F.; Zaher, A.; Perez, Jose E.; Ravasi, Timothy; Kosel, Jü rgen

2015-01-01

Magnetic hyperthermia, which refers to the production of heat by magnetic nanostructures under an alternating magnetic field (AMF), has been previously investigated with superparamagnetic nanobeads as a cancer therapy method. Magnetic nanowires (NWs

The effect of intermittent lighting on metabolizable energy intake and heat production of male broilers.

Science.gov (United States)

Ohtani, S; Leeson, S

2000-02-01

Experiments were conducted to compare the effects of an intermittent lighting (IL) schedule with repeated cycles of 1 h light and 2 h darkness with a continuous lighting (CL) schedule on the performance, ME intake, and heat production of male broiler chickens. Body weight gain and feed intake were temporarily reduced after the changing from CL to IL; however, they were significantly higher in IL vs CL chickens during the subsequent period of 3 to 6 wk of age. The IL chickens exhibited a higher ME intake at 6 and 8 wk of age than did CL chickens. Total heat production in IL chickens was higher than for CL chickens, although heat production during the dark period was less than that during the light period for IL chickens. The higher feed intake observed in IL chickens appears to explain the superior body weight gain in IL broilers in simple terms.

Preliminary study concerning the influence of combined heat and radiation treatment on the quality of some horticultural products

International Nuclear Information System (INIS)

Langerak, D.Is.; Bruurs, M.F.J.

1973-01-01

In collaboration with a canning factory a number of horticultural products were preserved by means of the combined irradiation and heating treatment. The aim was to study the influence of the parameters irradiation and heat on quality and microbiological spoilage. The products were exposed to gamma-rays with doses varying from 0 to 1 Mrad. The heat treatment varied from 5 to 40 minutes at 98 to 121 0 C; time and temperature depended on the type of product. The sterilization value (F value) was measured by means of the method of Esty and Meyer for products with pH>5. The canned products were stored afterwards at 20-55 0 C. The organoleptic test showed that the colour and texture of most products were improved by the combined treatment, provided the irradiation dose did not exceed 0.25 Mrad. Strawberries in syrup discoloured at 0.1 Mrad. For a number of products the improved colour was partially lost during storage. Flavour and taste were not generally influenced unfavourably at doses up to 0.3 Mrad (exception: strawberries). The treatment sequence did not affect distinctly the quality or microbiological spoilage. The sterilization time (F value) of the combined treatment was determined by the shortest heating period required for the tenderness of the product. (F.J.)

Hydrogen production from coal using a nuclear heat source

International Nuclear Information System (INIS)

Quade, R.N.

1977-01-01

A strong candidate for hydrogen production in the intermediate time frame of 1990 to 1995 is a coal-based process using a high-temperature gas-cooled reactor (HTGR) as a heat source. Expected process efficiencies in the range of 60 to 70% are considerably higher than all other hydrogen production processes except steam reforming of a natural gas - a feedstock which may not be available in large quantities in this time frame. The process involves the preparation of a coal liquid, hydrogasification of that liquid, and steam reforming of the resulting gaseous or light liquid product. Bench-scale experimental work on the hydrogasification of coal liquids is being carried out. A study showing process efficiency and cost of hydrogen vs nuclear reactor core outlet temperature has been completed and shows diminishing returns at process temperatures above about 1500 0 F. (author)

Hydrogen production from coal using a nuclear heat source

Science.gov (United States)

Quade, R. N.

1976-01-01

A strong candidate for hydrogen production in the intermediate time frame of 1985 to 1995 is a coal-based process using a high-temperature gas-cooled reactor (HTGR) as a heat source. Expected process efficiencies in the range of 60 to 70% are considerably higher than all other hydrogen production processes except steam reforming of a natural gas. The process involves the preparation of a coal liquid, hydrogasification of that liquid, and steam reforming of the resulting gaseous or light liquid product. A study showing process efficiency and cost of hydrogen vs nuclear reactor core outlet temperature has been completed, and shows diminishing returns at process temperatures above about 1500 F. A possible scenario combining the relatively abundant and low-cost Western coal deposits with the Gulf Coast hydrogen users is presented which provides high-energy density transportation utilizing coal liquids and uranium.

Effects of Heat Stress on Construction Labor Productivity in Hong Kong: A Case Study of Rebar Workers.

Science.gov (United States)

Yi, Wen; Chan, Albert P C

2017-09-12

Global warming is bringing more frequent and severe heat waves, and the result will be serious for vulnerable populations such as construction workers. Excessive heat stress has profound effects on physiological responses, which cause occupational injuries, fatalities and low productivity. Construction workers are particularly affected by heat stress, because of the body heat production caused by physically demanding tasks, and hot and humid working conditions. Field studies were conducted between August and September 2016 at two construction training grounds in Hong Kong. Onsite wet-bulb globe temperature (WBGT), workers' heart rate (HR), and labor productivity were measured and monitored. Based on the 378 data sets of synchronized environmental, physiological, construction labor productivity (CLP), and personal variables, a CLP-heat stress model was established. It was found that WBGT, percentage of maximum HR, age, work duration, and alcohol drinking habits were determining factors for predicting the CLP (adjusted R ² = 0.68, p stress reduces CLP, with the percentage of direct work time decreasing by 0.33% when the WBGT increased by 1 °C. The findings in this study extend the existing practice notes by providing scientific data that may be of benefit to the industry in producing solid guidelines for working in hot weather.

Effects of heat on meat proteins - Implications on structure and quality of meat products.

Science.gov (United States)

Tornberg, E

2005-07-01

Globular and fibrous proteins are compared with regard to structural behaviour on heating, where the former expands and the latter contracts. The meat protein composition and structure is briefly described. The behaviour of the different meat proteins on heating is discussed. Most of the sarcoplasmic proteins aggregate between 40 and 60 °C, but for some of them the coagulation can extend up to 90°C. For myofibrillar proteins in solution unfolding starts at 30-32°C, followed by protein-protein association at 36-40°C and subsequent gelation at 45-50°C (conc.>0.5% by weight). At temperatures between 53 and 63°C the collagen denaturation occurs, followed by collagen fibre shrinkage. If the collagen fibres are not stabilised by heat-resistant intermolecular bonds, it dissolves and forms gelatine on further heating. The structural changes on cooking in whole meat and comminuted meat products, and the alterations in water-holding and texture of the meat product that it leads to, are then discussed.

Alteration of fasting heat production during fescue toxicosis in Holstein steers

Science.gov (United States)

This study was designed to examine alteration of fasting heat production (FHP) during fescue toxicosis. Six ruminally cannulated Holstein steers (BW=348 ±13 kg) were weight-matched into pairs and utilized in a two period crossover design experiment. Each period consisted of two temperature segments,...

Determining the effects of early gestation in utero heat stress on postnatal fasting heat production and circulating biomarkers associated with metabolism in growing pigs

Science.gov (United States)

The study objective was to determine the effects of in utero heat stress (IUHS) on postnatal fasting heat production (FHP) in growing pigs. Based on our previous observation of increased postnatal core body temperature ‘set-point’ in IUHS pigs, we hypothesized that FHP would be greater during postna...

Analysis of Competitiveness and Support Instruments for Heat and Electricity Production from Wood Biomass in Latvia

Science.gov (United States)

Klavs, G.; Kudrenickis, I.; Kundzina, A.

2012-01-01

Utilisation of renewable energy sources is one of the key factors in a search for efficient ways of reducing the emissions of greenhouse gases and improving the energy supply security. So far, the district heating supply in Latvia has been based on natural gas, with the wood fuel playing a minor role; the same is true for decentralised combined heat-power (CHP) production. The paper describes a method for evaluation of the economic feasibility of heat and electricity production from wood biomass under the competition between different fuel types and taking into account the electricity market. For the simulation, a cost estimation model is applied. The results demonstrate that wood biomass can successfully be utilised for competitive heat production by boiler houses, while for electricity production by CHP utilities it cannot compete on the market (even despite the low prices on wood biomass fuel) unless particular financial support instruments are applied. The authors evaluate the necessary support level and the impact of two main support instruments - the investment subsidies and the feed-in tariff - on the economic viability of wood-fuelled CHP plants, and show that the feed-in tariff could be considered as an instrument strongly affecting the competitiveness of such type CHP. Regarding the feed-in tariff determination, a compromise should be found between the economy-dictated requirement to develop CHP projects concerning capacities above 5 MWel - on the one hand, and the relatively small heat loads in many Latvian towns - on the other.

Effects of heating rate on slow pyrolysis behavior, kinetic parameters and products properties of moso bamboo.

Science.gov (United States)

Chen, Dengyu; Zhou, Jianbin; Zhang, Qisheng

2014-10-01

Effects of heating rate on slow pyrolysis behaviors, kinetic parameters, and products properties of moso bamboo were investigated in this study. Pyrolysis experiments were performed up to 700 °C at heating rates of 5, 10, 20, and 30 °C/min using thermogravimetric analysis (TGA) and a lab-scale fixed bed pyrolysis reactor. The results show that the onset and offset temperatures of the main devolatilization stage of thermogravimetry/derivative thermogravimetry (TG/DTG) curves obviously shift toward the high-temperature range, and the activation energy values increase with increasing heating rate. The heating rate has different effects on the pyrolysis products properties, including biochar (element content, proximate analysis, specific surface area, heating value), bio-oil (water content, chemical composition), and non-condensable gas. The solid yields from the fixed bed pyrolysis reactor are noticeably different from those of TGA mainly because the thermal hysteresis of the sample in the fixed bed pyrolysis reactor is more thorough. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magnetic nanowires and hyperthermia: How geometry and material affect heat production efficiency

KAUST Repository

Contreras, Maria F.

2015-05-01

Magnetic hyperthermia, which refers to the production of heat by magnetic nanostructures under an alternating magnetic field (AMF), has been previously investigated with superparamagnetic nanobeads as a cancer therapy method. Magnetic nanowires (NWs) used in hyperthermia can be very promising, as it has been shown that they have a larger magnetic moment per unit of volume compared to the nanobeads. Moreover, Fe NWs proved to have a higher heating efficiency compared to Fe nanobeads, when exposed to an AMF at the same concentration [1].

Theoretical Design of a Thermosyphon for Efficient Process Heat Removal from Next Generation Nuclear Plant (NGNP) for Production of Hydrogen

International Nuclear Information System (INIS)

Piyush Sabharwall; Fred Gunnerson; Akira Tokuhiro; Vivek Utgiker; Kevan Weaver; Steven Sherman

2007-01-01

The work reported here is the preliminary analysis of two-phase Thermosyphon heat transfer performance with various alkali metals. Thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. Heat transport occurs via evaporation and condensation, and the heat transport fluid is re-circulated by gravitational force. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. For process heat, intermediate heat exchangers (IHX) are required to transfer heat from the NGNP to the hydrogen plant in the most efficient way possible. The production of power at higher efficiency using Brayton Cycle, and hydrogen production requires both heat at higher temperatures (up to 1000 C) and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. The purpose for selecting a compact heat exchanger is to maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. The IHX design requirements are governed by the allowable temperature drop between the outlet of the NGNP (900 C, based on the current capabilities of NGNP), and the temperatures in the hydrogen production plant. Spiral Heat Exchangers (SHE's) have superior heat transfer characteristics, and are less susceptible to fouling. Further, heat losses to surroundings are minimized because of its compact configuration. SHEs have never been examined for phase-change heat transfer applications. The research presented provides useful information for thermosyphon design and Spiral Heat Exchanger

District heating for increased biogas production. Technical and economical evaluation of district heating as heating source in biogas processes; Fjaerrvaerme foer utoekad biogasproduktion. Teknisk och ekonomisk utvaerdering av fjaerrvaerme foer uppvaermning av biogasprocesser

Energy Technology Data Exchange (ETDEWEB)

Lundqvist, Per (AaF-Consult AB, Stockholm (Sweden))

2009-11-15

This report presents a technical evaluation, the potential and an economical evaluation of the increased net biogas production by using district heating as energy supply for different types of biogas production units. The study presents generalized results for different plant sizes. The district heating is considered as replacement of the heat produced by burning biogas in a hot-water boiler. Hence more biogas could be available for upgrading to fuel-gas quality to be used in vehicles as a renewable fuel. The study is aimed at biogas producers, district heating and combined heat and power (CHP) companies. Biogas has a composition of mostly methane (about 65 %) and carbon dioxide (about 35 %) and small amounts of other gases e.g. sulphur dioxide (H{sub 2}S). Biogas up-grading is a process where the methane content is increased to about 97 % by removing most of the other gases in e.g. an absorption unit. The Swedish biogas is mainly produced in several sewage treatment plants and some co-digestion units but is also collected from dumps. Biogas is produced by anaerobic microorganisms at temperatures of about 36 and 55 deg C which correspond to the thermal optimum for mesophile and thermophile bacteria respectively. Co-digestion of animal material which e.g. is contained in collected organic household waste has to be pasteurized at 70 deg C for 1h according to EU-regulations. Such regulations may also be introduced to the sludge from municipal sewage treatment plants. Due to the fact that the process temperature is higher than the temperature of the substrate (sludge or organic waste material) as well as the outdoor temperature, both heating of the incoming substrate and compensation of heat losses are required. Traditionally most of the biogas has been burnt to generate the necessary heat for the process and premises at the plant. The excess gas has been burnt in a torch. In recent years the biogas produced in Sweden has found increased use as a renewable vehicle fuel

High temperature reactor for the production of low temperature heat

International Nuclear Information System (INIS)

Muehlensiep, J.

1986-12-01

In this report the conditions of nuclear working reactors for district heating are described for the use in suburban areas. The design of a HTR is analysed under the point of view of safety and costs for the components and for the arrangement possibilities. The size of system is chosen by analysing important parameters for construction. The layout is determined by the retention of fission products in the coated particles of the fuel under conditions of hypothetical accidents. Based on stated data a HTR reactor for district heating will be designed. The speciality is a square shaped core which has the advantage to conduct the afterheat fastly to the outside of the pressure vessel in case of hypothetical accidents. Caused by the shape of the core the heat exchangers may be installed next to the core, the shutdown rods are maintained into reflector borings where they have a high efficiency. The whole primary circuit is surrounded by the reactor pressure vessel and is adjusted in an underground concrete cell. (orig./GL) [de

Environmental and energy efficiency evaluation of residential gas and heat pump heating

International Nuclear Information System (INIS)

Ganji, A.R.

1993-01-01

Energy efficiency and source air pollutant emission factors of gas heaters, gas engine heat pumps, and electric heat pumps for domestic heating have been evaluated and compared. The analysis shows that with the present state of technology, gas engine heat pumps have the highest energy efficiency followed by electric heat pumps and then gas heaters. Electric heat pumps produce more than twice as much NO x , and comparable CO 2 and CO per unit of useful heating energy compared to natural gas heaters. CO production per unit of useful heating energy from gas engine heat pumps without any emission control is substantially higher than electric heat pumps and natural gas heaters. NO x production per unit of useful heating energy from natural gas engine heat pumps (using lean burn technology) without any emission control is about the same as effective NO x production from electric heat pumps. Gas engine heat pumps produce about one-half CO 2 compared to electric heat pumps

Life Cycle Assessment of Miscanthus as a Fuel Alternative in District Heat Production

DEFF Research Database (Denmark)

Parajuli, Ranjan; Dalgaard, Tommy; Nguyen, Thu Lan Thi

2013-01-01

better than in the boilerfrom the stand point of GWP and savings in fossil fuels, but leads to a higher LU.A comparison between Miscanthus and NG shows that the former in spite of possessing advantage in reducing GWP and NRE use,additional land required for it could be seen as a disadvantage. Key words......This study assesses the environmental performance of district heat production based on Miscanthus as a fuel input and compares it with Natural Gas (NG). As a baseline scenario, we assume that the process of energy conversion from Miscanthus to heat takes place in a Combined Heat and Power (CHP...

Effect of Discrete Fracture Network Characteristics on the Sustainability of Heat Production in Enhanced Geothermal Reservoirs

Science.gov (United States)

Riahi, A.; Damjanac, B.

2013-12-01

Viability of an enhanced or engineered geothermal reservoir is determined by the rate of produced fluid at production wells and the rate of temperature drawdown in the reservoir as well as that of the produced fluid. Meeting required targets demands sufficient permeability and flow circulation in a relatively large volume of rock mass. In-situ conditions such overall permeability of the bedrock formation, magnitude and orientation of stresses, and the characteristics of the existing Discrete Fracture Network (DFN) greatly affect sustainable heat production. Because much of the EGS resources are in formations with low permeability, different stimulation techniques are required prior to the production phase to enhance fluid circulation. Shear stimulation or hydro-shearing is the method of injecting a fluid into the reservoir with the aim of increasing the fluid pressure in the naturally fractured rock and inducing shear failure or slip events. This mechanism can enhance the system's permeability through permanent dilatational opening of the sheared fractures. Using a computational modeling approach, the correlation between heat production and DFN statistical characteristics, namely the fracture length distribution, fracture orientation, and also fracture density is studied in this paper. Numerical analyses were completed using two-dimensional distinct element code UDEC (Itasca, 2011), which represents rock masses as an assembly of interacting blocks separated by fractures. UDEC allows for simulation of fracture propagation along the predefined planes only (i.e., the trajectory of the hydraulic fracture is not part of the solution of the problem). Thus, the hydraulic fracture is assumed to be planar, aligned with the direction of the major principal stress. The pre-existing fractures were represented explicitly. They are discontinuities which deform elastically, but also can open and slip (Coulomb slip law) as a function of pressure and total stress changes. The fluid

Soil heating in connection with outdoor garden production. Maan laemmittaeminen avomaan puutarhatuotannossa

Energy Technology Data Exchange (ETDEWEB)

Malkki, S.; Moilanen, J.

1991-01-01

Soil heating using electricity, hot water and air has been studied within Nordic countries as a way to extend the growing season in spring. The methods have not found general acceptance in practical outdoor garden production in Nordic countries, except in Iceland. The main reason for this may be the fairly high investment costs, lack of know-how, and the above-normal risks both at the cultivation stage and in marketing of the harvest. Two thirds of the respondents (177 persons) were prepared to accept the soil heating on outdoor garden production by electrical cables if it is profitable. Only one fifth of the respondents thought that it would be wasting of natural resources, and that plant protection by chemicals should be cut down in the future or to keep their use at the present level. The respondents believed that more efforts should be made in marketing of the garden products by improving the product quality, purity and aroma, because these are the most important sales promotion factors. Two thirds thought that the Finnish garden production sector would retain it's present status or improve it in the future. Organic farming and greening were believed to possess the best prerequisites for surviving the increasingly tough competition of the non-restricted European markets. Under-glass cultivation and fruit orchards in Finland were believed to run into difficulties.

Conception of a heat storage system for household applications. Category: New product innovations

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Thomas [Leuphana Univ. Lueneburg (Germany); Rammelberg, Holger U.; Roennebeck, Thomas [and others

2012-07-01

Almost 90% of the energy consumption of private households in Germany is used for heating. Thus, an efficient, sustainable and reliable heat management is one of the main challenges in the future. Heat storage will become a key technology when considering the daily, weekly, seasonal and unpredictable fluctuations of energy production with renewables. The storage of heat is much more volume- and energy-efficient as well as more economical than electricity storage. However, transport of heat over long distances is coupled with high losses, compared with electricity transport. Therefore, we propose the use of micro CHP in combination with volume-efficient and nearly loss-free heat storage to counteract electricity fluctuations. Focus of this contribution the conception of the large-scale project ''Thermal Battery'', funded by the European Union and the Federal State of Lower Saxony. The underlying principle is the utilization of reversible thermochemical reactions, such as dehydration and rehydration of salt hydrates for heat storage. The main goal is the development of a prototypical storage tank, which is capable of storing 80 kWh of heat with a system volume of less than 1 m{sup 3}. Importantly, the Vattenfall New Energy Services as a collaboration partner will support the development of an application-oriented heat storage device. This project is being carried out by an interdisciplinary team of engineers, chemists, physicists and environmental scientists.

Nuclear heat for industrial purposes and district heating

International Nuclear Information System (INIS)

1974-01-01

Studies on the various possibilities for the application of heat from nuclear reactors in the form of district heat or process steam for industrial purposes had been made long before the present energy crisis. Although these studies have indicated technical feasibility and economical justification of such utilization, the availability of relatively cheap oil and difficulties in locating a nuclear heat source inside industrial areas did not stimulate much further development. Since the increase of oil prices, the interest in nuclear heat application is reawakened, and a number of new potential areas have been identified. It now seems generally recognized that the heat from nuclear reactors should play an important role in primary energy supply, not only for electricity production but also as direct heat. At present three broad areas of nuclear heat application are identified: Direct heat utilization in industrial processing requiring a temperature above 800 deg. C; Process steam utilization in various industries, requiring a temperature mainly in the range of 200-300 deg. C; Low temperature and waste heat utilization from nuclear power plants for desalination of sea water and district heating. Such classification is mainly related to the type and characteristics of the heat source or nuclear reactor which could be used for a particular application. Modified high temperature reactor types (HTR) are the candidates for direct heat application, while the LWR reactors can satisfy most of the demands for process steam. Production of waste heat is a characteristic of all thermal power plants, and its utilization is a major challenge in the field of power production

Cooling and heating in modern wine production; Kjoeling og oppvarming i moderne vinproduksjon

Energy Technology Data Exchange (ETDEWEB)

Merati, Renato Giovanni; Triacca, Domenica

2009-07-01

The production of wine increases worldwide. Research on technologies to achieve better quality goes on continuously. The most advanced technologies are cooling and heating systems which produces wines of higher qualities. (AG)

Estimation of heat transfer and heat source in a molten pool

Energy Technology Data Exchange (ETDEWEB)

Yun, J.I.; Suh, K.Y.; Kang, C.S. [Seoul National Univ., Dept. of Nuclear Engineering (Korea, Republic of)

2001-07-01

Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the pool. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool was estimated by product of the mass concentration and energy conversion factor of each fission product. For the calculation of heat generation rate in the pool, twenty-nine (29) elements were chosen and classified by their chemical properties. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis was performed for the TMI-2 accident. The pool is assumed to be a partially filled hemispherical geometry, 1.45 m in radius and 32,700 kg in mass. The change of pool geometry during the numerical calculation was neglected. The peak temperature sizably decreased by about 60 K as the fission products were released from the pool. (author)

Estimation of heat transfer and heat source in a molten pool

International Nuclear Information System (INIS)

Yun, J.I.; Suh, K.Y.; Kang, C.S.

2001-01-01

Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the pool. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool was estimated by product of the mass concentration and energy conversion factor of each fission product. For the calculation of heat generation rate in the pool, twenty-nine (29) elements were chosen and classified by their chemical properties. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis was performed for the TMI-2 accident. The pool is assumed to be a partially filled hemispherical geometry, 1.45 m in radius and 32,700 kg in mass. The change of pool geometry during the numerical calculation was neglected. The peak temperature sizably decreased by about 60 K as the fission products were released from the pool. (author)

Safety aspects of targets for ADTT: Activity, volatile products, residual heat release

International Nuclear Information System (INIS)

Gai, E.V.; Ignatyuk, A.V.; Lunev, V.P.; Shubin, Yu.N.

1999-01-01

Safety aspects of heavy metal liquid targets for the accelerator driven systems connected with the activity accumulation and residual energy release due to the irradiation with high energy proton beam are discussed. The results obtained for the lead-bismuth target that are under construction in IPPE now in the frame of ISTC Project No. 559 are briefly presented. The calculations and the analysis of the accumulation of the spallation reaction products, activity and energy release at various moments after the accelerator shutdown are presented. The concentrations of the reaction products, the total and partial activities, the activities of volatile products are determined. The contributions of the short-lived nuclides important for the prediction of the facility behaviour in regimes with the accelerator beam trips. The calculations and analysis of the residual energy release due to different decay type have been performed. The conclusions are as follows. The obtained results showed that long lived radioactivity accumulates mainly due to primary nuclear reactions. Secondary reactions are responsible for the production of small number of long-lived isotopes Bi-207, Po-210 and some others, being generated by radiative capture of low energy neutrons. It is possible to make a conclusion that neutrons in the energy range 20 - 800 MeV and protons with energy above 100 MeV give main contribution to the total activity generation although these parts of spectra inside the target give comparatively small contribution to the total flux. The correct consideration of short-lived nuclides contribution is the main problem in the analysis of the target behaviour in the case of short accelerator shutdowns. They make the determining contribution to the both activity and the heat release at the first moments after the accelerator shutdown, creating the intermediate links and additional channels for the long-lived nuclides accumulation chains. The strong dependence of calculated

Experimental investigation of molten salt droplet quenching and solidification processes of heat recovery in thermochemical hydrogen production

International Nuclear Information System (INIS)

Ghandehariun, S.; Wang, Z.; Naterer, G.F.; Rosen, M.A.

2015-01-01

Highlights: • Thermal efficiency of a thermochemical cycle of hydrogen production is improved. • Direct contact heat recovery from molten salt is analyzed. • Falling droplets quenched into water are investigated experimentally. - Abstract: This paper investigates the heat transfer and X-ray diffraction patterns of solidified molten salt droplets in heat recovery processes of a thermochemical Cu–Cl cycle of hydrogen production. It is essential to recover the heat of the molten salt to enhance the overall thermal efficiency of the copper–chlorine cycle. A major portion of heat recovery within the cycle can be achieved by cooling and solidifying the molten salt exiting an oxygen reactor. Heat recovery from the molten salt is achieved by dispersing the molten stream into droplets. In this paper, an analytical study and experimental investigation of the thermal phenomena of a falling droplet quenched into water is presented, involving the droplet surface temperature during descent and resulting composition change in the quench process. The results show that it is feasible to quench the molten salt droplets for an efficient heat recovery process without introducing any material imbalance for the overall cycle integration.

Detection of heat wave using Kalpana-1 VHRR land surface temperature product over India

Science.gov (United States)

Shah, Dhiraj; Pandya, Mehul R.; Pathak, Vishal N.; Darji, Nikunj P.; Trivedi, Himanshu J.

2016-05-01

Heat Waves can have notable impacts on human mortality, ecosystem, economics and energy supply. The effect of heat wave is much more intense during summer than the other seasons. During the period of April to June, spells of very hot weather occur over certain regions of India and global warming scenario may result in further increases of such temperature anomalies and corresponding heat waves conditions. In this paper, satellite observations have been used to detect the heat wave conditions prevailing over India for the period of May-June 2015. The Kalpana-1 VHRR derived land surface temperature (LST) products have been used in the analysis to detect the heat wave affected regions over India. Results from the analysis shows the detection of heat wave affected pixels over Indian land mass. It can be seen that during the study period the parts of the west India, Indo-gangetic plane, Telangana and part of Vidarbh was under severe heat wave conditions which is also confirmed with Automatic Weather Station (AWS) air temperature observations.

A high temperature heating device for the study of fission product release from nuclear fuel

International Nuclear Information System (INIS)

Svedkauskaite-Le Gore, Jolanta; Kivel, Niko; Guenther-Leopold, Ines

2010-01-01

At the Paul Scherrer Institute a high temperature inductive heating furnace, which can heat fuel samples up to 2300 deg. C, has been developed in order to study the release of fission products. The furnace can be directly connected to an inductively coupled plasma mass spectrometer for online monitoring of the released elements and does not require their trapping before measurement. This paper describes the design of the inductive heating furnace, discusses its operating parameters, limitations and illustrates foreseen applications. (authors)

ASSESSMENT OF THE MOISTURE EFFECT ON GASEOUS PRODUCTS OF SELF-HEATING OF WOOD CHIPS

Directory of Open Access Journals (Sweden)

Hana VĚŽNÍKOVÁ

2017-12-01

Full Text Available Biofuels are stored in large quantities and may be susceptible to self-ignition. The possible methods of indication of temperature increase include the analysis of the gaseous products of heating where concentrations of certain gases may increase with increasing temperature. Gas release is also affected by the moisture of the material given that the moisture level changes surface accessibility for oxygen on the one side and serves as a catalyst of the oxidation reactions on the other. The present project analysed the effect of temperature and moisture on gaseous products of heating of wood chips, one of frequently used biofuels, with the aim to determine a suitable gaseous indicator of beginning self-ignition.

Transportation fuel production from gasified biomass integrated with a pulp and paper mill – Part A: Heat integration and system performance

International Nuclear Information System (INIS)

Isaksson, Johan; Jansson, Mikael; Åsblad, Anders; Berntsson, Thore

2016-01-01

Production of transportation fuels from biorefineries via biomass gasification has been suggested as a way of introducing renewable alternatives in the transportation system with an aim to reduce greenhouse gas emissions to the atmosphere. By co-locating gasification-based processes within heat demanding industries, excess heat from the gasification process can replace fossil or renewable fuels. The objective of this study was to compare the heat integration potential of four different gasification-based biorefinery concepts with a chemical pulp and paper mill. The results showed that the choice of end-product which was either methanol, Fischer-Tropsch crude, synthetic natural gas or electricity, can have significant impact on the heat integration potential with a pulp and paper mill and that the heat saving measures implemented in the mill in connection to integration of a gasification process can increase the biomass resource efficiency by up to 3%-points. Heat saving measures can reduce the necessary biomass input to the biorefinery by 50% if the sizing constraint is to replace the bark boiler with excess heat from the biorefinery. A large integrated gasification process with excess steam utilisation in a condensing turbine was beneficial only if grid electricity is produced at below 30% electrical efficiency. - Highlights: • Biomass gasification integrated with a pulp and paper mill. • Different sizing constraints of integrated biofuel production. • The biofuel product largely influence the heat integration potential. • An oversized gasifier for increased power production could be favourable.

Dietary fat affects heat production and other variables of equine performance, under hot and humid conditions.

Science.gov (United States)

Kronfeld, D S

1996-07-01

Does dietary fat supplementation during conditioning improve athletic performance, especially in the heat? Fat adaptation has been used to increase energy density, decrease bowel bulk and faecal output and reduce health risks associated with hydrolysable carbohydrate overload. It may also reduce spontaneous activity and reactivity (excitability), increase fatty acid oxidation, reduce CO2 production and associated acidosis, enhance metabolic regulation of glycolysis, improve both aerobic and anaerobic performance and substantially reduce heat production. A thermochemical analysis of ATP generation showed the least heat release during the direct oxidation of long chain fatty acids, which have a 3% advantage over glucose and 20 to 30% over short chain fatty acids and amino acids. Indirect oxidation via storage as triglyceride increased heat loss during ATP generation by 3% for stearic acid, 65% for glucose and 174% for acetic acid. Meal feeding and nutrient storage, therefore, accentuates the advantage of dietary fat. A calorimetric model was based on initial estimates of net energy for competitive work (10.76 MJ for the Endurance Test of an Olympic level 3-day-event), other work (14.4 MJ/day) and maintenance (36 MJ), then applied estimates of efficiencies to derive associated heat productions for the utilisation of 3 diets, Diet A: hay (100), Diet B: hay and oats (50:50) and Diet C: hay, oats and vegetable oil (45:45:10), the difference between the last 2 diets representing fat adaptation. During a 90.5 min speed and stamina test, heat production was estimated as 37, 35.4 and 34.6 MJ for the 3 diets, respectively, an advantage 0.8 MJ less heat load for the fat adapted horse, which would reduce water needed for evaporation by 0.33 kg and reduce body temperature increase by about 0.07 degree C. Total estimated daily heat production was 105, 93 and 88 MJ for the 3 diets, respectively, suggesting a 5 MJ advantage for the fat adapted horse (Diet C vs. Diet B). Estimated

Dynamic Heat Production Modeling for Life Cycle Assessment of Insulation in Danish Residential Buildings

DEFF Research Database (Denmark)

Sohn, Joshua L.; Kalbar, Pradip; Birkved, Morten

2017-01-01

insulation in a Danish single-family detached home. This single family house, is based on averages of current Danish construction practices with building heat losses estimated using Be10. To simulate a changing district heating grid mix, heat supply fuel sources are modeled according to Danish energy mix...... for space heating without insulation over the lifespan of a building. When the energy sources for insulation production are similar to the energy mix that supplies heat, this logic is valid to very high level of insulation. However, in Denmark, as well as many other countries this assumption is becoming...... increasingly incorrect. Given the generally long service life of buildings, the significance of future energy mixes, which are expected/intended to have a smaller environmental impact, can be great. In this paper, a reference house is used to assess the life cycle environmental impacts of mineral wool...

Determination of heat production zones at open-cast mine dump

International Nuclear Information System (INIS)

Schreck, M.; Nishigaki, M.; Glaser, H.R.; Christoph, G.; Grosswig, S.; Hurtig, E.; Kasch, M.; Kuhn, K.

1998-01-01

The chemical processes and their thermal effects taking place inside a dump of an open-cast mine (Cospuden) during a reclamation process were investigated. Fiber-optic-distributed-temperature sensing (DTS) was applied together with a soil ground water monitoring system (SGM-System). An optical fiber was mounted at the entire length of a double-pipe SGM-System. The temperature was measured monthly, along the depth of 50 m, with a spatial resolution of 0.5 m. The system was utilized for the localization of heat production zones in the subsurface, for the determination of the temperature variation's penetration depth from the surface into the soil of the dump and for the determination of the influence of the SGM-System on the subsurface temperature balance. The results were compared with a heat transport model and then interpreted

Profitability of heating entrepreneurship from the viewpoint of heating energy buyer, heating energy seller and energy wood seller

Energy Technology Data Exchange (ETDEWEB)

Sauvula-Seppaelae, T.; Ulander, E. (Seinaejoki Univ. of Applied Sciences, Ahtari (Finland), School of Agriculture and Forestry), e-mail: tiina.sauvula-seppala@seamk.fi, e-mail: essi.ulander@seamk.fi

2010-07-01

The focus of this research was to study the profitability of heating entrepreneurships from the viewpoint of heating energy buyer, seller as well as energy wood seller. The average costs of heat production were Eur 44,8 / MWh and incomes Eur 43,4 /MWh. Energy wood purchase, comminution and long distance transportation formed slightly over a half of the heat production costs. Average net income in the group of the largest heating plants (>1000 kW) was Eur 29000 per year and in the group of the smallest (<200 kW) average net income was slightly over Eur 4000 per year. The net income from selling heat represents only a part of the income a heating entrepreneur receives from heat production. Other, significant parts are formed by income from selling energy wood to the plant as well as compensation for supervision and maintenance of the plant. The average net income of a forest owner from selling energy wood to heating entrepreneurs was Eur 18 / m3. Without state subsidies the net income would have been Eur 4 / m3. The price of the heating energy sold by heating entrepreneurs was very competitive. In 2006 it was Eur 30 / MWh cheaper than oil heat, Eur 34 / MWh cheaper than electric heat and Eur 3 / MWh cheaper than district heating. (orig.)

Heat pipe and method of production of a heat pipe

International Nuclear Information System (INIS)

Kemp, R.S.

1975-01-01

The heat pipe consists of a copper pipe in which a capillary network or wick of heat-conducting material is arranged in direct contact with the pipe along its whole length. Furthermore, the interior space of the tube contains an evaporable liquid for pipe transfer. If water is used, the capillary network consists of, e.g., a phosphorus band network. To avoid contamination of the interior of the heat pipe during sealing, its ends are closed by mechanical deformation so that an arched or plane surface is obtained which is in direct contact with the network. After evacuation of the interior space, the remaining opening is closed with a tapered pin. The ratio wall thickness/tube diameter is between 0.01 and 0.6. (TK/AK) [de

Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

Directory of Open Access Journals (Sweden)

M. R. Monazzam Esmaielpour

2015-09-01

Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. . Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. .Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. .Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is

Preliminary estimations on the heat recovery method for hydrogen production by the high temperature steam electrolysis

International Nuclear Information System (INIS)

Koh, Jae Hwa; Yoon, Duck Joo

2009-01-01

As a part of the project 'development of hydrogen production technologies by high temperature electrolysis using very high temperature reactor', we have developed an electrolyzer model for high temperature steam electrolysis (HTSE) system and carried out some preliminary estimations on the effects of heat recovery on the HTSE hydrogen production system. To produce massive hydrogen by using nuclear energy, the HTSE process is one of the promising technologies with sulfur-iodine and hybrid sulfur process. The HTSE produces hydrogen through electrochemical reaction within the solid oxide electrolysis cell (SOEC), which is a reverse reaction of solid oxide fuel cell (SOFC). The HTSE system generally operates in the temperature range of 700∼900 .deg. C. Advantages of HTSE hydrogen production are (a) clean hydrogen production from water without carbon oxide emission, (b) synergy effect due to using the current SOFC technology and (c) higher thermal efficiency of system when it is coupled nuclear reactor. Since the HTSE system operates over 700 .deg. C, the use of heat recovery is an important consideration for higher efficiency. In this paper, four different heat recovery configurations for the HTSE system have been investigated and estimated

Hydrogen production by water-splitting using heat supplied by a high-temperature reactor

International Nuclear Information System (INIS)

Courvoisier, P.; Rastoin, J.; Titiliette, Z.

1976-01-01

Some aspects of the use of heat of nuclear origin for the production of hydrogen by water-splitting are considered. General notions pertaining to the yield of chemical cycles are discussed and the heat balance corresponding to two specific processes is evaluated. The possibilities of high temperature reactors, with respect to the coolant temperature levels, are examined from the standpoint of core design and technology of some components. Furthermore, subject to a judicious selection of their characteristics, these reactors can lead to excellent use of nuclear fuel. The coupling of the nuclear reactor with the chemical plant by means of a secondary helium circuit gives rise to the design of an intermediate heat exchanger, which is an important component of the overall installation. (orig.) [de

Determination of thermal characteristics of combustion products of fire-tube heat generator with flow turbulator

Directory of Open Access Journals (Sweden)

Lukjanov Alexander V.

2014-12-01

Full Text Available Boiler construction is one of the major industries of any state. The aim is to determine the effect of the turbulator on the intensity of heat transfer in the convective part of the fire-tube heat generator of domestic production. The improvement of convective heating surfaces is one of the ways to increase the energy efficiency of the fire-tube heat generator. Since model of the process of heat transfer of gas flow in the convective tubes is multifactorial and does not have clear analytical solution at present, the study of process above is carried out using the experimental method. The results of applying the flow turbulator as a broken tape in the fire-tube heat generator of KV-GM type are presented. On their basis it can be concluded about increasing of heat transfer in convective part of the unit. The use of efficient, reliable, easy to manufacture, relatively inexpensive turbulator in domestic fire-tube heat generators will allow to increase their energy conversion efficiency and reduce fuel consumption, which will have a positive economic effect.

Viscose liquid heat treatment using plate scraper heat exchanger

Directory of Open Access Journals (Sweden)

K. A. Rashkin

2012-01-01

Full Text Available The current work analyzes the use of different types of heat exchangers, depending on the technology of production. It is taken the detail analysis of the ways of applicability of various types of heat exchangers, depending on the viscosity of the processed product. It is posed the problem of the analytical determination of the required area of heat exchange with the use of differential equations of heat transfer in a moving liquid media, written in cylindrical coordinates, for symmetrical temperature distribution, without taking in account the energy dissipation.

The way to bio heat. A manual on production of heat from bio fuel; Veien til biovarme. Manual for produksjon av ferdigvarme fra biobrensel

Energy Technology Data Exchange (ETDEWEB)

Breen, Tor; Liodden, Ole Joergen; Farsund Oeystein; Martinsen, Arnold Kyrre

2008-09-26

The manual is a tool in the process of planning and establishing a bio heat company. It focuses on both technical, administrative, and economic aspects. Part 1 of the manual briefly reviews the production of bio fuel and bio heat, part 2 considers the organizational aspects of the project, and part 3 is a tool box containing laws and regulations, templates for contracts/agreements etc

Geothermal heat - The second stream for geothermal sectors; Electricity production: industries are facing the geological unexpected events; Heat networks: a new boom in France

International Nuclear Information System (INIS)

Minster, Jean-Francois; Appert, Olivier; Moisant, Francois; Salha, Bernard; Tardieu, Bernard; Florette, Marc; Basilico, Laurent

2013-01-01

A first article proposes an overview of recent development in the field of geothermal power (individual heat pumps, urban heating networks, electricity production in volcanic context, and possibility of non conventional fields). These developments are notably interesting in a context of an evolving energy mix. Some benefits of geothermal power are outlined: a reliable and predictable production, and a low footprint. An installation of deep geothermal power in Alsace is presented. By evoking the construction of three high-energy geothermal power stations by GDF Suez in Sumatra, a second article outlines the high costs associated with exploration drilling which can face geological difficulties. It indicates and comments the distribution of costs among exploration, confirmation, authorizations, drilling, steam collection, electric plant, and connection to the grid. The third and last article comments the development of heat networks in France, and more particularly in the Parisian Basin which has the highest concentration of low-energy geothermal exploitations

An evaluation of neutron and gamme heating in fission product isotopes

International Nuclear Information System (INIS)

Leal, L.C.; Hill, R.N.; Khalil, H.S.

1993-01-01

The accurate prediction of the energy deposition rate in fast reactors, particularly in blanket and nonfueled regions, requires explicit treatment of gamma photon transport. Such an explicit treatment is part of the coupled neutron-photon heating method in use at Argonne National Laboratory, (ANL). In applying this procedure, three approximations are made in connection with the modeling of fission products (FPs): 1. The contribution of the FP neutron interactions to the gamma source is neglected. 2. In computing the macroscopic gamma interaction cross sections, the FPs are either neglected or simulated with an element (usually molybdenum) representative of an open-quotes averageclose quotes FP. 3. The heating contribution of the FP is neglected by use of zero FP kerma factors

An evaluation of nodalization/decay heat/ volatile fission product release models in ISAAC code

Energy Technology Data Exchange (ETDEWEB)

Song, Yong Mann; Park, Soo Yong; Kim, Dong Ha

2003-03-01

An ISAAC computer code, which was developed for a Level-2 PSA during 1995, has developed mainly with fundamental models for CANDU-specific severe accident progression and also the accident-analyzing experiences are limited to Level-2 PSA purposes. Hence the system nodalization model, decay model and volatile fission product release model, which are known to affect fission product behavior directly or indirectly, are evaluated to both enhance understanding for basic models and accumulate accident-analyzing experiences. As a research strategy, sensitivity studies of model parameters and sensitivity coefficients are performed. According to the results from core nodalization sensitivity study, an original 3x3 nodalization (per loop) method which groups horizontal fuel channels into 12 representative channels, is evaluated to be sufficient for an optimal scheme because detailed nodalization methods have no large effect on fuel thermal-hydraulic behavior, total accident progression and fission product behavior. As ANSI/ANS standard model for decay heat prediction after reactor trip has no needs for further model evaluation due to both wide application on accident analysis codes and good comparison results with the ORIGEN code, ISAAC calculational results of decay heat are used as they are. In addition, fission product revaporization in a containment which is caused by the embedded decay heat, is demonstrated. The results for the volatile fission product release model are analyzed. In case of early release, the IDCOR model with an in-vessel Te release option shows the most conservative results and for the late release case, NUREG-0772 model shows the most conservative results. Considering both early and late release, the IDCOR model with an in-vessel Te bound option shows mitigated conservative results.

Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources

International Nuclear Information System (INIS)

Harvego, Edwin A.; McKellar, Michael G.; O'Brien, James E.; Herring, J. Stephen

2009-01-01

High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 C to 950 C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered

Heat Stress

Science.gov (United States)

... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir OSHA-NIOSH ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...

Improving the thermal efficiency of a jaggery production module using a fire-tube heat exchanger.

Science.gov (United States)

La Madrid, Raul; Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel

2017-12-15

Jaggery is a product obtained after heating and evaporation processes have been applied to sugar cane juice via the addition of thermal energy, followed by the crystallisation process through mechanical agitation. At present, jaggery production uses furnaces and pans that are designed empirically based on trial and error procedures, which results in low ranges of thermal efficiency operation. To rectify these deficiencies, this study proposes the use of fire-tube pans to increase heat transfer from the flue gases to the sugar cane juice. With the aim of increasing the thermal efficiency of a jaggery installation, a computational fluid dynamic (CFD)-based model was used as a numerical tool to design a fire-tube pan that would replace the existing finned flat pan. For this purpose, the original configuration of the jaggery furnace was simulated via a pre-validated CFD model in order to calculate its current thermal performance. Then, the newly-designed fire-tube pan was virtually replaced in the jaggery furnace with the aim of numerically estimating the thermal performance at the same operating conditions. A comparison of both simulations highlighted the growth of the heat transfer rate at around 105% in the heating/evaporation processes when the fire-tube pan replaced the original finned flat pan. This enhancement impacted the jaggery production installation, whereby the thermal efficiency of the installation increased from 31.4% to 42.8%. Copyright © 2017 Elsevier Ltd. All rights reserved.

PHOTOCHEMICAL HEATING OF DENSE MOLECULAR GAS

Energy Technology Data Exchange (ETDEWEB)

Glassgold, A. E. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Najita, J. R. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

2015-09-10

Photochemical heating is analyzed with an emphasis on the heating generated by chemical reactions initiated by the products of photodissociation and photoionization. The immediate products are slowed down by collisions with the ambient gas and then heat the gas. In addition to this direct process, heating is also produced by the subsequent chemical reactions initiated by these products. Some of this chemical heating comes from the kinetic energy of the reaction products and the rest from collisional de-excitation of the product atoms and molecules. In considering dense gas dominated by molecular hydrogen, we find that the chemical heating is sometimes as large, if not much larger than, the direct heating. In very dense gas, the total photochemical heating approaches 10 eV per photodissociation (or photoionization), competitive with other ways of heating molecular gas.

Industrial excess heat for district heating in Denmark

International Nuclear Information System (INIS)

Bühler, Fabian; Petrović, Stefan; Karlsson, Kenneth; Elmegaard, Brian

2017-01-01

Highlights: •Method for utilisation potential of industrial excess heat for district heating. •Industrial excess heat from thermal processes is quantified at single production units. •Linking of industrial excess heat sources and district heating demands done in GIS. •Excess heat recovery using direct heat transfer and heat pumps. •5.1% of the Danish district heating demand could be supplied by industrial excess heat. -- Abstract: Excess heat is available from various sources and its utilisation could reduce the primary energy use. The accessibility of this heat is however dependent amongst others on the source and sink temperature, amount and potential users in its vicinity. In this work a new method is developed which analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal processes which equals 5.1% of the current demand. More than half of this heat was found to be usable directly, without the need for a heat pump.

Industrial waste heat for district heating

International Nuclear Information System (INIS)

Heitner, K.L.; Brooks, P.P.

1982-01-01

Presents 2 bounding evaluations of industrial waste heat availability. Surveys waste heat from 29 major industry groups at the 2-digit level in Standard Industrial Codes (SIC). Explains that waste heat availability in each industry was related to regional product sales, in order to estimate regional waste heat availability. Evaluates 4 selected industries at the 4-digit SIC level. Finds that industrial waste heat represents a significant energy resource in several urban areas, including Chicago and Los Angeles, where it could supply all of these areas residential heating and cooling load. Points out that there is a strong need to evaluate the available waste heat for more industries at the 4-digit level. Urges further studies to identify other useful industrial waste heat sources as well as potential waste heat users

Synergistic production of hydrogen using fossil fuels and nuclear energy application of nuclear-heated membrane reformer

International Nuclear Information System (INIS)

Hori, M.; Matsui, K.; Tashimo, M.; Yasuda, I.

2004-01-01

Processes and technologies to produce hydrogen synergistically by the steam reforming reaction using fossil fuels and nuclear heat are reviewed. Formulas of chemical reactions, required heats for reactions, saving of fuel consumption or reduction of carbon dioxide emission, possible processes and other prospects are examined for such fossil fuels as natural gas, petroleum and coal. The 'membrane reformer' steam reforming with recirculation of reaction products in a closed loop configuration is considered to be the most advantageous among various synergistic hydrogen production methods. Typical merits of this method are: nuclear heat supply at medium temperature below 600 deg. C, compact plant size and membrane area for hydrogen production, efficient conversion of feed fuel, appreciable reduction of carbon dioxide emission, high purity hydrogen without any additional process, and ease of separating carbon dioxide for future sequestration requirements. With all these benefits, the synergistic production of hydrogen by membrane reformer using fossil fuels and nuclear energy can be an effective solution in this century for the world which has to use. fossil fuels any way to some extent while reducing carbon dioxide emission. For both the fossil fuels industry and the nuclear industry, which are under constraint of resource, environment and economy, this production method will be a viable symbiosis strategy for the coming hydrogen economy era. (author)

Effect of Heating Method on Hydrogen Production by Biomass Gasification in Supercritical Water

Directory of Open Access Journals (Sweden)

Qiuhui Yan

2014-01-01

Full Text Available The glucose as a test sample of biomass is gasified in supercritical water with different heating methods driven by renewable solar energy. The performance comparisons of hydrogen production of glucose gasification are investigated. The relations between temperature raising speed of reactant fluid, variation of volume fraction, combustion enthalpy, and chemical exergy of H2 of the product gases with reactant solution concentration are presented, respectively. The results show that the energy quality of product gases with preheating process is higher than that with no preheating unit for hydrogen production. Hydrogen production quantity and gasification rate of glucose decrease obviously with the increase of concentration of material in no preheating system.

Dissipated energy and entropy production for an unconventional heat engine: the stepwise `circular cycle'

Science.gov (United States)

di Liberto, Francesco; Pastore, Raffaele; Peruggi, Fulvio

2011-05-01

When some entropy is transferred, by means of a reversible engine, from a hot heat source to a colder one, the maximum efficiency occurs, i.e. the maximum available work is obtained. Similarly, a reversible heat pumps transfer entropy from a cold heat source to a hotter one with the minimum expense of energy. In contrast, if we are faced with non-reversible devices, there is some lost work for heat engines, and some extra work for heat pumps. These quantities are both related to entropy production. The lost work, i.e. ? , is also called 'degraded energy' or 'energy unavailable to do work'. The extra work, i.e. ? , is the excess of work performed on the system in the irreversible process with respect to the reversible one (or the excess of heat given to the hotter source in the irreversible process). Both quantities are analysed in detail and are evaluated for a complex process, i.e. the stepwise circular cycle, which is similar to the stepwise Carnot cycle. The stepwise circular cycle is a cycle performed by means of N small weights, dw, which are first added and then removed from the piston of the vessel containing the gas or vice versa. The work performed by the gas can be found as the increase of the potential energy of the dw's. Each single dw is identified and its increase, i.e. its increase in potential energy, evaluated. In such a way it is found how the energy output of the cycle is distributed among the dw's. The size of the dw's affects entropy production and therefore the lost and extra work. The distribution of increases depends on the chosen removal process.

An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

DEFF Research Database (Denmark)

Willems, Cees J. L.; Nick, Hamidreza M.; Weltje, Gert Jan

2017-01-01

Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based...... and minimal required production temperature. The results of this study can be used to minimize negative interference or optimise positive interference aiming at improving geothermal doublet deployment efficiency. (C) 2017 The Authors. Published by Elsevier Ltd....

Heat and light stresses affect metabolite production in the fruit body of the medicinal mushroom Cordyceps militaris.

Science.gov (United States)

Jiaojiao, Zhang; Fen, Wang; Kuanbo, Liu; Qing, Liu; Ying, Yang; Caihong, Dong

2018-05-01

Cordyceps militaris is a highly valued edible and medicinal fungus due to its production of various metabolites, including adenosine, cordycepin, N 6 -(2-hydroxyethyl)-adenosine, and carotenoids. The contents of these metabolites are indicative of the quality of commercially available fruit body of this fungus. In this work, the effects of environmental abiotic factors, including heat and light stresses, on the fruit body growth and metabolite production in C. militaris were evaluated during the late growth stage. The optimal growth temperature of C. militaris was 20 °C. It was found that a heat stress of 25 °C for 5-20 days during the late growth stage significantly promoted cordycepin and carotenoid production without affecting the biological efficiency. Light stress at 6000 lx for 5-20 days during the late growth stage significantly promoted cordycepin production but decreased the carotenoid content. Both heat and light stresses promoted N 6 -(2-hydroxyethyl)-adenosine production. In addition, gene expression analysis showed that there were simultaneous increases in the expression of genes encoding a metal-dependent phosphohydrolase (CCM_04437) and ATP phosphoribosyltransferase (CCM_04438) that are involved in the cordycepin biosynthesis pathway, which was consistent with the accumulation of cordycepin during heat stress for 5-20 days. A positive weak correlation between the cordycepin and adenosine contents was observed with a Pearson correlation coefficient of 0.338 (P fruit body of C. militaris and contribute to further elucidation of the effects of abiotic stress on metabolite accumulation in fungi.

Performances of nuclear power plants for combined production of electricity and hot water for district heating

International Nuclear Information System (INIS)

Bronzen, S.

The possibilities for using nuclear power plants for combined production of heat and power seem to be very good in the future. With the chosen 600 MWsub (e) BWR plant a heat output up to 1200 MW can be arranged. An alternative, consisting of steam extractions from the low-pressure turbine, offers a flexible solution for heat and power generation. With this alternative the combined plant can use components from normal condensing nuclear power plants. The flexible extraction design also offers a real possibility for using the combined plant in electric peak generation. However, urban siting requires long distance heat transmission and the pipe design for this transmission is a major problem when planning and optimizing the whole nuclear combined heat and power plant. (author)

Invisible smoke: third-party endorsement and the resurrection of heat-not-burn tobacco products.

Science.gov (United States)

Elias, Jesse; Ling, Pamela M

2018-06-06

Tobacco companies are introducing new 'heat-not-burn' cigarettes in dozens of countries. Historically, these products failed commercially, and independent researchers contested their health claims. The most prominent early heat-not-burn cigarette was RJ Reynolds's (RJR's) Premier, introduced in the USA in 1988. Curiously, The Lancet endorsed Premier as a 'near-perfect low tar cigarette' in a 1991 editorial, 2 years after Premier had been removed from the market. We examined the context of this endorsement. To ascertain what RJR knew about this endorsement, we systematically searched and analysed previously secret RJR documents in public archives and triangulated the industry document data with other published work. RJR had a long-standing interest in collaborating with outside scientists to endorse potentially reduced harm cigarettes. The author of The Lancet editorial had previously corresponded with RJR regarding Premier's health effects and market potential. Internally, RJR regarded The Lancet 's editorial, its stance on novel tobacco products, and its endorsement of Premier as major successes. While the editorial came too late to save Premier, RJR saw future business opportunities for novel products if endorsed by health authorities. Endorsement by high-impact medical journals and health authorities may be critical in helping heat-not-burn' products succeed where previous attempts have failed. Conflicts of interest influenced these endorsements in the past. Health leaders and academic journals should consider both conflicts of interest and the ethics of endorsing tobacco product substitution, as tobacco companies simultaneously work to promote cigarette smoking and undermine tobacco control globally. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Results of out-of-pile experiments to investigate the possibilities of cooling a core melt with internal heat production

International Nuclear Information System (INIS)

Fieg, G.

1976-01-01

After serious hypothetical reactor accidents, melted core materials with internal heat production can occur in large quantities. A retention of these molten core masses within the containment must be ensured. The knowledge of the heat transport from volume-heated layers is necessary to clarify this matter. (orig./LH) [de

Mathematical modeling of heat transfer in production premises heated by gas infrared emitters

Directory of Open Access Journals (Sweden)

Maksimov Vyacheslav I.

2017-01-01

Full Text Available The results of numerical modeling of the process of free convective heat transfer in the regime of turbulent convection in a closed rectangular region heated by an infrared radiator are presented. The system of Navier-Stokes equations in the Boussinesq approximation is solved, the energy equation for the gas and the heat conduction equations for the enclosing vertical and horizontal walls. A comparative analysis of the heat transfer regimes in the considered region for different Grashof numbers is carried out. The features of the formation of heated air flows relative to the infrared emitter located at some distance from the upper horizontal boundary of the region are singled out.

XML Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

Directory of Open Access Journals (Sweden)

M. R. Monazzam Esmaielpou

2015-09-01

Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced

Study of Heating and Fusion Power Production in ITER Discharges

International Nuclear Information System (INIS)

Rafiq, T.; Kritz, A. H.; Bateman, G.; Kessel, C.; McCune, D. C.; Budny, R. V.; Pankin, A. Y.

2011-01-01

ITER simulations, in which the temperatures, toroidal angular frequency and currents are evolved, are carried out using the PTRANSP code starting with initial profiles and boundary conditions obtained from TSC code studies. The dependence of heat deposition and current drive on ICRF frequency, number of poloidal modes, beam orientation, number of Monte Carlo particles and ECRH launch angles is studied in order to examine various possibilities and contingencies for ITER steady state and hybrid discharges. For the hybrid discharges, the fusion power production and fusion Q, computed using the Multi-Mode MMM v7.1 anomalous transport model, are compared with those predicted using the GLF23 model. The simulations of the hybrid scenario indicate that the fusion power production at 1000 sec will be approximately 500 MW corresponding to a fusion Q = 10.0. The discharge scenarios simulated aid in understanding the conditions for optimizing fusion power production and in examining measures of plasma performance.

A revised ANS standard for decay heat from fission products

International Nuclear Information System (INIS)

Schrock, V.E.

1978-01-01

The draft ANS 5.1 standard on decay heat was published in 1971 and given minor revision in 1973. Its basis was the best estimate working curve developed by K. Shure in 1961. Liberal uncertainties were assigned to the standard values because of lack of data for short cooling times and large discrepancies among experimental data. Research carried out over the past few years has greatly improved the knowledge of this phenomenon and a major revision of the standard has been completed. Very accurate determination of the decay heat is now possible, expecially within the first 10 4 seconds, where the influence of neutron capture in fission products may be treated as a small correction to the idealized zero capture case. The new standard accounts for differences among fuel nuclides. It covers cooling time to 10 9 seconds, but provides only an ''upper bound'' on the capture correction in the interval 10 4 9 seconds. (author)

RF plasma production and heating below ion-cyclotron frequencies in Uragan torsatrons

International Nuclear Information System (INIS)

Moiseenko, V.E.; Berezhnyj, V.L.; Bondarenko, V.N.; Burchenko, P.Ya.; Chechkin, V.V.; Chernyshenko, V.Ya.; Dreval, M.B.; Garkusha, I.E.; Glazunov, G.P.; Grigor'eva, L.I.; Konovalov, V.G.; Kotsubanov, V.D.; Kramskoi, Ye.D.; Kulaga, A.E.; Lozin, A.V.; Castejon, F.; Hidalgo, C.; Hartmann, D.; Koch, R.; Lyssoivan, A.I.

2011-01-01

In the IPP-Kharkiv there are two torsatrons (stellarators) in operation, and in both of them Alfven resonance heating under high-k || conditions is used. This method of heating is advantageous for small-size devices, since in contrast to the minority and second-harmonic heating it can be realized at lower plasma densities. A series of experiments has been performed at the Uragan-3M torsatron with an aim to investigate the features of the discharge with a three-half-turn antenna. Electron temperatures in the T-bar = 0.2-0.5 keV range are achieved at plasma densities n-bar e approx. (0.5-1.5) x 10 13 cm -3 . The plasma energy content has increased by a factor of 2 with respect to the plasma produced with the frame antenna. A new four-strap shielded antenna has been manufactured and installed in the Uragan-2M. A high-frequency discharge for wall conditioning is introduced in the Uragan-2M torsatron. The discharge is sustained by a specially designed small frame antenna, and efficient hydrogen dissociation is achieved. A self-consistent model has been developed for simulation of plasma production in ICRF. The model includes a set of particle and energy-balance equations for the electrons, and the boundary problem for the Maxwell equations. The first calculation results on RF plasma production in the Uragan-2M stellarator with the frame-type antenna are presented.

Periconceptional Heat Stress of Holstein Dams Is Associated with Differences in Daughter Milk Production during Their First Lactation.

Science.gov (United States)

Brown, Britni M; Stallings, Jon W; Clay, John S; Rhoads, Michelle L

2016-01-01

The fertility of lactating Holstein cows is severely reduced during periods of heat stress. Despite this reduction in fertility, however, some inseminations conducted during heat stress result in successful pregnancies from which heifer calves are born. Many of these heifer calves are retained and raised to enter the milking herd as replacement animals. Heat stress experienced by these females around the time they were conceived may confer long-lasting effects that alter subsequent milk production capacity. The objective of this study was to examine the relationship between periconceptional heat stress and subsequent milk production of primiparous cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records included Holstein cows that had completed at least one lactation in one of three states with large populations of dairy cattle and which are known for having hot, humid summers: Georgia, Florida or Texas. Dates of conception were calculated by subtracting 276 d from the recorded birth date of each individual cow. Records for cows conceived within the months of June, July, and August were retained as heat stress-conceived (HSC) cows (n = 94,440); cows conceived within the months of December, January, and February were retained as thermoneutral-conceived (TNC) contemporaries (n = 141,365). In order to account for the effects of environmental conditions on total milk production for a given lactation, cows were blocked by season of calving (winter, spring, summer or fall). Adjusted 305-day mature-equivalent milk production was evaluated with a mixed model ANOVA using SAS, in which random effects were used to account for variability between herds. Of the cows that calved in the summer, fall and winter, TNC cows had higher milk yield than the HSC cows in all states. Interestingly, the cows that calved in the spring presented a unique relationship, with HSC cows producing more milk. Overall however, heat stress at

Periconceptional Heat Stress of Holstein Dams Is Associated with Differences in Daughter Milk Production during Their First Lactation.

Directory of Open Access Journals (Sweden)

Britni M Brown

Full Text Available The fertility of lactating Holstein cows is severely reduced during periods of heat stress. Despite this reduction in fertility, however, some inseminations conducted during heat stress result in successful pregnancies from which heifer calves are born. Many of these heifer calves are retained and raised to enter the milking herd as replacement animals. Heat stress experienced by these females around the time they were conceived may confer long-lasting effects that alter subsequent milk production capacity. The objective of this study was to examine the relationship between periconceptional heat stress and subsequent milk production of primiparous cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records included Holstein cows that had completed at least one lactation in one of three states with large populations of dairy cattle and which are known for having hot, humid summers: Georgia, Florida or Texas. Dates of conception were calculated by subtracting 276 d from the recorded birth date of each individual cow. Records for cows conceived within the months of June, July, and August were retained as heat stress-conceived (HSC cows (n = 94,440; cows conceived within the months of December, January, and February were retained as thermoneutral-conceived (TNC contemporaries (n = 141,365. In order to account for the effects of environmental conditions on total milk production for a given lactation, cows were blocked by season of calving (winter, spring, summer or fall. Adjusted 305-day mature-equivalent milk production was evaluated with a mixed model ANOVA using SAS, in which random effects were used to account for variability between herds. Of the cows that calved in the summer, fall and winter, TNC cows had higher milk yield than the HSC cows in all states. Interestingly, the cows that calved in the spring presented a unique relationship, with HSC cows producing more milk. Overall however

Effects of heat and electricity saving measures in district-heated multistory residential buildings

International Nuclear Information System (INIS)

Truong, Nguyen Le; Dodoo, Ambrose; Gustavsson, Leif

2014-01-01

Highlights: • We analyzed the potential for energy savings in district heated buildings. • Measures that reduce more peak load production give higher primary energy savings. • Efficient appliances increase heat demand but give net primary energy savings. • Efficient appliances give the largest net primary energy savings. - Abstract: The effects of heat and electricity saving measures in district-heated buildings can be complex because these depend not only on how energy is used on the demand side but also on how energy is provided from the supply side. In this study, we analyze the effects of heat and electricity saving measures in multistory concrete-framed and wood-framed versions of an existing district-heated building and examine the impacts of the reduced energy demand on different district heat (DH) production configurations. The energy saving measures considered are for domestic hot water reduction, building thermal envelope improvement, ventilation heat recovery (VHR), and household electricity savings. Our analysis is based on a measured heat load profile of an existing DH production system in Växjö, Sweden. Based on the measured heat load profile, we model three minimum-cost DH production system using plausible environmental and socio-political scenarios. Then, we investigate the primary energy implications of the energy saving measures applied to the two versions of the existing building, taking into account the changed DH demand, changed cogenerated electricity, and changed electricity use due to heat and electricity saving measures. Our results show that the difference between the final and primary energy savings of the concrete-framed and wood-framed versions of the case-study building is minor. The primary energy efficiency of the energy saving measures depends on the type of measure and on the composition of the DH production system. Of the various energy saving measures explored, electricity savings give the highest primary energy savings

Geochemical implications of production and storage control by coupling a direct-use geothermal system with heat networks

NARCIS (Netherlands)

Daniilidis, Alexandros; Scholten, Tjardo; Hooghiem, Joram; Persis, Claudio De; Herber, Rien

2017-01-01

This paper outlines a method in which the heat production of a geothermal system is controlled in relation to the demand from a district-heating network. A model predictive control strategy is designed, which uses volume measurements in the storage tank, and predictions of the demand, to regulate

Nuclear reactor plant for production process heat

International Nuclear Information System (INIS)

Weber, M.

1979-01-01

The high temperature reactor is suitable as a heat source for carrying out endothermal chemical processes. A heat exchanger is required for separating the reactor coolant gases and the process medium. The heat of the reactor is transferred at a temperature lower than the process temperature to a secondary gas and is compressed to give the required temperature. The compression energy is obtained from the same reactor. (RW) [de

Early Age Carbonation Heat and Products of Tricalcium Silicate Paste Subject to Carbon Dioxide Curing

Directory of Open Access Journals (Sweden)

Zhen Li

2018-05-01

Full Text Available This paper presents a study on the carbonation reaction heat and products of tricalcium silicate (C3S paste exposed to carbon dioxide (CO2 for rapid curing. Reaction heat was measured using a retrofitted micro-calorimeter. The highest heat flow of a C3S paste subject to carbonation curing was 200 times higher than that by hydration, and the cumulative heat released by carbonation was three times higher. The compressive strength of a C3S paste carbonated for 2 h and 24 h was 27.5 MPa and 62.9 MPa, respectively. The 24-h carbonation strength had exceeded the hydration strength at 28 days. The CO2 uptake of a C3S paste carbonated for 2 h and 24 h was 17% and 26%, respectively. The X-ray diffraction (XRD, transmission electron microscope coupled with energy dispersive spectrometer (TEM-EDS, and 29Si magic angle spinning–nuclear magnetic resonance (29Si MAS-NMR results showed that the products of a carbonated C3S paste were amorphous silica (SiO2 and calcite crystal. There was no trace of calcium silicate hydrate (C–S–H or other polymorphs of calcium carbonate (CaCO3 detected.

Heat production in growing pigs calculated according to the RQ and CN methods

DEFF Research Database (Denmark)

Christensen, K; Chwalibog, André; Henckel, S

1988-01-01

1. Heat production, calculated according to the respiratory quotient methods, HE(RQ), and the carbon nitrogen balance method, HE(CN), was compared using the results from a total of 326 balance trials with 56 castrated male pigs fed different dietary composition and variable feed levels during...

Residual stresses and their mechanisms of production at circumferential weld by heat-sink welding

International Nuclear Information System (INIS)

Ueda, Yukio; Nakacho, Keiji; Ohkubo, Katsumi; Shimizu, Tsubasa.

1983-01-01

In the previous report, the authors showed effectiveness of the heat-sink welding (water cooling) to accomplish this end by conducting theoretical analysis and an experiment on residual stresses in the 4B pipe of SUS 304 by the conventional welding and the heat-sink welding at a certain standard heat-input condition. In this research, different pipe sizes and varied heat-input are applied. The welding residual stresses by the conventional welding and the heat-sink welding are obtained by the theoretical analysis and their production mechanisms are clarified. Hence the influence of the above changes of conditions on effectiveness of the heat-sink welding is investigated. The main results are summarized as follow. (1) In case of this pipes such as 2B and 4B pipes, it is important to minimize heat-input per one pass (especially for latter half passes) in order to improve the effectiveness of the heat-sink welding. The effectiveness can be predicted either by theoretical analysis of the temperature distribution history with consideration of the characteristic of heat transfer under spray-watering or by experimental measurement. (2) In case of 24B pipes, thick pipes, it is desirable to minimize heat-input for the first half passes, by which the heat-sink welding becomes more effective. In addition, no matter whether the conventional welding or the heat-sink welding, it is important to prevent angular distorsion which produces tensile axial stresses on the inner surface of the pipe in the weld zone. Possible measures to meet these requirements are to apply restraining jigs, to minimize the section area of the groove (ex. application of the narrow gap arc welding), and to change continuous welding to skip one. (J.P.N.)

Literature research on the production, loading, flow, and heat transfer of slush hydrogen

Energy Technology Data Exchange (ETDEWEB)

Park, Young Moo [Dept. of Mechanical Engineering, Ajou University, Wonchon-dong san 5, Paldal-Gu, Suwon 442-749 (Korea, Republic of)

2010-12-15

This study summarizes the available information on slush hydrogen and answer pending engineering questions that arise in the design of slush hydrogen propellant systems. The four methods for the production of slush are discussed. For storage, slush hydrogen must be pressurized, free from impurities, and continuously upgraded. Slush flowing at low flow rates has a higher viscosity than the liquid, however at higher velocities it approaches the viscosity of neat liquid. For the entire range of natural convection and nucleate boiling, the heat transfer at the triple-point temperature and pressure is nearly the same for the liquid and slush. The natural convection from smooth surfaces for slush can be predicted using available correlations. However, for engineering analysis and design of a system involving a slush cryogenic propellant, reliable information is required on production, flow, heat transfer, and instrumentation of these fluids. Some relevant and important aspects of slush hydrogen which have not yet been fully answered are presented. (author)

Thermal-hydraulic process for cooling, heating and power production with low-grade heat sources in residential sector

International Nuclear Information System (INIS)

Borgogno, R.; Mauran, S.; Stitou, D.; Marck, G.

2017-01-01

fluid pairs (R1234yf/R1233zd) is investigated in detail in order to estimate the annual performances. For domestic houses, the process aims at amplifying the solar energy collected by a factor of 1.32 for heating purpose, provides a cold production with a coefficient of performance of 0.4 and generates electricity from the remaining solar energy with an efficiency of 3.7%, reducing the electrical or auxiliary consumption and overall greenhouse gas emissions.

[Application HTST-heating of the mash and its influence on the aroma composition during the production of apple brandy (author's transl)].

Science.gov (United States)

Schreier, P; Drawert, F; Steiger, G

1978-08-18

The influence of HTST-heating of the mash aroma composition during production of apply brandy has been investigated by means of gas chromatography and coupled gas chromatography--mass spectrometry. Starting from the apple aroma the changes in aroma components were studied quantitatively during the conventional production (without enzyme inhibition) as well as after HTST-heating (enzyme inactivation) of the mash. For this purpose 98 aroma compounds were determined in the course of mash production, fermentation and distillation. When employing HTST-heating the original aroma components of the apple particularly the fruit esters were present in appreciably higher concentrations in the mash as well as in the distillate than with the conventional production method. Simultaneously HTST-heating reduced the secondary aroma substances in mash and distillate which are formed with the conventional method by enzymatic-oxidative processes. In the unaged apple brandy obtained from HTST-treated mash lower amounts of lactates and higher concentrations of acetals were found compared with the conventionally produced distillate.

Techno-economic Assessment of Integrated Hydrothermal Liquefaction and Combined Heat and Power Production from Lignocellulose Residues

Directory of Open Access Journals (Sweden)

Mohamed Magdeldin

2018-03-01

Full Text Available Waste biomass as a mean for global carbon dioxide emissions mitigation remains under-utilized. This is mainly due to the low calorific value of virgin feedstock, characterized generally with high moisture content. Aqueous processing, namely hydrothermal liquefaction in subcritical water conditions, has been demonstrated experimentally to thermally densify solid lignocellulose into liquid fuels without the pre-requisite and energy consuming drying step. This study presents a techno-economic evaluation of an integrated hydrothermal liquefaction system with downstream combined heat and power production from forest residues. The utilization of the liquefaction by-products and waste heat from the elevated processing conditions, coupled with the chemical upgrading of the feedstock enables the poly-generation of biocrude, electricity and district heat. The plant thermal efficiency increases by 3.5 to 4.6% compared to the conventional direct combustion case. The economic assessment showed that the minimum selling price of biocrude, based on present co-products market prices, hinders commercialization and ranges between 138 EUR to 178 EUR per MWh. A sensitivity analysis and detailed discussion on the techno-economic assessment results are presented for the different process integration and market case scenarios.

Assessment of advanced small-scale combined heat and power production

Energy Technology Data Exchange (ETDEWEB)

Spitzer, J. [Joanneum Research (Austria)

1996-12-31

To increase the share of renewable energy sources, bioenergy has to be used for electricity generation, preferably in combined heat and power (CHP) production systems, besides its traditional use in space heating. The need for small-scale, i.e. below 5 MW{sub el}, CHP production arises from the fact that a considerable portion of the available solid biofuels may not be transported over long distances for economic reasons and that in many cases the heat demand is below 10 MW{sub el} in district heating schemes in communities with less than 10 000 inhabitants. The available technical options have to be assessed with respect to performance, reliability and economy. Such an assessment has been performed in a study where the following options have been compared: Gasification - combustion engine or gas turbine; Combustion - steam turbine/engine; Combustion - hot air turbine; Combustion - Stirling engine. While conventional steam cycle systems are available and reliable they are generally not economical in the power range under consideration. Among the other systems, which are not yet commercially available, the Stirling engine system seems to be attractive in the power range below 500 kW{sub el} and the hot air system could close the gap to the steam cycle systems, i.e. cover the power range between 0.5 and 5.0 MW{sub el}. Gasification schemes seem less suitable: The power generation part (combustion engine and gas turbine) is well established for natural gas, with the combustion engine in the lower (<5 MW{sub el}) and the gas turbine in the higher (>5MW{sub el}) power range. However, the gas quality needed for the operation of a combustion engine requires expensive pre-treatment of the gas from wood gasification so that this scheme is less attractive for the power range under consideration. These conclusions lead to R and D efforts in Austria in two directions: Hot air turbine: A utility demonstration plant is under construction with a power of 1 600 kW{sub el

Assessment of advanced small-scale combined heat and power production

Energy Technology Data Exchange (ETDEWEB)

Spitzer, J [Joanneum Research (Austria)

1997-12-31

To increase the share of renewable energy sources, bioenergy has to be used for electricity generation, preferably in combined heat and power (CHP) production systems, besides its traditional use in space heating. The need for small-scale, i.e. below 5 MW{sub el}, CHP production arises from the fact that a considerable portion of the available solid biofuels may not be transported over long distances for economic reasons and that in many cases the heat demand is below 10 MW{sub el} in district heating schemes in communities with less than 10 000 inhabitants. The available technical options have to be assessed with respect to performance, reliability and economy. Such an assessment has been performed in a study where the following options have been compared: Gasification - combustion engine or gas turbine; Combustion - steam turbine/engine; Combustion - hot air turbine; Combustion - Stirling engine. While conventional steam cycle systems are available and reliable they are generally not economical in the power range under consideration. Among the other systems, which are not yet commercially available, the Stirling engine system seems to be attractive in the power range below 500 kW{sub el} and the hot air system could close the gap to the steam cycle systems, i.e. cover the power range between 0.5 and 5.0 MW{sub el}. Gasification schemes seem less suitable: The power generation part (combustion engine and gas turbine) is well established for natural gas, with the combustion engine in the lower (<5 MW{sub el}) and the gas turbine in the higher (>5MW{sub el}) power range. However, the gas quality needed for the operation of a combustion engine requires expensive pre-treatment of the gas from wood gasification so that this scheme is less attractive for the power range under consideration. These conclusions lead to R and D efforts in Austria in two directions: Hot air turbine: A utility demonstration plant is under construction with a power of 1 600 kW{sub el

Memory behaviors of entropy production rates in heat conduction

Science.gov (United States)

Li, Shu-Nan; Cao, Bing-Yang

2018-02-01

Based on the relaxation time approximation and first-order expansion, memory behaviors in heat conduction are found between the macroscopic and Boltzmann-Gibbs-Shannon (BGS) entropy production rates with exponentially decaying memory kernels. In the frameworks of classical irreversible thermodynamics (CIT) and BGS statistical mechanics, the memory dependency on the integrated history is unidirectional, while for the extended irreversible thermodynamics (EIT) and BGS entropy production rates, the memory dependences are bidirectional and coexist with the linear terms. When macroscopic and microscopic relaxation times satisfy a specific relationship, the entropic memory dependences will be eliminated. There also exist initial effects in entropic memory behaviors, which decay exponentially. The second-order term are also discussed, which can be understood as the global non-equilibrium degree. The effects of the second-order term are consisted of three parts: memory dependency, initial value and linear term. The corresponding memory kernels are still exponential and the initial effects of the global non-equilibrium degree also decay exponentially.

Occupational heat stress and associated productivity loss estimation using the PHS model (ISO 7933): a case study from workplaces in Chennai, India

Science.gov (United States)

Lundgren, Karin; Kuklane, Kalev; Venugopal, Vidhya

2014-01-01

Background Heat stress is a major occupational problem in India that can cause adverse health effects and reduce work productivity. This paper explores this problem and its impacts in selected workplaces, including industrial, service, and agricultural sectors in Chennai, India. Design Quantitative measurements of heat stress, workload estimations, and clothing testing, and qualitative information on health impacts, productivity loss, etc., were collected. Heat strain and associated impacts on labour productivity between the seasons were assessed using the International Standard ISO 7933:2004, which applies the Predicted Heat Strain (PHS) model. Results and conclusions All workplaces surveyed had very high heat exposure in the hot season (Wet Bulb Globe Temperature x¯ =29.7), often reaching the international standard safe work values (ISO 7243:1989). Most workers had moderate to high workloads (170–220 W/m2), with some exposed to direct sun. Clothing was found to be problematic, with high insulation values in relation to the heat exposure. Females were found to be more vulnerable because of the extra insulation added from wearing a protective shirt on top of traditional clothing (0.96 clo) while working. When analysing heat strain – in terms of core temperature and dehydration – and associated productivity loss in the PHS model, the parameters showed significant impacts that affected productivity in all workplaces, apart from the laundry facility, especially during the hot season. For example, in the canteen, the core temperature limit of 38°C predicted by the model was reached in only 64 min for women. With the expected increases in temperature due to climate change, additional preventive actions have to be implemented to prevent further productivity losses and adverse health impacts. Overall, this study presented insight into using a thermo-physiological model to estimate productivity loss due to heat exposure in workplaces. This is the first time the PHS

Occupational heat stress and associated productivity loss estimation using the PHS model (ISO 7933): a case study from workplaces in Chennai, India.

Science.gov (United States)

Lundgren, Karin; Kuklane, Kalev; Venugopal, Vidhya

2014-01-01

Heat stress is a major occupational problem in India that can cause adverse health effects and reduce work productivity. This paper explores this problem and its impacts in selected workplaces, including industrial, service, and agricultural sectors in Chennai, India. Quantitative measurements of heat stress, workload estimations, and clothing testing, and qualitative information on health impacts, productivity loss, etc., were collected. Heat strain and associated impacts on labour productivity between the seasons were assessed using the International Standard ISO 7933:2004, which applies the Predicted Heat Strain (PHS) model. All workplaces surveyed had very high heat exposure in the hot season (Wet Bulb Globe Temperature =29.7), often reaching the international standard safe work values (ISO 7243:1989). Most workers had moderate to high workloads (170-220 W/m2), with some exposed to direct sun. Clothing was found to be problematic, with high insulation values in relation to the heat exposure. Females were found to be more vulnerable because of the extra insulation added from wearing a protective shirt on top of traditional clothing (0.96 clo) while working. When analysing heat strain--in terms of core temperature and dehydration--and associated productivity loss in the PHS model, the parameters showed significant impacts that affected productivity in all workplaces, apart from the laundry facility, especially during the hot season. For example, in the canteen, the core temperature limit of 38°C predicted by the model was reached in only 64 min for women. With the expected increases in temperature due to climate change, additional preventive actions have to be implemented to prevent further productivity losses and adverse health impacts. Overall, this study presented insight into using a thermo-physiological model to estimate productivity loss due to heat exposure in workplaces. This is the first time the PHS model has been used for this purpose. An exploratory

Occupational heat stress and associated productivity loss estimation using the PHS model (ISO 7933: a case study from workplaces in Chennai, India

Directory of Open Access Journals (Sweden)

Karin Lundgren

2014-11-01

Full Text Available Background: Heat stress is a major occupational problem in India that can cause adverse health effects and reduce work productivity. This paper explores this problem and its impacts in selected workplaces, including industrial, service, and agricultural sectors in Chennai, India. Design: Quantitative measurements of heat stress, workload estimations, and clothing testing, and qualitative information on health impacts, productivity loss, etc., were collected. Heat strain and associated impacts on labour productivity between the seasons were assessed using the International Standard ISO 7933:2004, which applies the Predicted Heat Strain (PHS model. Results and conclusions: All workplaces surveyed had very high heat exposure in the hot season (Wet Bulb Globe Temperature x¯ =29.7, often reaching the international standard safe work values (ISO 7243:1989. Most workers had moderate to high workloads (170–220 W/m2, with some exposed to direct sun. Clothing was found to be problematic, with high insulation values in relation to the heat exposure. Females were found to be more vulnerable because of the extra insulation added from wearing a protective shirt on top of traditional clothing (0.96 clo while working. When analysing heat strain – in terms of core temperature and dehydration – and associated productivity loss in the PHS model, the parameters showed significant impacts that affected productivity in all workplaces, apart from the laundry facility, especially during the hot season. For example, in the canteen, the core temperature limit of 38°C predicted by the model was reached in only 64 min for women. With the expected increases in temperature due to climate change, additional preventive actions have to be implemented to prevent further productivity losses and adverse health impacts. Overall, this study presented insight into using a thermo-physiological model to estimate productivity loss due to heat exposure in workplaces. This is the

Periconceptional Heat Stress of Holstein Dams Is Associated with Differences in Daughter Milk Production and Composition during Multiple Lactations.

Directory of Open Access Journals (Sweden)

Britni M Brown

Full Text Available Heat stress at the time of conception affects the subsequent milk production of primiparous Holstein cows; however, it is unknown whether these effects are maintained across multiple lactations. Therefore, the objective of the current study was to examine the relationship between periconceptional heat stress and measurements of milk production and composition in cows retained within a herd for multiple lactations. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records included milk production data and milk composition data from over 75,000 and 44,000 Holstein cows, respectively, born between 2000 and 2010 in Florida, Georgia, and Texas. Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as heat stress conceived (HSC cows; cows conceived within the months of December, January, and February were retained as thermoneutral conceived (TNC contemporaries. Adjusted 305-d mature equivalent milk, protein percent and fat percent were evaluated with a mixed model ANOVA using SAS. Milk production was significantly affected by periconceptional heat stress. When a significant difference or tendency for a difference was detected between the HSC and TNC cows, the TNC produced more milk in all but one comparison. The advantage in milk production for the TNC cows over the HSC cows ranged from 82 ± 42 to 399 ± 61 kg per lactation. Alterations in fat and protein percentage were variable and most often detected in first lactations (first > second or third. Overall, the most striking result of this study is the consistency of the relationship between HSC and milk production. The nature of this relationship suggests that heat stress at or around the time of conception impairs cow milk yield throughout her lifetime.

Thermodynamic evaluation of chemical looping combustion for combined cooling heating and power production driven by coal

International Nuclear Information System (INIS)

Fan, Junming; Hong, Hui; Zhu, Lin; Wang, Zefeng; Jin, Hongguang

2017-01-01

Highlights: • An ex-situ coal gasification chemical looping combustion integrated with CCHP process has been presented. • This novel process maintains a maximum energy efficiency of 60.34%. • The fossil energy saving ratio of this process is optimize to be 27.20%. - Abstract: This study carries out an investigation concerning on the benefits of ex-situ coal gasification chemical looping combustion integrated with combined cooling, heating and power generation (CCHP-CLC) by means of thermodynamic evaluation. The coal gasification syngas is introduced into chemical looping combustion for inherent separation of CO_2 without extra energy consumed. The combustion flue gases from both air reactor and fuel reactor are sequentially fed into gas turbines for electricity production, a heat recovery vapor generator unit for further electricity generation with driving a LiBr-H_2O absorption chiller for cooling production in summer and finally a heat exchanger for daily heat water production. A preliminary parameter analysis helps to obtain the optimum operating condition, as steam-to-coal ratio (S/C) of 0.05, oxygen-to-coal ratio (O/C) of 0.75, and operating pressure of chemical looping combustion process of 5 bar. The overall energy efficiency of the CCHP-CLC process is calculated equal to 58.20% in summer compared with that of 60.34% in winter. Importantly, by utilization of such process, the reduction potential of fossil fuel (coal) consumption has been demonstrated to be 23.36% in summer and 27.20% in winter.

Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt

International Nuclear Information System (INIS)

Abbady, Adel G.E.; El-Arabi, A.M.; Abbady, A.

2006-01-01

Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 μW m -3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 μW m -3 (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites

Heat production rate from radioactive elements in igneous and metamorphic rocks in eastern desert, Egypt

International Nuclear Information System (INIS)

Abbady, A G.E.; Arabi, A.M.; Abbay, A.

2005-01-01

Radioactive heat - production data of igneous and metamorphic rocks cropping out from the eastern desert are presented. Samples were analysed using low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 Μ Wm-3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite) to 0.91 (metagabroo) Μ W.m-3. The contribution due to U is about (51%), whereas that of Th (31%) and (18%) by K. The corresponding values in igneous rocks are 76%: 19%: 5%, respectively. The calculated values showed good agreement with global values expect in some areas contained granite rocks

Heat pump heating with heat pumps driven by combustion engines or turbines

Energy Technology Data Exchange (ETDEWEB)

Hein, K

1977-01-27

The heat pump described is driven by a gas Otto cycle engine, or a gas- or light- or heavy-oil fired Diesel engine. The claim refers to the use of waste heat of the engines by feeding into the input circuit of the heat pump. In addition, a drive by an electrical motor-generator or power production can be selected at times of peak load in the electrical supply network.

Efficient hydrogen production using heat in neutron shield of fusion reactor

International Nuclear Information System (INIS)

Okano, Kunihiko; Asaoka, Yoshiyuki; Hiwatari, Ryouji; Yoshida, Tomoaki

2001-01-01

In future perspective of energy supply, a hydrogen energy cycle is expected to play an important role as a CO 2 free fuel for mobile or co-generation systems. Fusion power plants should offer advantages, compatibilities and/or synergistic effects with or in such future energy systems. In this paper, a comprehensive power station, in which a fusion plant is integrated with a hydrogen production plant, is proposed. A tenuous heat source in the outboard shield, which is unsuitable to produce high-pressure and high-temperature steam for efficient electric power generation, is used for the hydrogen production. This integrated system provides some synergistic effects and it would be advantageous over any independent use of each plant. (author)

Heat transfer characteristics evaluation of heat exchangers of mock-up test facility with full-scale reaction tube for HTTR hydrogen production system (Contract research)

International Nuclear Information System (INIS)

Shimizu, Akira; Ohashi, Hirofumi; Kato, Michio; Hayashi, Koji; Aita, Hideki; Nishihara, Tetsuo; Inaba, Yoshitomo; Takada, Shoji; Morisaki, Norihiro; Sakaki, Akihiro; Maeda, Yukimasa; Sato, Hiroyuki; Inagaki, Yoshiyuki; Hanawa, Hiromi; Fujisaki, Katsuo; Yonekawa, Hideo

2005-06-01

Connection of hydrogen production system by steam reforming of methane to the High Temperature Engineering Test Reactor (HTTR) of the Japan Atomic Energy Research Institute (JAERI) has been surveyed until now. Mock-up test facility of this steam reforming system with full-scale reaction tube was constructed in FY 2001 and hydrogen of 120 Nm 3 /h was successfully produced in overall performance test. Totally 7 times operational tests were performed from March 2002 to December 2004. A lot of operational test data on heat exchanges were obtained in these tests. In this report specifications and structures of steam reformer, steam superheater, steam generator, condenser, helium gas cooler, feed gas heater and feed gas superheater were described. Heat transfer correlation equations for inside and outside tube were chosen from references. Spreadsheet programs were newly made to evaluate heat transfer characteristics from measured test data such as inlet and outlet temperature pressure and flow-rate. Overall heat-transfer coefficients obtained from the experimental data were compared and evaluated with the calculated values with heat transfer correlation equation. As a result, actual measurement values of all heat exchangers gave close agreement with the calculated values with correlation equations. Thermal efficiencies of the heat exchangers were adequate as they were well accorded with design value. (author)

Advanced Intermediate Heat Transport Loop Design Configurations for Hydrogen Production Using High Temperature Nuclear Reactors

International Nuclear Information System (INIS)

Chang Oh; Cliff Davis; Rober Barner; Paul Pickard

2005-01-01

The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed to perform thermal-hydraulic evaluations and cycle-efficiency evaluations of the different configurations and coolants. The thermal-hydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. The relative sizes of components provide a relative indication of the capital cost associated with the various configurations. Estimates of the overall cycle efficiency of the various

Inventory of future power and heat production technologies. Partial report Energy combines

International Nuclear Information System (INIS)

Thunman, Henrik; Lind, Fredrik; Johnsson, Filip

2008-12-01

This report treats different ways to produce various upgraded biofuels from lignocellulosic materials in so called polygeneration processes. Furthermore the different upgrading technologies are also investigated with respect to co-production of heat and power. The processes investigated are linked to production of - bio pellets (or lignin pellets), dried, grinded and compressed biomass (or lignin); - torrified bio pellets, dried, grinded, heat treated and compressed biomass; - bio-oils or pyrolytic oils, liquefied biomass with crude oil quality; - ethanol via hydrolysis (process where the biomass is divided into sugars and lignin) followed by fermentation; - methane via hydrolysis and fermentation; - methane via indirect gasification and methane via indirect or suspension gasification, - DME (dimethyl ether) via indirect or suspension gasification; - methanol via indirect or suspension gasification; - DME and methanol via methane produced via indirect gasification. Lignocellulosic biomasses are, for example, forest residues or biomass that can be cultivated on degraded lands. The result from this report shows that it is only the production of bio pellets that is fully commercially available today. For all the other polygeneration processes investigated the production of bio-oil and torrified bio pellets stands out from the other processes investigated, as it is the market for the product that holds back the introduction of the technology. For the other technologies one or several components are still not commercialized and the challenges for these technologies are described in the report. Summarizing the efficiencies for the different processes, the processes that produces biofuels for stationary applications, bio pellets, torrified bio pellets and bio-oil, show the highest efficiencies. Accounted for the co-generated power, efficiencies up to 90 % based on ingoing lower heating values of the dry substance fed to the process could be achieved. For the processes

Effects of heat treatment on antioxidative and anti-inflammatory properties of orange by-products

Science.gov (United States)

This study investigated the changes in functional components, antioxidative activities, antibacterial activities, anti-inflammatory activities of orange (Citrus sinensis (L.) Osbeck) by-products (OBP) by heat treatment at 50 and 100 degrees C (hereafter, 50D and 100D extracts, respectively). Optimal...

Co-composting of eggshell waste in self-heating reactors: monitoring and end product quality

OpenAIRE

Soares, Micaela A. R.; Quina, Margarida M. J.; Quinta-Ferreira, Rosa M.

2013-01-01

Industrial eggshell waste (ES) is classified as an animal by-product not intended to human consumption. For reducing pathogen spreading risk due to soil incorporation of ES, sanitation by composting is a pre-treatment option. This work aims to evaluate eggshell waste recycling in self-heating composting reactors and investigate ES effect on process evolution and end product quality. Potato peel, grass clippings and rice husks were the starting organic materials considered. The incorporati...

Luminescence property and large-scale production of ZnO nanowires by current heating deposition

International Nuclear Information System (INIS)

Singjai, P.; Jintakosol, T.; Singkarat, S.; Choopun, S.

2007-01-01

Large-scale production for ZnO nanowires has been demonstrated by current heating deposition. Based on the use of a solid-vapor phase carbothermal sublimation technique, a ZnO-graphite mixed rod was placed between two copper bars and gradually heated by passing current through it under constant flowing of argon gas at atmospheric pressure. The product seen as white films deposited on the rod surface was separated for further characterizations. The results have shown mainly comb-like structures of ZnO nanowires in diameter ranging from 50 to 200 nm and length up to several tens micrometers. From optical testing, ionoluminescence spectra of as-grown and annealed samples have shown high green emission intensities centered at 510 nm. In contrast, the small UV peak centered at 390 nm was observed clearly in the as-grown sample which almost disappeared after the annealing treatment

Maillard reaction products from highly heated food prevent mast cell number increase and inflammation in a mouse model of colitis.

Science.gov (United States)

Al Amir, Issam; Dubayle, David; Héron, Anne; Delayre-Orthez, Carine; Anton, Pauline M

2017-12-01

Links between food and inflammatory bowel diseases (IBDs) are often suggested, but the role of food processing has not been extensively studied. Heat treatment is known to cause the loss of nutrients and the appearance of neoformed compounds such as Maillard reaction products. Their involvement in gut inflammation is equivocal, as some may have proinflammatory effects, whereas other seem to be protective. As IBDs are associated with the recruitment of immune cells, including mast cells, we raised the hypothesis that dietary Maillard reaction products generated through heat treatment of food may limit the colitic response and its associated recruitment of mast cells. An experimental model of colitis was used in mice submitted to mildly and highly heated rodent food. Adult male mice were divided in 3 groups and received nonheated, mildly heated, or highly heated chow during 21 days. In the last week of the study, each group was split into 2 subgroups, submitted or not (controls) to dextran sulfate sodium (DSS) colitis. Weight variations, macroscopic lesions, colonic myeloperoxidase activity, and mucosal mast cell number were evaluated at the end of the experiment. Only highly heated chow significantly prevented DSS-induced weight loss, myeloperoxidase activity, and mast cell number increase in the colonic mucosa of DSS-colitic mice. We suggest that Maillard reaction products from highly heated food may limit the occurrence of inflammatory phases in IBD patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Heat flow in Indian Gondwana basins and heat production of their basement rocks

Energy Technology Data Exchange (ETDEWEB)

Rao, G.V.; Rao, R.U.M.

1983-01-01

Temperatures have been measured in eight boreholes (ranging from 260 to 800 m in depth) in five Gondwana basins of the Damodar and Son valleys. With the aid of about 250 thermal conductivity determinations on core samples from these holes, heat flow has been evaluated. Measurements of radioactive heat generation have been made on samples of Precambrian gneisses constituting the basement for the Sonhat (Son valley) and Chintalapudi (Godavari valley) basins. Heat-flow values from all of the Damodar valley basins are within the narrow range of 69-79 mW/m exp(2). The value from the Sonhat basin (107 mW/m exp(2)) is significantly higher. The generally high heat flows observed in Gondwana basins of India cannot be attributed to the known tectonism or igneous activity associated with these basins. The plots of heat flow vs. heat generation for three Gondwana basins (Jharia, Sonhat and Chintalapudi) are on the same line as those of three regions in the exposed Precambrian crystalline terrains in the northern part of the Indian shield. This indicates that the crust under exposed regions of the Precambrian crystalline rocks as well as the Gondwana basins, form an integral unit as far as the present-day geothermal character is concerned. (5 figs., 14 refs., 4 tables).

Heat flow in Indian Gondwana basins and heat production of their basement rocks

Science.gov (United States)

Rao, G. V.; Rao, R. U. M.

1983-01-01

Temperatures have been measured in eight boreholes (ranging from 260 to 800 m in depth) in five Gondwana basins of the Damodar and Son valleys. With the aid of about 250 thermal conductivity determinations on core samples from these holes, heat flow has been evaluated. Measurements of radioactive heat generation have been made on samples of Precambrian gneisses constituting the basement for the Sonhat (Son valley) and Chintalapudi (Godavari valley) basins. Heat-flow values from all of the Damodar valley basins are within the narrow range of 69-79 mW/m 2. The value from the Sonhat basin (107 mW/m 2) is significantly higher. The generally high heat flows observed in Gondwana basins of India cannot be attributed to the known tectonism or igneous activity associated with these basins. The plots of heat flow vs. heat generation for three Gondwana basins (Jharia, Sonhat and Chintalapudi) are on the same line as those of three regions in the exposed Precambrian crystalline terrains in the northern part of the Indian shield. This indicates that the crust under exposed regions of the Precambrian crystalline rocks as well as the Gondwana basins, form an integral unit as far as the present-day geothermal character is concerned.

Heat and Mass Transfer Measurements for Tray-Fermented Fungal Products

Science.gov (United States)

Jou, R.-Y.; Lo, C.-T.

2011-01-01

In this study, heat and mass transfer in static tray fermentation, which is widely used in solid-state fermentation (SSF) to produce fungal products, such as enzymes or koji, is investigated. Specifically, kinetic models of transport phenomena in the whole-tray chamber are emphasized. The effects of temperature, moisture, and humidity on microbial growth in large-scale static tray fermentation are essential to scale-up SSF and achieve uniform fermentation. In addition, heat and mass transfer of static tray fermentation of Trichoderma fungi with two tray setups—traditional linen coverings and stacks in a temperature-humidity chamber is examined. In both these setups, the following factors of fermentation were measured: air velocity, air temperature, illumination, pH, carbon dioxide (CO2) concentration, and substrate temperature, and the effects of bed height, moisture of substrate, and relative humidity of air are studied. A thin (1 cm) bed at 28 °C and 95 % relative humidity is found to be optimum. Furthermore, mixing was essential for achieving uniform fermentation of Trichoderma fungi. This study has important applications in large-scale static tray fermentation of fungi.

Manufacture of power station heat exchangers using modern production technology

International Nuclear Information System (INIS)

Genzlinger, W.; Hoffmann, J.; Ohlhaeuser, K.

1986-01-01

Heat exchangers of high quality and operational safety can only be fabricated economically if fabrication is as 'simple' as possible and can be controlled and if, through value analysis, the work flows can be mechanized and automated and the following requirements are met: use of materials that are easy to work with for the application considered, choice of product designs and wall thicknesses that offer favourable conditions for processing and non-destructive testing, placing of seams in such a way that good accessibility for welding and minimum residual welding stresses are assured, minimizing the number of welding seams, use of automatic welding machines for submerged-arc welding and electronically controlled sources of welding current - semi-automatic equipment for spatter-free interfaces (pulse technique), electronically controlled equipment for welding in rollers and pipes and CNC-controlled machining centres for drilling pipe galleries (deep-hole drilling) and baffle plates and for machining the sealing elements after welding. Continuous inspections in each phase of fabrication assures that heat exchangers are made which fully meet the requirements of nuclear power station operators. (orig.)

District heat production by means of a heat-pump operated by natural gas. Draft design of a 1 MW heat pump operated by a gas engine. Project sponsored by energy research program 1981 of the Danish Ministry of Energy. Fjernvarmeproduktion med naturgasdrevet varmepumpe. Skitseprojektering af 1 MW gasmotordrevet varmepumpe. Udfoert under Energiministeriets energiforskningsprogram 1981

Energy Technology Data Exchange (ETDEWEB)

Evald, A.

1982-01-01

The aim of this project is an investigation of the technical and economic aspects of using natural gas in a gas engine driven heat pump for heat production in district heating nets and large housing blocks. The gas engine is a turbocharged spark-ignition gas engine with a performance of 35%. The heat produced by the engine in cylinderjackets, exhaust gas etc. is utilized in the heating system. The engine drives a screw-, piston- or turbocompressor heat pump, applicated with a heat exchanger for liquid refrigerant from the condenser and an economizer for flashing off vapour at an intermediate pressure. Waste water, seawater, ground water or even outdoor air can be used as heat source for the evaporator. The COP for the heat pump is calculated to 3.1 to 3.3 under normal operating conditions. For the total system containing gas engine and heat pump, the primary energy ratio - defined as the ratio of heat production to heat of combustion of the gas - is calculated to be 1.61 to 1.66. The size of the plant is 1 MW heat production. The economy seems to be reasonable good with a payback period of 4 years and a payout period of 5 years wich should be compared with the expected life time of 15 years for the plant. The projected plant shows several advantages as regards the environmental considerations compared with heat production in a boiler based on oil or coal.

Analysis of the heat transfer in double and triple concentric tube heat exchangers

Science.gov (United States)

Rădulescu, S.; Negoiţă, L. I.; Onuţu, I.

2016-08-01

The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

Thermal performance analysis of Brayton cycle with waste heat recovery boiler for diesel engines of offshore oil production facilities

International Nuclear Information System (INIS)

Liu, Xianglong; Gong, Guangcai; Wu, Yi; Li, Hangxin

2016-01-01

Highlights: • Comparison of Brayton cycle with WHRB adopted in diesel engines with and without fans by thermal performance. • Waste heat recovery technology for FPSO. • The thermoeconomic analysis for the heat recovery for FPSO. - Abstract: This paper presents the theoretical analysis and on-site testing on the thermal performance of the waste heat recovery system for offshore oil production facilities, including the components of diesel engines, thermal boilers and waste heat boilers. We use the ideal air standard Brayton cycle to analyse the thermal performance. In comparison with the traditional design, the fans at the engine outlet of the waste heat recovery boiler is removed due to the limited space of the offshore platform. The cases with fan and without fan are compared in terms of thermal dynamics performance, energy efficiency and thermo-economic index of the system. The results show that the application of the WHRB increases the energy efficiency of the whole system, but increases the flow resistance in the duct. It is proved that as the waste heat recovery boiler takes the place of the thermal boiler, the energy efficiency of whole system without fan is slightly reduced but heat recovery efficiency is improved. This research provides an important guidance to improve the waste heat recovery for offshore oil production facilities.

Industrial excess heat for district heating in Denmark

DEFF Research Database (Denmark)

Bühler, Fabian; Petrovic, Stefan; Karlsson, Kenneth Bernard

2017-01-01

analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate...... the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity...... analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal...

Internally Heated Screw Pyrolysis Reactor (IHSPR) heat transfer performance study

Science.gov (United States)

Teo, S. H.; Gan, H. L.; Alias, A.; Gan, L. M.

2018-04-01

1.5 billion end-of-life tyres (ELT) were discarded globally each year and pyrolysis is considered the best solution to convert the ELT into valuable high energy-density products. Among all pyrolysis technologies, screw reactor is favourable. However, conventional screw reactor risks plugging issue due to its lacklustre heat transfer performance. An internally heated screw pyrolysis reactor (IHSPR) was developed by local renewable energy industry, which serves as the research subject for heat transfer performance study of this particular paper. Zero-load heating test (ZLHT) was first carried out to obtain the operational parameters of the reactor, followed by the one dimensional steady-state heat transfer analysis carried out using SolidWorks Flow Simulation 2016. Experiments with feed rate manipulations and pyrolysis products analyses were conducted last to conclude the study.

Combined heat and power production planning in a waste-to-energy plant on a short-term basis

International Nuclear Information System (INIS)

Touš, Michal; Pavlas, Martin; Putna, Ondřej; Stehlík, Petr; Crha, Lukáš

2015-01-01

In many cases, WtE (waste-to-energy) plants are CHP (combined heat and power) producers. They are often integrated into a central heating system and they also export electricity to the grid. Therefore, they have to plan their operation on a long-term basis (months, years) as well as on a short-term basis (hours, days). Simulation models can effectively support decision making in CHP production planning. In general, CHP production planning on a short-term basis is a challenging task for WtE plants. This article presents a simulation based support. It is demonstrated on an example involving a real WtE plant. Most of the models of relevant WtE sub-systems (boilers, steam turbine) are developed using operational data and applying linear regression and artificial neural network technique. The process randomness given mainly by fluctuating heating value of waste leads to uncertainty in a calculation of CHP production and a stochastic approach is appropriate. The models of the sub-systems are, therefore, extended of a stochastic part and Monte-Carlo simulation is applied. Compared to the current planning strategy in the involved WtE plant, the stochastic simulation based planning provides increased CHP production resulting in better net thermal efficiency and increased revenue. This is demonstrated through a comparison using real operational data. - Highlights: • Introduction of a stochastic model of a CHP production in a waste-to-energy plant. • An application of the model for the next day CHP production planning. • Better net thermal efficiency and therefore increased revenue achieved.

High temperature heat exchange: nuclear process heat applications

International Nuclear Information System (INIS)

Vrable, D.L.

1980-09-01

The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment

Radionuclide concentration in fuels and ash products from biofuel heating plants

International Nuclear Information System (INIS)

Erlandsson, B.; Hedvall, R.; Mattsson, S.

1995-01-01

The activity concentration of the radionuclides K-40, Ac-228, Pa-234, Mn-54, Co-60, Zr-95, Ru-106, Ag-110m, Sb-125, Cs-134, Cs-137 and Ce-144 have been investigated in peat wood chips and ash products from 13 Swedish district heating plants during the winter seasons of 1986/1987, 1988/89, 1989/90 and 1990/91. There is a significant decrease in the activity concentration of Cs-137 in the fuel which is especially pronounced between the first two seasons, 86/87 and 88/89 after the Chernobyl accident. In spite of the varying deposition of Cs-137 over the country it has been possible to give a relation between the activity concentration in the peat and wood chips as a function of the deposition. The Swedish biofuel heating plants of which 35-40 are burning peat and 70-75 chips have been divided in three groups according to the activity concentration in the ash products. The mean Cs-137 concentration in ash and the total activity 'produced' per year in Sweden have been calculated. The maximum concentration in air at ground level and the corresponding effective dose rate of inhaled Cs-137 as a function of the emission rates of flue gases from stacks with varying heights and during different weather conditions has been calculated. 16 refs, 18 tabs, 4 figs

Method to treat a product infested with microorganisms with ionizing radiation and heat

International Nuclear Information System (INIS)

Gruenewald, T.

1977-01-01

The method applies to the reduction of the number of germs in infected products by combined treatment of the microorganisms with ionizing radiation and raised temperatures. In this process, at least part of the energy lost in the irradiation unit (e.g. electron linear accelerator or X-ray unit), which is not converted into ionizing radiation is used to heat the product. The invention can be used in the field of food and animal food treatment, for the sterilisation of medical equipment, or for the pasteurisation of waste water and fertilizers. (VJ) [de

Recovering hydrogen production performance of upflow anaerobic sludge blanket reactor (UASBR) fed with galactose via repeated heat treatment strategy.

Science.gov (United States)

Sivagurunathan, Periyasamy; Anburajan, Parthiban; Kumar, Gopalakrishnan; Park, Jong-Hun; Kim, Sang-Hyoun

2017-09-01

This study evaluated the effect of repeated heat treatment towards the enhancement of hydrogen fermentation from galactose in an upflow anaerobic sludge blanket reactor with the hydraulic retention time of 6h and the operation temperature of 37°C. The hydrogen production rate (HPR) and hydrogen yield (HY) gradually increased up to 9.1L/L/d and 1.1mol/mol galactose, respectively, until the 33rd day of operation. When heat treatment at 80°C for 30min was applied, hydrogen production performance was enhanced by 37% with the enrichment of hydrogen producing bacteria population. The HPR and HY were achieved at 12.5L/L/d and 1.5mol/mol hexose, respectively, during further 30 cycles of reactor operation. The repeated heat treatment would be a viable strategy to warrant reliable continuous hydrogen production using mixed culture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Developing the use of renewable heat

International Nuclear Information System (INIS)

Nifenecker, Herve

2013-01-01

The author reports a study in which he shows that the heat production by means of renewable energies is an efficient method to reach the objective of 23 per cent of renewable energies in the French final energy consumption. He browses the different techniques of renewable heat production (solar heat, wood-fuel, surface geothermal) and indicates the associated potential resources. He proposes a cost analysis which compares the use of gas and electricity with three techniques of production of renewable heat: solar heat to produce hot water, biomass combustion (more particularly wood), solar heat extracted with fuel cells. He also assesses tariffs and CO 2 emissions. Then, he elaborates a strategy to phase out fossil energies: a modification of the RT 2012 thermal regulation, to give up the purchase obligation for electricity produced by wind and photovoltaic energy, to extend the CSPE calculation basis, to put oil-fuel and gas boilers out of the market, to support the development of renewable heat production, to improve the competitiveness of the different techniques of renewable heat production. He finally gives a brief overview of industrial perspectives created by such a development of renewable heat

Sweat production during global heating and during isometric exercise in people with diabetes.

Science.gov (United States)

Petrofsky, Jerrold Scott; Lee, Scott; Patterson, Chris; Cole, Melissa; Stewart, Brian

2005-11-01

While sweat production in response to heat is impaired in people with diabetes, sweat production has not been examined during isometric exercise. Eight subjects with type 2 diabetes and 9 control subjects exerted a fatiguing isometric contraction of the handgrip muscles at a tension of 40% of the maximum voluntary strength (MVC) after exposure to a 32 deg C environment for 30 min. compared to 10 controls and 10 subjects with diabetes exposed to a 39 deg C environment. Sweat was impaired to all areas of the body during heat exposure in patients with diabetes under both environmental conditions. For example, on the chest, the average sweat rates after exposure to the 32 deg environment was 259.2 +/- 55.2 nanoliters/min in control subjects and 198.3 +/- 46.2 nanoliters/min for subjects with diabetes. Compared to the 32 deg C environment, control subjects increased sweat in all 4 areas proportionally more than subjects with diabetes. Sudomotor rhythm was present in sweat in control subjects at a rate of repetition of 11 and 50 seconds but almost absent in subjects with diabetes. During exercise, sweat rates slowly increased from the beginning to the end of the exercise. But the head of the subjects with diabetes showed hypersweating while the other areas showed diminished sweating compared to control subjects. Thus some of the impairment in sweating may be due to central mechanisms associated with heat sensitivity or in the hypothalamus and not to the sweat glands themselves.

New waste heat district heating system with combined heat and power based on absorption heat exchange cycle in China

International Nuclear Information System (INIS)

Sun Fangtian; Fu Lin; Zhang Shigang; Sun Jian

2012-01-01

A new waste heat district heating system with combined heat and power based on absorption heat exchange cycle (DHAC) was developed to increase the heating capacity of combined heat and power (CHP) through waste heat recovery, and enhance heat transmission capacity of the existing primary side district heating network through decreasing return water temperature by new type absorption heat exchanger (AHE). The DHAC system and a conventional district heating system based on CHP (CDH) were analyzed in terms of both thermodynamics and economics. Compared to CDH, the DHAC increased heating capacity by 31% and increased heat transmission capacity of the existing primary side district heating network by 75%. The results showed that the exergetic efficiency of DHAC was 10.41% higher and the product exergy monetary cost was 36.6¥/GJ less than a CHD. DHAC is an effective way to increase thermal utilization factor of CHP, and to reduce district heating cost. - Highlights: ► Absorption heat pumps are used to recover waste heat in CHP. ► Absorption heat exchanger can reduce exergy loss in the heat transfer process. ► New waste heat heating system (DHAC) can increase heating capacity of CHP by 31%. ► DHAC can enhance heat transmission capacity of the primary pipe network by 75%. ► DHAC system has the higher exergetic efficiency and the better economic benefit.

Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India

Directory of Open Access Journals (Sweden)

Manikandan Krishnamurthy

2017-03-01

Conclusion: Preliminary evidence shows that high heat exposures and heavy workload adversely affect the workers’ health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

Influence of fission product transport on delayed neutron precursors and decay heat sources in LMFBR accidents

International Nuclear Information System (INIS)

Apperson, C.E. Jr.

1981-01-01

A method is presented for studying the influence of fission product transpot on delayed neutron precursors and decay heat sources during Liquid Metal Fast Breeder Reactor (LMFBR) unprotected accidents. The model represents the LMFBR core as a closed homogeneous cell. Thermodynamic phase equilibrium theory is used to predict fission product mobility. Reactor kinetics behavior is analyzed by an extension of point kinetics theory. Group dependent delayed neutron precursor and decay heat source retention factors, which represent the fraction of each group retained in the fuel, are developed to link the kinetics and thermodynamics analysis. Application of the method to a highly simplified model of an unprotected loss-of-flow accident shows a time delay on the order of 10 ms is introduced in the predisassembly power history if fission product motion is considered when compared to the traditional transient solution. The post-transient influence of fission product transport calculated by the present model is a 24 percent reduction in the decay heat level in the fuel material which is similar to traditional approximations. Isotopes of the noble gases, Kr and Xe, and the elements I and Br are shown to be very mobile and are responsible for a major part of the observed effects. Isotopes of the elements Cs, Se, Rb, and Te were found to be moderately mobile and contribute to a lesser extent to the observed phenomena. These results obtained from the application of the described model confirm the initial hypothesis that sufficient fission product transport can occur to influence a transient. For these reasons, it is concluded that extension of this model into a multi-cell transient analysis code is warranted

Fission product retention in TRISO coated UO2 particle fuels subjected to HTR simulated core heating tests

International Nuclear Information System (INIS)

Baldwin, C.A.; Kania, M.J.

1991-01-01

Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbounded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 deg. C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 deg. C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 deg. C and above may exist. (author). 6 refs, 6 figs, 4 tabs

Fission product retention in TRISCO coated UO2 particle fuels subjected to HTR simulated core heating tests

International Nuclear Information System (INIS)

Baldwin, C.A.; Kania, M.J.

1990-11-01

Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 degree C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 degree C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 degree C and above may exist. 6 refs., 6 figs., 4 tabs

Cooked meat products made of coarsely ground pork: the main bacterial strains of bacterial flora, their heat resistance and effect on spoilage

Directory of Open Access Journals (Sweden)

Esko Petäjä

1993-09-01

Full Text Available This study was conducted to investigate the bacterial flora of the surface layer and the core of meat products made of coarsely ground pork at the moment of spoilage when stored at 7°C or 4°C. The dominating strains were isolated, their heat resistance was studied in APT-broth, on APT-agar and in coarsely ground cured pork, and their growth after heating and effect on spoilage were followed in coarsely ground cured pork. The first signs of spoilage appeared in the surface layer of the products. The strains were coccoid lactic acid bacteria with counts ranging from 3,5 to 7.8 log cfu (colony forming units/g. They survived only accidentally after heating for 15 minutes at 72°C in APT-broth. The core of the products contained only coccoid lactic acid bacteria or only pseudomonads or both as the main bacterial strains. The counts ranged from 2.6 to 6.0 log cfu/g. Most of the strains isolated from the core survived after heating for 30 minutes at 72°C in APT-broth in at least three tests out of six. The most noticeable result of the study was the occurence of heat-resistant pseudomonads in the core. It must be pointed out that all pseudomonads found survived after heating for 60 minutes at 72°C in APT-broth, and often after heating for 15 minutes at 72°C in coarsely ground cured pork (core 72°C. The cfu number of the two most heat-resistant streptococcus strains decreased only 1 log unit over 15 minutes at 72°C in coarsely ground cured pork. The numbers of inoculated pseudomonads decreased but those of streptococci rose by a maximum of 1 log unit when the experimental porks were kept at 4°C after heating. This indicates that streptococci and pseudomonads probably do not constitute a serious spoilage factor in cooked meat products, but spoilage is generally effected by bacteria which have contaminated the surface layer of the products after heat treatment.

Regenerative heat sources for heating networks

International Nuclear Information System (INIS)

Huenges, Ernst; Sperber, Evelyn; Eggers, Jan-Bleicke; Noll, Florian; Kallert, Anna Maria; Reuss, Manfred

2015-01-01

The ambitious goal, the German Federal Government has set itself, to reduce the emissions of greenhouse gases by 80% to 95% by the year 2050. As there are currently more than half of German energy consumption for the production of heat is required, big contributions to climate protection can be expected from this area if more renewable heat sources are used. Renewable heat sources such as bioenergy, solar thermal and geothermal energy in particular can be provided as compared to fossil fuels with significantly lower specific CO 2 emissions. Objectives in the heating market and scenarios for the transformation of the heat sector have been elaborated in the BMU Lead Study 2011. The main pillar of this scenario is the reduction of final energy consumption for heat by the energy-efficient renovation of existing buildings and further increasing demands on the energetic quality of new buildings. To cover the remaining energy demand, a focus is on the expansion of heating networks based on renewable energies. [de

Heat production, respiratory quotient, and methane loss subsequent to LPS challenge in beef heifers

Science.gov (United States)

Respiration calorimetry was used to measure energy utilization during an acute phase response (APR) to lipopolysaccharide (LPS). Eight Angus heifers (208 +/- 29.2 kg) were randomly assigned to one of two calorimeters in four 2-day periods for measurement of heat production (HP), methane (CH4), and r...

Modelling the behaviour of corrosion products in the primary heat transfer circuits of pressurised water reactors

International Nuclear Information System (INIS)

Rodliffe, R.S.; Polley, M.V.; Thornton, E.W.

1985-05-01

The redistribution of corrosion products from the primary circuit surfaces of a water reactor can result in increased flow resistance, poorer heat transfer performance, fuel failure and radioactive contamination of circuit surfaces. The environment is generally sufficiently well controlled to ensure that the first three effects are not limiting. The last effect is of particular importance since radioactive corrosion products are major contributors to shutdown fields and since it is necessary to ensure that the radiation exposure of personnel is as low as reasonably achievable. This review focusses attention on the principles which must form the basis for any mechanistic model describing the formation, transport and deposition of radioactive corrosion products. It is relevant to all water reactors in which the primary heat transfer medium is predominantly single-phase water and in which steam is generated in a secondary circuit, i.e. including CANDU pressurised heavy water reactors, Sovient VVERs, etc. (author)

Effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin.

Science.gov (United States)

Liu, Qian; Zhang, Min; Fang, Zhong-xiang; Rong, Xiao-hong

2014-09-01

The sterilization of vacuum-packaged Caixin (Brassica chinensis L.), which is a green-leafy vegetable and also a low-acid food, remains a difficult problem. In this study, effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin were investigated. Addition of ZnO nanoparticle suspension at 0.01-0.02 g kg(-1) reduced the number of bacterial colonies. The antibacterial activity was enhanced with the increased amount of ZnO nanoparticles. Microwave heating (915 and 2450 MHz) was used to sterilize Caixin samples. Samples had good product quality (better greenness, chroma and hue angle values, lower browning index and acceptable texture) and the lowest total colony number under the microwave heating condition of 400 W 150 s (2450 MHz). The best sterilization condition was observed under 2450 MHz microwave (400 W 150 s) heating combined with 0.02 g kg(-1) ZnO nanoparticle addition, which led to a total colony number of <1 log CFU g(-1) in Caixin samples within 7 days. © 2014 Society of Chemical Industry.

Water temperature, body mass and fasting heat production of pacu (Piaractus mesopotamicus).

Science.gov (United States)

Aguilar, Fredy A A; Cruz, Thaline M P DA; Mourão, Gerson B; Cyrino, José Eurico P

2017-01-01

Knowledge on fasting heat production (HEf) of fish is key to develop bioenergetics models thus improving feeding management of farmed species. The core of knowledge on HEf of farmed, neotropical fish is scarce. This study assessed the effect of body mass and water temperature on standard metabolism and fasting heat production of pacu, Piaractus mesopotamicus, an omnivore, Neotropical fresh water characin important for farming and fisheries industries all through South American continent. An automated, intermittent flow respirometry system was used to measure standard metabolic rate (SMR) of pacu (17 - 1,050 g) at five water temperatures: 19, 23, 26, 29 and 33 °C. Mass specific SMR increased with increasing water temperature but decreased as function of body mass. The allometric exponent for scaling HEf was 0.788, and lied in the range recorded for all studied warm-water fish. The recorded van't Hoff factor (Q10) for pacu (2.06) shows the species low response to temperature increases. The model HEf = 0.04643×W0.7882×T1.837 allows to predict HEf (kJ d-1) from body mass (W, kg) and water temperature (T, °C), and can be used in bioenergetical models for the species.

Water temperature, body mass and fasting heat production of pacu (Piaractus mesopotamicus

Directory of Open Access Journals (Sweden)

FREDY A.A. AGUILAR

Full Text Available ABSTRACT Knowledge on fasting heat production (HEf of fish is key to develop bioenergetics models thus improving feeding management of farmed species. The core of knowledge on HEf of farmed, neotropical fish is scarce. This study assessed the effect of body mass and water temperature on standard metabolism and fasting heat production of pacu, Piaractus mesopotamicus, an omnivore, Neotropical fresh water characin important for farming and fisheries industries all through South American continent. An automated, intermittent flow respirometry system was used to measure standard metabolic rate (SMR of pacu (17 - 1,050 g at five water temperatures: 19, 23, 26, 29 and 33 °C. Mass specific SMR increased with increasing water temperature but decreased as function of body mass. The allometric exponent for scaling HEf was 0.788, and lied in the range recorded for all studied warm-water fish. The recorded van't Hoff factor (Q10 for pacu (2.06 shows the species low response to temperature increases. The model HEf = 0.04643×W0.7882×T1.837 allows to predict HEf (kJ d-1 from body mass (W, kg and water temperature (T, °C, and can be used in bioenergetical models for the species.

The production of hydrogen-rich gas by wet sludge pyrolysis using waste heat from blast-furnace slag

International Nuclear Information System (INIS)

Luo, Siyi; Feng, Yu

2016-01-01

Blast furnace (BF) slag, a byproduct of steelmaking industry, contains a large amount of sensible heat and is composed of some metal oxides, which exhibits preferable catalytic performance in improving tar cracking and C_nH_m reforming. This paper presents a heat recovery system from the heat of BF slag, which generates hydrogen-rich gas via the endothermic reactions of sludge pyrolysis. The effects of various parameters including the slag temperature, the mass ratio of slag to sludge (B/S), particle size and feed moisture on product yields and gas characteristics were evaluated separately. It was found that the pyrolysis products distribution was significantly influenced by the BF slag temperature. The differences resulting from varying B/S practically disappear as higher temperature heat carrier is approached. The optimum feed moisture was in favour of sludge pyrolysis by getting char and tar participate in gasification reactions, improving gas yield and quality. BF slag as catalyst can greatly increase H_2 and CO contents of gas by improving tar degradation and reforming of biogas (CO_2 and CH_4). Decreasing the slag particles size was helpful to sludge primary pyrolysis to produce more light gases, less char and condensate, while its effects on gas compositions was not evident. - Highlights: • The sensible heat of molten slag was recovered and converted into combustible gas. • A novel rotary pyrolysis reactor using BF slag as heat carrier was presented. • The moisture in sludge was used as the gasification medium and hydrogen source.

Estimation of the heat generation in vitrified waste product and shield thickness of the cask for the transportation of vitrified waste product using Monte Carlo technique

International Nuclear Information System (INIS)

Deepa, A.K.; Jakhete, A.P.; Mehta, D.; Kaushik, C.P.

2011-01-01

High Level Liquid waste (HLW) generated during reprocessing of spent fuel contains most of the radioactivity present in the spent fuel resulting in the need for isolation and surveillance for extended period of time. Major components in HLW are the corrosion products, fission products such as 137 Cs, 90 Sr, 106 Ru, 144 Ce, 125 Sb etc, actinides and various chemicals used during reprocessing of spent fuel. Fresh HLW having an activity concentration of around 100Ci/l is to be vitrified into borosilicate glass and packed in canisters which are placed in S.S overpacks for better confinement. These overpacks contain around 0.7 Million Curies of activity. Characterisation of activity in HLW and activity profile of radionuclides for various cooling periods sets the base for the study. For transporting the vitrified waste product (VWP), two most important parameters is the shield thickness of the transportation cask and the heat generation in the waste product. This paper describes the methodology used in the estimation of lead thickness for the transportation cask using the Monte Carlo Technique. Heat generation due to decay of fission products results in the increase in temperature of the vitrified waste product during interim storage and disposal. Glass being the material, not having very high thermal conductivity, temperature difference between the canister and surrounding bears significance in view of the possibility of temperature based devitrification of VWP. The heat generation in the canister and the overpack containing vitrified glass is also estimated using MCNP. (author)

On the existence of another source of heat production for the earth and planets, and its connection with gravitomagnetism.

Science.gov (United States)

Elbeze, Alexandre Chaloum

2013-01-01

Recent revised estimates of the Earth's surface heat flux are in the order of 47 TW. Given that its internal radiogenic (mantle and crust) heat production is estimated to be around 20 TW, the Earth has a thermal deficit of around 27 TW. This article will try to show that the action of the gravitational field of the Sun on the rotating masses of the Earth is probably the source of another heat production in order of 54TW, which would satisfy the thermal balance of our celestial body and probably explain the reduced heat flow Qo. We reach this conclusion within the framework of gravitation implied by Einstein's special and general relativity theory (SR, GR). Our results show that it might possible, in principle, to calculate the heat generated by the action of the gravitational field of celestial bodies on the Earth and planets of the Solar System (a phenomenon that is different to that of the gravitational tidal effect from the Sun and the Moon). This result should help physicists to improve and develop new models of the Earth's heat balance, and suggests that contrary to cooling, the Earth is in a phase of thermal balance, or even reheating.

Advanced construction materials for thermo-chemical hydrogen production from VHTR process heat

International Nuclear Information System (INIS)

Kosmidou, Theodora; Haehner, Peter

2009-01-01

The (very) high temperature reactor concept ((V)HTR) is characterized by its potential for process heat applications. The production of hydrogen by means of thermo-chemical cycles is an appealing example, since it is more efficient than electrolysis due to the direct use of process heat. The sulfur-iodine cycle is one of the best studied processes for the production of hydrogen, and solar or nuclear energy can be used as a heating source for the high temperature reaction of this process. The chemical reactions involved in the cycle are: I 2 (l) + SO 2 (g) +2 H 2 O (l) → 2HI (l) + H 2 SO 4 (l) (70-120 deg. C); H 2 SO 4 (l) → H 2 O (l) + SO 2 (g) + 1/2 O 2 (g) (800-900 deg. C); 2HI (l) → I 2 (g) + H 2 (g) (300-450 deg. C) The high temperature decomposition of sulphuric acid, which is the most endothermic reaction, results in a very aggressive chemical environment which is why suitable materials for the decomposer heat exchanger have to be identified. The class of candidate materials for the decomposer is based on SiC. In the current study, SiC based materials were tested in order to determine the residual mechanical properties (flexural strength and bending modulus, interfacial strength of brazed joints), after exposure to an SO 2 rich environment, simulating the conditions in the hydrogen production plant. Brazed SiC specimens were tested after 20, 100, 500 and 1000 hrs exposure to SO 2 rich environment at 850 o C under atmospheric pressure. The gas composition in the corrosion rig was: 9.9 H 2 O, 12.25 SO 2 , 6.13 O 2 , balance N 2 (% mol). The characterization involved: weight change monitoring, SEM microstructural analysis and four-point bending tests after exposure. Most of the specimens gained weight due to the formation of a corrosion layer as observed in the SEM. The corrosion treatment also showed an effect on the mechanical properties. In the four-point bending tests performed at room temperature and at 850 deg. C, a decrease in bending modulus with

Distributed heat generation in a district heating system

OpenAIRE

Lennermo, Gunnar; Lauenberg, Patrick

2016-01-01

District heating (OH) systems need to be improved  regarding integration  of decentralised  heat generation. Micro production, prosumers and smart grids are terms becoming more and more common  in  connection  to  the  power  grid.  Concerning district  heating,  the  development  is slower, although improving. Today there are a number of such decentralised units for heat generation,  mainly  solar,  that have been partly evaluated.  Previous  studies  have shown  that there is a need to deve...

Internalising external costs of electricity and heat production in a municipal energy system

International Nuclear Information System (INIS)

Holmgren, Kristina; Amiri, Shahnaz

2007-01-01

Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU's ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument. Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST. The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods

Fuel cycle related parametric study considering long lived actinide production, decay heat and fuel cycle performances

International Nuclear Information System (INIS)

Raepsaet, X.; Damian, F.; Lenain, R.; Lecomte, M.

2001-01-01

One of the very attractive HTGR reactor characteristics is its highly versatile and flexible core that can fulfil a wide range of diverse fuel cycles. Based on a GTMHR-600 MWth reactor, analyses of several fuel cycles were carried out without taking into account common fuel particle performance limits (burnup, fast fluence, temperature). These values are, however, indicated in each case. Fuel derived from uranium, thorium and a wide variety of plutonium grades has been considered. Long-lived actinide production and total residual decay heat were evaluated for the various types of fuel. The results presented in this papers provide a comparison of the potential and limits of each fuel cycle and allow to define specific cycles offering lowest actinide production and residual heat associated with a long life cycle. (author)

The role of policy instruments for promoting combined heat and power production with low CO2 emissions in district heating systems

International Nuclear Information System (INIS)

Marbe, A.; Harvey, S.

2005-01-01

Policy instruments clearly influence the choice of production technologies and fuels in large energy systems, including district heating networks. Current Swedish policy instruments aim at promoting the use of biofuel in district heating systems, and at promoting electric power generation from renewable energy sources. However, there is increasing pressure to harmonize energy policy instruments within the EU. In addition, natural gas based combined cycle technology has emerged as the technology of choice in the power generation sector in the EU. This study aims at exploring the role of policy instruments for promoting the use of low CO 2 emissions fuels in high performance combined heat and power systems in the district heating sector. The paper presents the results of a case study for a Swedish district heating network where new large size natural gas combined cycle (NGCC) combined heat and power (CHP) is being built. Given the aim of current Swedish energy policy, it is assumed that it could be of interest in the future to integrate a biofuel gasifier to the CHP plant and co-fire the gasified biofuel in the gas turbine unit, thereby reducing usage of fossil fuel. The goals of the study are to evaluate which policy instruments promote construction of the planned NGCC CHP unit, the technical performance of an integrated biofuelled pressurized gasifier with or without dryer on plant site, and which combination of policy instruments promote integration of a biofuel gasifier to the planned CHP unit. The power plant simulation program GateCycle was used for plant performance evaluation. The results show that current Swedish energy policy instruments favour investing in the NGCC CHP unit. The corresponding cost of electricity (COE) from the NGCC CHP unit is estimated at 253 SEK MWh -1 , which is lower than the reference power price of 284 SEK MWh -1 . Investing in the NGCC CHP unit is also shown to be attractive if a CO 2 trading system is implemented. If the value of

Studies on heat transfer in agricultural products by far-infrared ray

International Nuclear Information System (INIS)

Liu, H.; Mohri, K.; Namba, K.

1998-01-01

Heat is transferred when the object being heated has temperature differences. In this research, the difference of two heating methods (far-infrared ray heating and hot wind heating) was analyzed. To compare their differences, the heat flux was measured by setting a heat flux meter beneath the surface of the object at different depths, then the heat conductivities and heat diffusion rates were analyzed. 1) Compared with hot wind, far-infrared ray heating has more heat flux before reaching a definite depth. 2) The heat conductivity and heat diffusion rates by hot wind heating have specific properties with special objects. The heat conductivity and heat diffusion rate of far-infrared heating are higher than those of hot wind heating. The differences are considered to be caused by far-infrared rays

Uncertainties in fission-product decay-heat calculations

Energy Technology Data Exchange (ETDEWEB)

Oyamatsu, K.; Ohta, H.; Miyazono, T.; Tasaka, K. [Nagoya Univ. (Japan)

1997-03-01

The present precision of the aggregate decay heat calculations is studied quantitatively for 50 fissioning systems. In this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library and those which are not available in this library are supplemented by a theoretical consideration. An approximate method is proposed to simplify the evaluation of the uncertainties in the aggregate decay heat calculations so that we can point out easily nuclei which cause large uncertainties in the calculated decay heat values. In this paper, we attempt to clarify the justification of the approximation which was not very clear at the early stage of the study. We find that the aggregate decay heat uncertainties for minor actinides such as Am and Cm isotopes are 3-5 times as large as those for {sup 235}U and {sup 239}Pu. The recommended values by Atomic Energy Society of Japan (AESJ) were given for 3 major fissioning systems, {sup 235}U(t), {sup 239}Pu(t) and {sup 238}U(f). The present results are consistent with the AESJ values for these systems although the two evaluations used different nuclear data libraries and approximations. Therefore, the present results can also be considered to supplement the uncertainty values for the remaining 17 fissioning systems in JNDC2, which were not treated in the AESJ evaluation. Furthermore, we attempt to list nuclear data which cause large uncertainties in decay heat calculations for the future revision of decay and yield data libraries. (author)

Perspectives of advanced thermal management in solar thermochemical syngas production using a counter-flow solid-solid heat exchanger

Science.gov (United States)

Falter, Christoph; Sizmann, Andreas; Pitz-Paal, Robert

2017-06-01

A modular reactor model is presented for the description of solar thermochemical syngas production involving counter-flow heat exchangers that recuperate heat from the solid phase. The development of the model is described including heat diffusion within the reactive material as it travels through the heat exchanger, which was previously identified to be a possibly limiting factor in heat exchanger design. Heat transfer within the reactive medium is described by conduction and radiation, where the former is modeled with the three-resistor model and the latter with the Rosseland diffusion approximation. The applicability of the model is shown by the analysis of heat exchanger efficiency for different material thicknesses and porosities in a system with 8 chambers and oxidation and reduction temperatures of 1000 K and 1800 K, respectively. Heat exchanger efficiency is found to rise strongly for a reduction of material thickness, as the element mass is reduced and a larger part of the elements takes part in the heat exchange process. An increase of porosity enhances radiation heat exchange but deteriorates conduction. The overall heat exchange in the material is improved for high temperatures in the heat exchanger, as radiation dominates the energy transfer. The model is shown to be a valuable tool for the development and analysis of solar thermochemical reactor concepts involving heat exchange from the solid phase.

Thermodynamic analysis and performance assessment of an integrated heat pump system for district heating applications

International Nuclear Information System (INIS)

Soltani, Reza; Dincer, Ibrahim; Rosen, Marc A.

2015-01-01

A Rankine cycle-driven heat pump system is modeled for district heating applications with superheated steam and hot water as products. Energy and exergy analyses are performed, followed by parametric studies to determine the effects of varying operating conditions and environmental parameters on the system performance. The district heating section is observed to be the most inefficient part of system, exhibiting a relative irreversibility of almost 65%, followed by the steam evaporator and the condenser, with relative irreversibilities of about 18% and 9%, respectively. The ambient temperature is observed to have a significant influence on the overall system exergy destruction. As the ambient temperature decreases, the system exergy efficiency increases. The electricity generated can increase the system exergy efficiency at the expense of a high refrigerant mass flow rate, mainly due to the fact that the available heat source is low quality waste heat. For instance, by adding 2 MW of excess electricity on top of the targeted 6 MW of product heat, the refrigerant mass flow rate increases from 12 kg/s (only heat) to 78 kg/s (heat and electricity), while the production of 8 MW of product heat (same total output, but in form of heat) requires a refrigerant mass flow rate of only 16 kg/s. - Highlights: • A new integrated heat pump system is developed for district heating applications. • An analysis and assessment study is undertaken through exergy analysis methodology. • A comparative efficiency evaluation is performed for practical applications. • A parametric study is conducted to investigate how varying operating conditions and state properties affect energy and exergy efficiencies.

Heat supply from nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Stach, V [Ustav Jaderneho Vyzkumu CSKAE, Rez (Czechoslovakia)

1978-05-01

The current state of world power production and consumption is assessed. Prognoses made for the years 1980 to 2000 show that nuclear energy should replace the major part of fossil fuels not only in the production of power but also in the production of heat. In this respect high-temperature reactors are highly prospective. The question is discussed of the technical and economic parameters of dual-purpose heat and power plants. It is, however, necessary to solve problems arising from the safe siting of nuclear heat and power plants and their environmental impacts. The economic benefits of combined power and heat production by such nuclear plants is evident.

Productivity Enhancement of Solar Still with PV Powered Heating Coil and Chamber Step-Wise Basin

Directory of Open Access Journals (Sweden)

Salah Abdallah

2018-03-01

Full Text Available There is a strong need to improve the productivity of single slope solar still. PV generator powered electrical heater and chamber step-wise design were introduced to the conventional solar still. An experimental study was performed to investigate the effect of adding the above mentioned modifications on the output parameters of the modified solar still. The inclusion of PV-powered heating coil and chamber step-wise design enhanced the productivity of distiller by up to 1098%.

Occurrence, distribution and contamination levels of heat-resistant moulds throughout the processing of pasteurized high-acid fruit products.

Science.gov (United States)

Santos, Juliana Lane Paixão Dos; Samapundo, Simbarashe; Biyikli, Ayse; Van Impe, Jan; Akkermans, Simen; Höfte, Monica; Abatih, Emmanuel Nji; Sant'Ana, Anderson S; Devlieghere, Frank

2018-05-19

Heat-resistant moulds (HRMs) are well known for their ability to survive pasteurization and spoil high-acid food products, which is of great concern for processors of fruit-based products worldwide. Whilst the majority of the studies on HRMs over the last decades have addressed their inactivation, few data are currently available regarding their contamination levels in fruit and fruit-based products. Thus, this study aimed to quantify and identify heat-resistant fungal ascospores from samples collected throughout the processing of pasteurized high-acid fruit products. In addition, an assessment on the effect of processing on the contamination levels of HRMs in these products was carried out. A total of 332 samples from 111 batches were analyzed from three processing plants (=three processing lines): strawberry puree (n = 88, Belgium), concentrated orange juice (n = 90, Brazil) and apple puree (n = 154, the Netherlands). HRMs were detected in 96.4% (107/111) of the batches and 59.3% (197/332) of the analyzed samples. HRMs were present in 90.9% of the samples from the strawberry puree processing line (1-215 ascospores/100 g), 46.7% of the samples from the orange juice processing line (1-200 ascospores/100 g) and 48.7% of samples from the apple puree processing line (1-84 ascospores/100 g). Despite the high occurrence, the majority (76.8%, 255/332) of the samples were either not contaminated or presented low levels of HRMs (processing had no statistically significant effect on the levels of HRMs (p > 0.05). On the contrary, a significant reduction (p levels was observed during the processing of apple puree. Twelve species were identified belonging to four genera - Byssochlamys, Aspergillus with Neosartorya-type ascospores, Talaromyces and Rasamsonia. N. fumigata (23.6%), N. fischeri (19.1%) and B. nivea (5.5%) were the predominant species in pasteurized products. The quantitative data (contamination levels of HRMs) were fitted to exponential

Skylab and solar exploration. [chromosphere-corona structure, energy production and heat transport processes

Science.gov (United States)

Von Puttkamer, J.

1973-01-01

Review of some of the findings concerning solar structure, energy production, and heat transport obtained with the aid of the manned Skylab space station observatory launched on May 14, 1973. Among the topics discussed are the observation of thermonuclear fusion processes which cannot be simulated on earth, the observation of short-wave solar radiation not visible to observers on earth, and the investigation of energy-transport processes occurring in the photosphere, chromosphere, and corona. An apparent paradox is noted in that the cooler chromosphere is heating the hotter corona, seemingly in defiance of the second law of thermodynamics, thus suggesting that a nonthermal mechanism underlies the energy transport. Understanding of this nonthermal mechanism is regarded as an indispensable prerequisite for future development of plasma systems for terrestrial applications.

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications

Energy Technology Data Exchange (ETDEWEB)

Lasfargues, Mathieu, E-mail: m.lasfargues@outlook.com; Bell, Andrew, E-mail: A.bell@leeds.ac.uk [University of Leeds, School of Chemical and Process Engineering (United Kingdom); Ding, Yulong, E-mail: y.ding@bham.ac.uk [University of Birmingham, School of Chemical Engineering (United Kingdom)

2016-06-15

In this study, TiO{sub 2} nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO{sub 4}) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

In situ production of titanium dioxide nanoparticles in molten salt phase for thermal energy storage and heat-transfer fluid applications

International Nuclear Information System (INIS)

Lasfargues, Mathieu; Bell, Andrew; Ding, Yulong

2016-01-01

In this study, TiO_2 nanoparticles (average particle size 16 nm) were successfully produced in molten salt phase and were showed to significantly enhance the specific heat capacity of a binary eutectic mixture of sodium and potassium nitrate (60/40) by 5.4 % at 390 °C and 7.5 % at 445 °C for 3.0 wt% of precursors used. The objective of this research was to develop a cost-effective alternate method of production which is potentially scalable, as current techniques utilized are not economically viable for large quantities. Enhancing the specific heat capacity of molten salt would promote more competitive pricing for electricity production by concentrating solar power plant. Here, a simple precursor (TiOSO_4) was added to a binary eutectic mixture of potassium and sodium nitrate, heated to 450 °C, and cooled to witness the production of nanoparticles.

Remote control systems for space heating. Product overview 2010 and recommendations - Final report; Fernsteuerungen fuer Raumheizungen. Produktuebersicht 2010 und Empfehlungen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Geilinger, E.; Bush, E. [Bush Energie GmbH, Felsberg (Switzerland); Venzin, T. [Hochschule fuer Technik und Wirtschaft (HTW) Chur, Chur (Switzerland); Nipkow, J. [Arena, Zuerich (Switzerland)

2010-09-15

Saving space heating energy by remote control: A remote-controlled space heating system allows a person to lower the room temperature in homes that go unoccupied for periods of time to the lowest temperature that's safe to keep the pipes from freezing while they're away. Comfort is guaranteed because the desired room temperature or mode can be activated in time before the guests arrive, via text message, phone or the internet. As most people simply leave unoccupied homes heated, the remote-controlled system saves up to 70% of heating energy when used actively. Market overview and product features: This report presents remote control devices that are currently available on the market. Their advantages and disadvantages are discussed as well as their technical features and function. Most of them are universal remote controls that have various uses, including temperature control. The report also discusses requirements that not all the examined products meet. Some lack an emergency power supply, the possibility for manual control or the ability to check the current temperature of the home from a remote location. Better planning for remote control: The critical issue proved not to be the remote control device itself, but the heating systems. Unfortunately, they often don't provide an option to be extended by remote control. We therefore call on the manufacturers to equip all new heating systems with options for remote control. It would also be helpful and desirable to provide information on the internet or in the technical documentation on how to connect a remote control device and which products are suitable - both for existing and new heating systems. If the system cannot be retrofitted, it should be described whether and how a central remote control with room thermostat can be installed. Improving communication: In this study, remote control and heating suppliers were interviewed as well as planners, installers and users of remote-controlled heating. Their responses

Heating and dehumidification in production greenhouses at northern latitudes

NARCIS (Netherlands)

Kempkes, F.; Zwart, De H.F.; Munoz, P.; Montero, J.I.; Baptista, F.J.; Giuffrida, F.; Gilli, Celine; Stepowska, Agnieszka; Stanghellini, C.

2017-01-01

The majority of greenhouses in northern latitudes are heated, in the winter mainly for temperature control and year round to control humidity. Heating is accepted by most organic regulations in different countries; if heating efficiently and the energy source is predominantly renewable energy,

Heating entrepreneur activity in 2003

International Nuclear Information System (INIS)

Nikkola, A.; Solmio, H.

2004-01-01

According to TTS Institute information, at the end of 2003 there were heating entrepreneurs responsible for fuel management and heat production in at least 212 heating plants in Finland. The number of operative plants increased by 36 from the previous year. At the end of 2003, the total boiler capacity for solid fuel in the plants managed by the heating entrepreneurs exceeded 100 megawatts. The average boiler capacity of the plants was 0.5 megawatts. Heating entrepreneur-ship was most common in west Finland, where 40 percent of the plants are located. There were some 94 heating plants managed by cooperatives or limited companies. Single entrepre neurs or entrepreneur networks consisting of several entrepreneurs were responsible for heat production in 117 plants. Heating entrepreneurs used approximately 290,000 loose cubic metres of forest chips, which is about seven percent of the volume used for heating and power plant energy production in 2003. In addition, the heating entrepreneurs used a total of 40,000 loose cubic metres of other wood fuel and an estimated 20,000 loose cubic metres of sod and milled peat. Municipalities are still the most important customer group for heating entrepreneurs. However, thenumber of private customers is growing. Industrial company, other private company or properly was the main customer already for every fourth plant established during 2003. (orig.)

Grate-firing of biomass for heat and power production

DEFF Research Database (Denmark)

Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

2008-01-01

bed on the grate, and the advanced secondary air supply (a real breakthrough in this technology) are highlighted for grate-firing systems. Amongst all the issues or problems associated with grate-fired boilers burning biomass, primary pollutant formation and control, deposition formation and corrosion......As a renewable and environmentally friendly energy source, biomass (i.e., any organic non-fossil fuel) and its utilization are gaining an increasingly important role worldwide Grate-firing is one of the main competing technologies in biomass combustion for heat and power production, because it can...... combustion mechanism, the recent breakthrough in the technology, the most pressing issues, the current research and development activities, and the critical future problems to be resolved. The grate assembly (the most characteristic element in grate-fired boilers), the key combustion mechanism in the fuel...

Optimisasi Suhu Pemanasan dan Kadar Air pada Produksi Pati Talas Kimpul Termodifikasi dengan Teknik Heat Moisture Treatment (HMT (Optimization of Heating Temperature and Moisture Content on the Production of Modified Cocoyam Starch Using Heat Moisture Treatment (HMT Technique

Directory of Open Access Journals (Sweden)

I Nengah Kencana Putra

2016-12-01

Full Text Available One of the physically starch modification technique is heat-moisture treatment (HMT. This technique can increase the resistance of starch to heat, mechanical treatment, and acid during processing.  This research aimed to find out the influence of heating temperature and moisture content in the modification process of cocoyam starch  with HMT techniques on the characteristic of product, and then to determine the optimum heating temperature and moisture content in the process. The research was designed with a complete randomized design (CRD with two factors factorial experiment.  The first factor was temperature of the heating consists of 3 levels namely 100 °C, 110 °C, and 120 °C. The second factor was the moisture content of starch which consists of 4 levels, namely 15 %, 20 %, 25 %, and 30 %. The results showed that the heating temperature and moisture content significantly affected water content, amylose content and swelling power of modified cocoyam starch product, but the treatment had no significant effect on the solubility of the product. HMT process was able to change the type of cocoyam starch from type B to type C. The optimum heating temperature and water content on modified cocoyam starch production process was 110 °C and 30 % respectively. Such treatment resulted in a modified cocoyam starch with moisture content of 6.50 %, 50,14 % amylose content, swelling power of 7.90, 0.0009% solubility, paste clarity of 96.310 % T, and was classified as a type C starch.   ABSTRAK Salah satu teknik modifikasi pati secara fisik adalah teknik Heat Moisture Treatment (HMT. Teknik ini dapat meningkatkan ketahanan pati terhadap panas, perlakuan mekanik, dan asam selama pengolahan. Penelitian ini bertujuan untuk mengetahui pengaruh suhu dan kadar air pada proses modifikasi pati talas kimpul dengan teknik HMT terhadap karakteristik produk, dan selanjutnya menentukan suhu dan kadar air yang optimal dalam proses tersebut. Penelitian ini dirancang

Evaluation of dry heat treatment of soft wheat flour for the production of high ratio cakes.

Science.gov (United States)

Keppler, S; Bakalis, S; Leadley, C E; Sahi, S S; Fryer, P J

2018-05-01

An accurate method to heat treat flour samples has been used to quantify the effects of heat treatment on flour functionality. A variety of analytical methods has been used such as oscillatory rheology, rheomixer, solvent retention capacity tests, and Rapid Visco Analysis (RVA) in water and in aqueous solutions of sucrose, lactic acid, and sodium carbonate. This work supports the hypothesis that heat treatment facilitates the swelling of starch granules at elevated temperature. Results furthermore indicated improved swelling ability and increased interactions of flour polymers (in particular arabinoxylans) of heat treated flour at ambient conditions. The significant denaturation of the proteins was indicated by a lack of gluten network formation after severe heat treatments as shown by rheomixer traces. Results of these analyses were used to develop a possible cake flour specification. A method was developed using response surfaces of heat treated flour samples in the RVA using i) water and ii) 50% sucrose solution. This can uniquely characterise the heat treatment a flour sample has received and to establish a cake flour specification. This approach might be useful for the characterisation of processed samples, rather than by baking cakes. Hence, it may no longer be needed to bake a cake after flour heat treatment to assess the suitability of the flour for high ratio cake production, but 2 types of RVA tests suffice. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

A Fresnel collector process heat experiment at Capitol Concrete Products

Science.gov (United States)

Hauger, J. S.

1981-01-01

An experiment is planned, conducted and evaluated to determine the feasibility of using a Power Kinetics' Fresnel concentrator to provide process heat in an industrial environment. The plant provides process steam at 50 to 60 psig to two autoclaves for curing masonry blocks. When steam is not required, the plant preheats hot water for later use. A second system is installed at the Jet Propulsion Laboratory parabolic dish test site for hardware validation and experiment control. Experiment design allows for the extrapolation of results to varying demands for steam and hot water, and includes a consideration of some socio-technical factors such as the impact on production scheduling of diurnal variations in energy availability.

Nuclear district heating. 1. Process heat reactors and transmission and distribution networks

International Nuclear Information System (INIS)

Caizergues, R.

1979-01-01

Three kinds of production station are considered: joint electricity and heat-producing stations, heat-producing stations with CAS reactors and heat-producing stations with Thermos reactors. The thermal energy supply possibilities of these stations, the cost price of this energy and the cost price per therm produced by the district heating source and conveyed to the user are studied [fr

Enhanced loss of fusion products during mode conversion heating in TFTR

International Nuclear Information System (INIS)

Darrow, D.S.; Majeski, R.; Fisch, N.J.; Heeter, R.F.; Herrmann, H.W.; Herrmann, M.C.; Zarnstorff, M.C.; Zweben, S.J.

1995-07-01

Ion Bernstein waves (IBWS) have been generated by mode conversion of ion cyclotron range of frequency (ICRF) fast waves in TFTR. The loss rate of fusion products in these discharges can be large, up to 10 times the first orbit loss rate. The losses are observed at the passing/trapped boundary, indicating that passing particles are being moved onto loss orbits either by increase of their v perpendicular due to the wave, by outward transport in minor radius, or both. The lost particles appear to be DD fusion produced tritons heated to ∼1.5 times their birth energy

Gas exchange, heat production and oxidation of fat in chicken embryos from a fast or slow growing line

DEFF Research Database (Denmark)

Chwalibog, André; Tauson, Anne-Helene; Ali, Abdalla

2007-01-01

The experiment comprised 48 chicken (Gallus gallus) embryos from a modern, fast growing line, Ross 308 (RO) and 48 from a slow growing line, Labresse (LA). The O(2) consumption and CO(2) production were measured in an open-air-circuit respiration unit, and heat production (HE) from embryos was ca...

Convective heat transfer behavior of the product slurry of the nitrate to ammonia and ceramic (NAC) process

International Nuclear Information System (INIS)

Muguercia, I.; Yang, G.; Ebadian, M.A.

1995-01-01

The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing liquid form low level radioactive waste (LLW). An experimental study has been conducted to measure the heat transfer properties of the NAC product slurry. The results indicate that the heat transfer coefficient for both concentration slurries is much higher than that of pure water, which may be due to the higher conductivity of the gibbsite powder. For the 20% concentration slurry, the heat transfer coefficient increased as the generalized Reynolds number and slurry temperature increased. The heat transfer coefficient of 40% is a function of the Reynolds number only. The test results also indicate that the thermal entrance region can be observed only when the generalized Reynolds number is smaller than 1,000. The correlation equation is also developed based on the experimental data in this paper

99Mo production using MoO3 pellets obtained by mechanical compression and heat treatment

International Nuclear Information System (INIS)

Rojas, Jorge; Mendoza, Pablo; Lopez, Alcides

2014-01-01

This paper shows the results of the MoO 3 pellets fabrication by mechanical compression and the heat treatment method (MCHT) in order to optimize the production of 99 Mo in the RACSO Nuclear Center. The effects of polyvinyl alcohol (PVA) as binder are assessed by heat treatment of pellets in air atmosphere, evaluating the elimination process with increasing temperature and solubility in 5N NaOH. The results show that the pellets fabrication technique is suitable because fulfills the required technical specifications, allows to irradiate 50 % more of 98 Mo mass and facilitate a safer radiological handling of the irradiated MoO 3 . (authors).

Heat Roadmap Europe

DEFF Research Database (Denmark)

Hansen, Kenneth; Connolly, David; Lund, Henrik

2015-01-01

The cost of heat savings in buildings increase as more heat savings are achieved due to the state of the building stock and hence, alternatives other than savings typically become more economically feasible at a certain level of heat reductions. It is important to identify when the cost of heat...... savings become more expensive than the cost of sustainable heat supply, so society does not overinvest in heat saving measures. This study first investigates the heat saving potentials for different countries in Europe, along with their associated costs, followed by a comparison with alternative ways...... of supplying sustainable heating. Different heat production options are included in terms of individual and community heating systems. Furthermore, the levelised cost of supplying sustainable heat is estimated for both a single technology and from an energy system perspective. The results are analysed...

Aging Impairs Whole-Body Heat Loss in Women under Both Dry and Humid Heat Stress.

Science.gov (United States)

Notley, Sean R; Poirier, Martin P; Hardcastle, Stephen G; Flouris, Andreas D; Boulay, Pierre; Sigal, Ronald J; Kenny, Glen P

2017-11-01

This study was designed to determine whether age-related impairments in whole-body heat loss, which are known to exist in dry heat, also occur in humid heat in women. To evaluate this possibility, 10 young (25 ± 4 yr) and 10 older (51 ± 7 yr) women matched for body surface area (young, 1.69 ± 0.11; older, 1.76 ± 0.14 m, P = 0.21) and peak oxygen consumption (V˙O2peak) (young, 38.6 ± 4.6; older, 34.8 ± 6.6 mL·kg·min, P = 0.15) performed four 15-min bouts of cycling at a fixed metabolic heat production rate (300 W; equivalent to ~45% V˙O2peak), each separated by a 15-min recovery, in dry (35°C, 20% relative humidity) and humid heat (35°C, 60% relative humidity). Total heat loss (evaporative ± dry heat exchange) and metabolic heat production were measured using direct and indirect calorimetry, respectively. Body heat storage was measured as the temporal summation of heat production and loss. Total heat loss was lower in humid conditions compared with dry conditions during all exercise bouts in both groups (all P body heat storage in young and older women, respectively (both P body heat storage was 29% and 16% greater in older women compared with young women in dry and humid conditions, respectively (both P < 0.05). Increasing ambient humidity reduces heat loss capacity in young and older women. However, older women display impaired heat loss relative to young women in both dry and humid heat, and may therefore be at greater risk of heat-related injury during light-to-moderate activity.

Allocating resources and products in multi-hybrid multi-cogeneration: What fractions of heat and power are renewable in hybrid fossil-solar CHP?

International Nuclear Information System (INIS)

Beretta, Gian Paolo; Iora, Paolo; Ghoniem, Ahmed F.

2014-01-01

A general method for the allocation of resources and products in multi-resource/multi-product facilities is developed with particular reference to the important two-resource/two-product case of hybrid fossil and solar/heat and power cogeneration. For a realistic case study, we show how the method allows to assess what fractions of the power and heat should be considered as produced from the solar resource and hence identified as renewable. In the present scenario where the hybridization of fossil power plants by solar-integration is gaining increasing attention, such assessment is of great importance in the fair and balanced development of local energy policies based on granting incentives to renewables resources. The paper extends to the case of two-resource/two-product hybrid cogeneration, as well as to general multi-resource/multi-generation, three of the allocation methods already available for single-resource/two-product cogeneration and for two-resource/single-product hybrid facilities, namely, the ExRR (Exergy-based Reversible-Reference) method, the SRSPR (Single Resource Separate Production Reference) method, and the STALPR (Self-Tuned-Average-Local-Productions-Reference) method. For the case study considered we show that, unless the SRSPR reference efficiencies are constantly updated, the differences between the STALPR and SRSPR methods become important as hybrid and cogeneration plants take up large shares of the local energy production portfolio. - Highlights: • How much of the heat and power in hybrid solar-fossil cogeneration are renewable? • We define and compare three allocation methods for hybrid cogeneration. • Classical and exergy allocation are based on prescribed reference efficiencies. • Adaptive allocation is based on the actual average efficiencies in the local area. • Differences among methods grow as hybrid CHP (heat and power cogeneration) gains large market fractions

Inventory of future power and heat production technologies; Inventering av framtidens el- och vaermeproduktionstekniker

Energy Technology Data Exchange (ETDEWEB)

Ekstroem, Clas (Vattenfall Research and Development AB, Stockholm (Sweden))

2008-12-15

's Water Framework Directive. Combined heat and power with a steam cycle is currently the most cost-effective alternative for biofuel based power production, and it also provides optimal utilization of fuel. The potential here is restricted mainly by the amount of available district heating demands. Gasification with gas turbines or gas engines ensures higher electricity efficiency for plants up to 50 MW, although costs are currently high. Wind power has become competitive owing to fast international expansion, although only on the strength of effective climate-related control measures and measures favouring renewable energy production. Its potential is restricted by the quantities that can be integrated into the electricity network, given that production is reliant on wind conditions. The possibility of storing electricity/energy could increase its usability. Wave power is a promising future alternative, although currently at an early stage of development. Its potential is restricted by the quantities that can be integrated into the electricity network, given that production is entirely reliant on waves. Combined plants with combined heat and power or district heating improve the overall utilization of fuel. Upgrading solid biofuels to pellets is currently a competitive option, and torrefication could prove an interesting option should there be a demand for prolonged storing ability and improved grindability. Pyrolysis oil can be burned in simple plants, and would also enable a cost-effective use of 'problematic' biofuels. Infrastructure and handling must however be adapted to the fact that pyrolysis oil is corrosive and unstable for storing. The competitiveness of all biofuel based automotive fuel alternatives studied pre-supposes that future control measures within the transport sector are equally effective as those currently in place. Under current conditions biogas is a competitive alternative to petrol, but its potential is curbed by the restricted

Study of heat transfer parameters on rhodium target for 103Pd production

International Nuclear Information System (INIS)

Sadeghi, M.; Tenreiro, C.; Van den Winkel, P.

2009-01-01

The efficiency of cooling and the particle beam characteristics are important when high beam current irradiations are intended for production of radionuclides. The efficiency of cooling is determined by both the target carrier geometry and the flow rate of coolant, while the beam characteristics deal with the current density distribution on the irradiated surface area. Heat transfer on rhodium target to produce 103 Pd via the 103 Rh(p,n) 103 Pd reaction was investigated and the beam current was obtained more than 500 μA. (authors)

The improved heat integration of cement production under limited process conditions: A case study for Croatia

International Nuclear Information System (INIS)

Boldyryev, Stanislav; Mikulčić, Hrvoje; Mohorović, Zoran; Vujanović, Milan; Krajačić, Goran; Duić, Neven

2016-01-01

Given that cement is the most widely used material for housing and modern infrastructure needs, this paper analyses the energy efficiency of the cement manufacturing processes for a particular cement plant. The cement industry is one of the largest consumers of carbon-containing primary energy sources and one of the primary polluters of the environment, emitting approximately 5% of global pollution. Energy consumption represents the largest part of the production cost for cement factories and has a significant influence on product prices. Given that it is realised in modern society that infrastructural projects lead to a higher level of economy and sustainability for countries, reducing the production cost in the cement industry is a very important problem. The authors analysed the energy consumption of a particular cement factory in Croatia to determine the minimum energy targets of production and proposed pathways to improve energy efficiency. The Process Integration approach was used in this study. Nevertheless, the features of the cement factory forced the research to update its methodological steps to propose real pathways for a retrofit project with the aim of achieving the optimal minimum temperature difference between process streams. There are various streams, including those that contain solid particles, gas and air streams, and streams, that should be cooled down rapidly; these facts become more complicated by the special construction of the process equipment, which causes heat transfer between some streams to be impossible. The main objective of this paper is to determine the potential of real energy savings and propose a solution for a new concept of heat exchanger network (HEN) that avoids the process traps and provides a feasible retrofit. The maximum heat recovery of that production of a particular type of cement was determined and improved when a HEN was built. The authors conclude that the energy consumption of the cement factory can be reduced by

High efficiency bio-hydrogen production from glucose revealed in an inoculum of heat-pretreated landfill leachate sludge

International Nuclear Information System (INIS)

Wong, Y.M.; Juan, J.C.; Ting, Adeline; Wu, T.Y.

2014-01-01

Bio-hydrogen is a promising sustainable energy to replace fossil fuels. This study investigated bio-H 2 production from the inoculum of heat-pretreated landfill leachate sludge using glucose as model substrate. The seed sludge pretreated at 65 °C showed the highest amount of H 2 at the optimum condition of pH 6 and 37 °C. The maximum H 2 yield estimated by the modified Gompertz model was 6.43 mol H 2 /mol glucose. The high efficient of H 2 production is thermodynamically feasible with the Gibbs free energy of −34 kJ/mol. This study reveals that pretreated landfill leachate sludge has considerable potential for H 2 production. - Highlights: • Heat retreated landfill leachate sludge revealed high efficient H 2 production. • High efficient H 2 yield, 6.4 mol H 2 /mol glucose. • The synergisms between H 2 -producing bacteria may responsible for the high H 2 yield. • High H 2 yield is thermodynamically feasible with Gibbs free energy of −34 kJ/mol

Dynamics of nutrient utilization, heat production, and body composition in broiler breeder hens during egg production.

Science.gov (United States)

Caldas, Justina V; Hilton, Katie; Boonsinchai, Nirun; England, Judith A; Mauromoustakos, Andy; Coon, Craig N

2018-04-24

Changes in heat production (HP) and body composition (BC) in modern broiler breeders can provide means to understand nutrient utilization. Twelve Cobb 500 breeders were evaluated 10 times from 26 to 59 wk of age. The same wired caged breeders were moved to respiratory chambers connected to an indirect calorimetry to obtain oxygen consumption (VO2) and carbon dioxide production (VCO2), HP, and respiratory exchange ratio (RER). The same hens were evaluated for BC using a dual X-ray absorptiometry (DEXA). Data were analyzed during light (16 h) and dark (8 h) period using a mixed model to evaluate calorimetry parameters, a factorial design 2 × 10 for normalized calorimetry parameters, and Complete Randomized Design (CRD)-one way ANOVA for BC. Means were separated by Tukey-Honest Significant difference (HSD). HP increased with age (d) in 0.152 kcal/d, VO2 and VCO2 were 0.031 and 0.024 L/d per each increase in age (d), respectively. In the light period, hens consumed +17.4 L/d VO2 and produced +18.9 L/d VCO2 (P production. Lean body mass ranged from 642 to 783 g/kg during the whole study reaching the lowest at 37 and 50 wk and the highest at 26 to 33 wk (P production is reduced, and HP increased at 54 and 59 wk (P lean mass structure. Broiler breeders change nutrient fuel use during egg production. Indirect calorimetry and DEXA can be used to pursue further feed strategies to maximize egg production and maintain a healthy breeder.

Remote control systems for space heating. Product overview 2010 and recommendations - Final report; Fernsteuerungen fuer Raumheizungen. Produktuebersicht 2010 und Empfehlungen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Geilinger, E.; Bush, E. [Bush Energie GmbH, Felsberg (Switzerland); Venzin, T. [Hochschule fuer Technik und Wirtschaft (HTW) Chur, Chur (Switzerland); Nipkow, J. [Arena, Zuerich (Switzerland)

2010-09-15

Saving space heating energy by remote control: A remote-controlled space heating system allows a person to lower the room temperature in homes that go unoccupied for periods of time to the lowest temperature that's safe to keep the pipes from freezing while they're away. Comfort is guaranteed because the desired room temperature or mode can be activated in time before the guests arrive, via text message, phone or the internet. As most people simply leave unoccupied homes heated, the remote-controlled system saves up to 70% of heating energy when used actively. Market overview and product features: This report presents remote control devices that are currently available on the market. Their advantages and disadvantages are discussed as well as their technical features and function. Most of them are universal remote controls that have various uses, including temperature control. The report also discusses requirements that not all the examined products meet. Some lack an emergency power supply, the possibility for manual control or the ability to check the current temperature of the home from a remote location. Better planning for remote control: The critical issue proved not to be the remote control device itself, but the heating systems. Unfortunately, they often don't provide an option to be extended by remote control. We therefore call on the manufacturers to equip all new heating systems with options for remote control. It would also be helpful and desirable to provide information on the internet or in the technical documentation on how to connect a remote control device and which products are suitable - both for existing and new heating systems. If the system cannot be retrofitted, it should be described whether and how a central remote control with room thermostat can be installed. Improving communication: In this study, remote control and heating suppliers were interviewed as well as planners, installers and users of remote-controlled heating

Systematic losses of outdoor production from heat stress and climate change

Science.gov (United States)

Buzan, J. R.; Huber, M.

2017-12-01

Heat stress impacts humans today with heat waves, worker reductions, and health issues. Here we show novel results in labor productivity for outdoor work due to global warming. We use the HumanIndexMod to calculate 4x daily values of Simplified Wet Bulb Globe Temperature index (sWBGT) from the CMIP5 archive normalized by global mean surface temperature changes. Previous work shows that scaling of sWBGT is robust across the CMIP5 archive. We calculate total annual outdoor labor capacity from our scaled sWBGT results. Our results show modern day losses due to heat stress impacting outdoor work for low latitudes (and parts of Eastern China and the Southern United States). At 2°C of climate change, up to 20% losses to total capacity impact Midwestern United States, while the Southern United States suffers >20% losses. Western Coastal Africa suffers annual losses at >80%, along with the Amazon Basin and the greater South East Asia region. India suffers losses >50% annually. At +5°C, the estimated mean global change by 2100, the Equatorial region (Northern Australia and Northern Bolivia to Western Coastal Africa and Southern India) has complete cessation of annual outdoor work. The Midwest United States suffers losses up to 30%, and the Gulf of Mexico suffers losses >50%. Our results imply that small changes in global mean surface temperature (2°C) will lead to crippling losses to outdoor work annually, and ≥5°C losses will lead to cessation of labor for more than half the world's population.

Solar radiation during rewarming from torpor in elephant shrews: supplementation or substitution of endogenous heat production?

Science.gov (United States)

Thompson, Michelle L; Mzilikazi, Nomakwezi; Bennett, Nigel C; McKechnie, Andrew E

2015-01-01

Many small mammals bask in the sun during rewarming from heterothermy, but the implications of this behaviour for their energy balance remain little understood. Specifically, it remains unclear whether solar radiation supplements endogenous metabolic thermogenesis (i.e., rewarming occurs through the additive effects of internally-produced and external heat), or whether solar radiation reduces the energy required to rewarm by substituting (i.e, replacing) metabolic heat production. To address this question, we examined patterns of torpor and rewarming rates in eastern rock elephant shrews (Elephantulus myurus) housed in outdoor cages with access to either natural levels of solar radiation or levels that were experimentally reduced by means of shade cloth. We also tested whether acclimation to solar radiation availability was manifested via phenotypic flexibility in basal metabolic rate (BMR), non-shivering thermogenesis (NST) capacity and/or summit metabolism (Msum). Rewarming rates varied significantly among treatments, with elephant shrews experiencing natural solar radiation levels rewarming faster than conspecifics experiencing solar radiation levels equivalent to approximately 20% or 40% of natural levels. BMR differed significantly between individuals experiencing natural levels of solar radiation and conspecifics experiencing approximately 20% of natural levels, but no between-treatment difference was evident for NST capacity or Msum. The positive relationship between solar radiation availability and rewarming rate, together with the absence of acclimation in maximum non-shivering and total heat production capacities, suggests that under the conditions of this study solar radiation supplemented rather than substituted metabolic thermogenesis as a source of heat during rewarming from heterothermy.

2D heat and mass transfer modeling of methane steam reforming for hydrogen production in a compact reformer

International Nuclear Information System (INIS)

Ni Meng

2013-01-01

Highlights: ► A heat and mass transfer model is developed for a compact reformer. ► Hydrogen production from methane steam reforming is simulated. ► Increasing temperature greatly increases the reaction rates at the inlet. ► Temperature in the downstream is increased at higher rate of heat supply. ► Larger permeability enhances gas flow and reaction rates in the catalyst layer. - Abstract: Compact reformers (CRs) are promising devices for efficient fuel processing. In CRs, a thin solid plate is sandwiched between two catalyst layers to enable efficient heat transfer from combustion duct to the reforming duct for fuel processing. In this study, a 2D heat and mass transfer model is developed to investigate the fundamental transport phenomenon and chemical reaction kinetics in a CR for hydrogen production by methane steam reforming (MSR). Both MSR reaction and water gas shift reaction (WGSR) are considered in the numerical model. Parametric simulations are performed to examine the effects of various structural/operating parameters, such as pore size, permeability, gas velocity, temperature, and rate of heat supply on the reformer performance. It is found that the reaction rates of MSR and WGSR are the highest at the inlet but decrease significantly along the reformer. Increasing the operating temperature raises the reaction rates at the inlet but shows very small influence in the downstream. For comparison, increasing the rate of heat supply raises the reaction rates in the downstream due to increased temperature. A high gas velocity and permeability facilitates gas transport in the porous structure thus enhances reaction rates in the downstream of the reformer.

Ten-minute umbilical cord occlusion markedly reduces cerebral blood flow and heat production in fetal sheep.

NARCIS (Netherlands)

Lotgering, F.K.; Bishai, J.M.; Struijk, P.C.; Blood, A.B.; Hunter, C.J.; Power, G.G.; Longo, L.D.

2003-01-01

OBJECTIVE: The study was undertaken to determine to what extent a 10-minute total umbilical cord occlusion affects autoregulation of cerebral blood flow and cerebral heat production in the fetus. STUDY DESIGN: In seven chronically catheterized late-gestation fetal sheep (127-131 days' gestation), we

Genomic Selection Improves Heat Tolerance in Dairy Cattle

Science.gov (United States)

Garner, J. B.; Douglas, M. L.; Williams, S. R. O; Wales, W. J.; Marett, L. C.; Nguyen, T. T. T.; Reich, C. M.; Hayes, B. J.

2016-01-01

Dairy products are a key source of valuable proteins and fats for many millions of people worldwide. Dairy cattle are highly susceptible to heat-stress induced decline in milk production, and as the frequency and duration of heat-stress events increases, the long term security of nutrition from dairy products is threatened. Identification of dairy cattle more tolerant of heat stress conditions would be an important progression towards breeding better adapted dairy herds to future climates. Breeding for heat tolerance could be accelerated with genomic selection, using genome wide DNA markers that predict tolerance to heat stress. Here we demonstrate the value of genomic predictions for heat tolerance in cohorts of Holstein cows predicted to be heat tolerant and heat susceptible using controlled-climate chambers simulating a moderate heatwave event. Not only was the heat challenge stimulated decline in milk production less in cows genomically predicted to be heat-tolerant, physiological indicators such as rectal and intra-vaginal temperatures had reduced increases over the 4 day heat challenge. This demonstrates that genomic selection for heat tolerance in dairy cattle is a step towards securing a valuable source of nutrition and improving animal welfare facing a future with predicted increases in heat stress events. PMID:27682591

Heat production / host rock compatibility; Waermeentwicklung / Gesteinsvertraeglichkeit

Energy Technology Data Exchange (ETDEWEB)

Meleshyn, A.; Weyand, T.; Bracke, G.; Kull, H.; Wieczorek, K.

2016-05-15

For the final high-level radioactive waste repository potential host rock formations are either rock salt or clays (Kristallin). Heat generating waste (decay heat of the radioactive materials) can be absorbed by the host rock. The effect of temperature increase on the thermal conductivity, the thermal expansion and the mechanical properties of salt, Kristallin, clays and argilliferous geotechnical barriers are described. Further issues of the report are the mineralogical behavior, phase transformations, hydrochemistry, microbial processes, gas formation, thermochemical processes and gas ingress. Recommendations for further research are summarized.

Preliminary safety analysis of a PBMR supplying process heat to a co-located ethylene production plant

International Nuclear Information System (INIS)

Scarlat, Raluca O.; Cisneros, Anselmo T.; Koutchesfahani, Tawni; Hong, Rada; Peterson, Per F.

2012-01-01

This paper considers the safety analysis and licensing approach for co-locating a pebble bed modular reactor (PBMR) to provide process heat to an ethylene production unit. The PBMR is an advanced nuclear reactor design that provides 400 MW of thermal energy. Ethylene production is an energy intensive process that utilizes large gas furnaces to provide the heat for the process. Coupling a PBMR with an ethylene production plant would open a new market for nuclear power, and would provide the chemical industry with a cleaner power source, helping to achieve the Clean Air Act standards, and eliminating the 0.5 ton of CO 2 emissions per ton of produced ethylene. Our analysis uses the Chevron Phillips chemical plant in Sweeney, TX as a prototypical site. The plant has four ethylene production trains, with a total power consumption of 2.4 GW, for an ethylene output of 3.7 million tons per year, 4% of the global ethylene production capacity. This paper proposes replacement of the gas furnaces by low-emission PBMR modules, and presents the safety concerns and risk mitigation and management options for this coupled system. Two coupling design options are proposed, and the necessary changes to the design basis events and severe accidents for the PBMR licensing application are discussed. A joint effort between the chemical and the nuclear entities to optimize the coupling design, establish preventive maintenance procedures, and develop emergency response plans for both of the units is recommended.

Preliminary safety analysis of a PBMR supplying process heat to a co-located ethylene production plant

Energy Technology Data Exchange (ETDEWEB)

Scarlat, Raluca O., E-mail: rscarlat@nuc.berkeley.edu [University of California Berkeley, Nuclear Engineering, 4118 Etcheverry Hall, Berkeley, CA 94720 (United States); Cisneros, Anselmo T. [University of California Berkeley, Nuclear Engineering, 4118 Etcheverry Hall, Berkeley, CA 94720 (United States); Koutchesfahani, Tawni [University of California, Chemical and Biomolecular Engineering, 201 Gilman Hall, Berkeley, CA 94720 (United States); Hong, Rada; Peterson, Per F. [University of California Berkeley, Nuclear Engineering, 4118 Etcheverry Hall, Berkeley, CA 94720 (United States)

2012-10-15

This paper considers the safety analysis and licensing approach for co-locating a pebble bed modular reactor (PBMR) to provide process heat to an ethylene production unit. The PBMR is an advanced nuclear reactor design that provides 400 MW of thermal energy. Ethylene production is an energy intensive process that utilizes large gas furnaces to provide the heat for the process. Coupling a PBMR with an ethylene production plant would open a new market for nuclear power, and would provide the chemical industry with a cleaner power source, helping to achieve the Clean Air Act standards, and eliminating the 0.5 ton of CO{sub 2} emissions per ton of produced ethylene. Our analysis uses the Chevron Phillips chemical plant in Sweeney, TX as a prototypical site. The plant has four ethylene production trains, with a total power consumption of 2.4 GW, for an ethylene output of 3.7 million tons per year, 4% of the global ethylene production capacity. This paper proposes replacement of the gas furnaces by low-emission PBMR modules, and presents the safety concerns and risk mitigation and management options for this coupled system. Two coupling design options are proposed, and the necessary changes to the design basis events and severe accidents for the PBMR licensing application are discussed. A joint effort between the chemical and the nuclear entities to optimize the coupling design, establish preventive maintenance procedures, and develop emergency response plans for both of the units is recommended.

Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

International Nuclear Information System (INIS)

Åberg, M.; Henning, D.

2011-01-01

The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO 2 emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO 2 emissions in the analysed DH system. - Highlights: ► A MODEST optimisation model of the Linköping district heating system is used. ► The impact of heat demand reduction on heat and electricity production is examined. ► Model results show that heat demand reductions decrease heat-only production. ► Local and global CO 2 emissions are reduced. ► The system electricity-to-heat output increases for reduced heat demand up to 30%.

Radiation and combined heat transfer in channels

International Nuclear Information System (INIS)

Tamonis, M.

1986-01-01

This book presents numerical methods of calculation of radiative and combined heat transfer in channel flows of radiating as well as nonradiating media. Results obtained in calculations for flow conditions of combustion products from organic fuel products are given and methods used in determining the spectral optical properties of molecular gases are analyzed. The book presents applications of heat transfer in solving problems. Topic covered are as follows: optical properties of molecular gases; transfer equations for combined heat transfer; experimental technique; convective heat transfer in heated gas flows; radiative heat transfer in gaseous media; combined heat transfer; and radiative and combined heat transfer in applied problems

Influence of salicylic and succinic acids on antioxidant enzymes activity, heat resistance and productivity of Panicum miliaceum L.

Directory of Open Access Journals (Sweden)

Miroshnichenko N.N.

2011-05-01

Full Text Available The influence of treatment of millet (Panicum miliaceum L. seeds with the solutions of salicylic and succinic acids on the heat resistance of plantlets and activity of antioxidant enzymes – superoxide dismutase (SOD, catalase and peroxidase – in them have been investigated. In the micro-field experiment the influence of these acids on the millet yield was estimated. The action of salicylic (10 μM and succinic (1 mM acids caused the increase of plantlets resistance to the damaging heating that expressed in the rise of relative quantity of survived plantlets in 5 days after heating at the temperature of 47°С and in the reduced content of lipid peroxidation product malonic dialdehyde during the poststress period. The increase of activity of SOD, catalase and peroxidase took place in millet plantlets under the influence of salicylic and succinic acids. The increase of productivity of millet grain under the action of salicylic and succinic acids on 13,3-52,0 and 6,4-38,8% respectively depending on weather conditions in the field experiments was noted.

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

Science.gov (United States)

Sibille, Laurent; Dominguez, Jesus A.

2012-01-01

The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a Joule-heated (sometimes called 'self-heating') reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. Solutions obtained by multiphysics modeling allow the identification of the critical dimensions of concept reactors.

Assessment of tobacco heating product THP1.0. Part 4: Characterisation of indoor air quality and odour.

Science.gov (United States)

Forster, Mark; McAughey, John; Prasad, Krishna; Mavropoulou, Eleni; Proctor, Christopher

2018-03-01

The tobacco heating product THP1.0, which heats but does not burn tobacco, was tested as part of a modified-risk tobacco product assessment framework for its impacts on indoor air quality and residual tobacco smoke odour. THP1.0 heats the tobacco to less than 240 °C ± 5 °C during puffs. An environmentally controlled room was used to simulate ventilation conditions corresponding to residential, office and hospitality environments. An analysis of known tobacco smoke constituents, included CO, CO 2 , NO, NO 2 , nicotine, glycerol, 3-ethenyl pyridine, sixteen polycyclic aromatic hydrocarbons, eight volatile organic compounds, four carbonyls, four tobacco-specific nitrosamines and total aerosol particulate matter. Significant emissions reductions in comparison to conventional cigarettes were measured for THP1.0. Levels of nicotine, acetaldehyde, formaldehyde and particulate matter emitted from THP1.0 exceeded ambient air measurements, but were more than 90% reduced relative to cigarette smoke emissions within the laboratory conditions defined Residual tobacco smoke odour was assessed by trained sensory panels after exposure of cloth, hair and skin to both mainstream and environmental emissions from the test products. Residual tobacco smoke odour was significantly lower from THP1.0 than from a conventional cigarette. These data show that using THP1.0 has the potential to result in considerably reduced environmental emissions that affect indoor air quality relative to conventional cigarettes. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Electric heating of a unit for uranium trioxide production

International Nuclear Information System (INIS)

Faron, R.; Striff, A.

1985-01-01

Ammonium diuranate U 2 O 7 (NH 4 ) 2 containing about 50% of water is dried and transformed by calcination in uranium trioxide UO 3 . Drying and calcination was obtained by air heated by two burners using domestic fuel. In 1984 the plant was transformed for utilization of electric heating improving maintenance cost, decreasing heat losses and by energy saving the payback period on investment is of 2.6 years [fr

Heat Production by the Denitrifying Bacterium Pseudomonas fluorescens and the Dissimilatory Ammonium-Producing Bacterium Pseudomonas putrefaciens during Anaerobic Growth with Nitrate as the Electron Acceptor

OpenAIRE

Samuelsson, M.-O.; Cadez, P.; Gustafsson, L.

1988-01-01

The heat production rate and the simultaneous nitrate consumption and production and consumption of nitrite and nitrous oxide were monitored during the anaerobic growth of two types of dissimilatory nitrate reducers. Pseudomonas fluorescens, a denitrifier, consumed nitrate and accumulated small amounts of nitrite or nitrous oxide. The heat production rate increased steadily during the course of nitrate consumption and decreased rapidly concomitant with the depletion of the electron acceptors....

Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

Science.gov (United States)

Al-Sulaiman, Fahad A.; Dincer, Ibrahim; Hamdullahpur, Feridun

The study examines a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis. The system consists of an SOFC, an ORC, a heat exchanger and a single-effect absorption chiller. The system is modeled to produce a net electricity of around 500 kW. The study reveals that there is 3-25% gain on exergy efficiency when trigeneration is used compared with the power cycle only. Also, the study shows that as the current density of the SOFC increases, the exergy efficiencies of power cycle, cooling cogeneration, heating cogeneration and trigeneration decreases. In addition, it was shown that the effect of changing the turbine inlet pressure and ORC pump inlet temperature are insignificant on the exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration. Also, the study reveals that the significant sources of exergy destruction are the ORC evaporator, air heat exchanger at the SOFC inlet and heating process heat exchanger.

Urban district heating using nuclear heat - a survey

International Nuclear Information System (INIS)

Beresovski, T.; Oliker, I.

1979-01-01

The use of heat from nuclear power plants is of great interest in connection with projected future expansions of large urban district heating systems. Oil price escalation and air pollution from increased burning of fossil fuels are substantial incentivers for the adoption of nuclear heat and power plants. The cost of the hot water piping system from the nuclear plant to the city is a major factor in determining the feasibility of using nuclear heat. To achieve reasonable costs, the heat load should be at least 1500 MW(th), transport temperatures 125-200 0 C and distances preferably 50 km or less. Heat may be extracted from the turbines of conventional power reactors. Alternatively, some special-purpose smaller reactors are under development which are specially suited to production of heat with little or no power coproduct. Many countries are conducting studies of future expansions of district heating systems to use nuclear heat. Several countries are developing technology suitable for this application. Actual experience with the use of nuclear heat for district heating is currently being gained only in the USSR, however. While district heating appears to be a desirable technology at a time of increasing fossil-fuel costs, the use of nuclear heat will require siting of nuclear plants within transmission radius of cities. The institutional barries toward use of nuclear heating will have to be overcome before the energy conservation potential of this approach can be realized on a significant scale. (author)

Nuclear steam turbines for power production in combination with heating

International Nuclear Information System (INIS)

Frilund, B.; Knudsen, K.

1977-01-01

The general operating conditions for nuclear steam turbines in district heating system are briefly outlined. The turbine plant can consist of essentially the same types of machines as in conventional district heating systems. Some possible arrangements of back-pressure turbines, back-pressure turbines with condensing tails, or condensing turbines with heat extraction are considered for nuclear power and heat stations. Principles of control for hot water temperature and electrical output are described. Optimization of the plant, considering parallel variations during the year between heat load, cooling water temperature, and required outgoing temperature is discussed. (U.K.)

An inter-comparison of six latent and sensible heat flux products over the Southern Ocean

Directory of Open Access Journals (Sweden)

Lejiang Yu

2011-11-01

Full Text Available The latent heat fluxes (LHF and sensible heat fluxes (SHF over the Southern Ocean from six different data sets are inter-compared for the period 1988–2000. The six data sets include three satellite-based products, namely, the second version of the Goddard Satellite-Based Surface Turbulent Fluxes data set (GSSTF-2, the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3 and the Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO; two global reanalysis products, namely, the National Centers for Environmental Prediction–Department of Energy Reanalysis 2 data set (NCEP-2 and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis data set (ERA-40; and the Objectively Analyzed Air–Sea Fluxes for the Global Oceans data set (OAFlux. All these products reveal a similar pattern in the averaged flux fields. The zonal mean LHF fields all exhibit a continuous increase equatorward. With an exception of HOAPS-3, the zonal mean SHF fields display a minimum value near 50°S, increasing both pole- and equatorward. The differences in the standard deviation for LHF are larger among the six data products than the differences for SHF. Over the regions where the surface fluxes are significantly influenced by the Antarctic Oscillation and the Pacific–South American teleconnection, the values and distributions of both LHF and SHF are consistent among the six products. It was found that the spatial patterns of the standard deviations and trends of LHF and SHF can be explained primarily by sea–air specific humidity and temperature differences; wind speed plays a minor role.

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

Energy Technology Data Exchange (ETDEWEB)

Gautam, Bhoj; Warrell, Gregory; Shvydka, Diana; Ishmael Parsai, E., E-mail: e.parsai@utoledo.edu [University of Toledo Medical Center, 3000 Arlington Avenue, MS1151, Toledo, Ohio 43614 (United States); Subramanian, Manny [BEST Medical International, Inc., 7643 Fullerton Road, Springfield, Virginia 22153 (United States)

2014-02-15

Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulating thermal properties. Methods: The new seed's geometry is based on the standard BEST Model 2301{sup 125}I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni–Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50 °C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni–Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni–Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

International Nuclear Information System (INIS)

Gautam, Bhoj; Warrell, Gregory; Shvydka, Diana; Ishmael Parsai, E.; Subramanian, Manny

2014-01-01

Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulating thermal properties. Methods: The new seed's geometry is based on the standard BEST Model 2301 125 I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni–Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50 °C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni–Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni–Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT images

r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

Energy Technology Data Exchange (ETDEWEB)

Lippuner, Jonas; Roberts, Luke F., E-mail: jlippuner@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, MC 350-17, 1200 E California Boulevard, Pasadena CA 91125 (United States)

2015-12-20

r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

International Nuclear Information System (INIS)

Lippuner, Jonas; Roberts, Luke F.

2015-01-01

r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y e , initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y e ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y e lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y e , but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y e , s, and τ to estimate whether or not the ejecta is lanthanide-rich

Production of structured soy-based meat analogues using simple shear and heat in a Couette Cell

NARCIS (Netherlands)

Krintiras, G.A.; Gobel, T.W.; Goot, van der A.J.; Stefanidis, G.D.

2015-01-01

A Couette Cell device was employed to provide proof of concept for the production of structured meat analogues by application of simple shear flow and heat to a 31 wt% Soy Protein Isolate (SPI)–Wheat Gluten (WG) dispersion. Three relevant process parameters (temperature, time and rotation rate) were

Using flowering and heat-loss models for improving greenhouse energy-use efficiency in annual bedding plant production

Science.gov (United States)

In temperate climates, annual bedding plants are typically produced in heated greenhouses from late winter through early summer. Temperature, photoperiod, light intensity, and transplant date are commonly manipulated during commercial production so that plants are in flower for predetermined market ...

Influence of High Temperature and Duration of Heating on the Sunflower Seed Oil Properties for Food Use and Bio-diesel Production.

Science.gov (United States)

Giuffrè, Angelo Maria; Capocasale, Marco; Zappia, Clotilde; Poiana, Marco

2017-01-01

Two important problems for the food industry are oil oxidation and oil waste after frying. Sunflower seed oil is one of the vegetable oils most commonly used in the food industry. Two variables were applied to the low oleic sunflower seed oil in this work i.e. heating temperature (180-210-240°C) and time of heating (15-30-60-120 minutes), to study from the edible point of view the variations of its physico-chemical properties. After 120 minutes heating at 240°C the following was found: refractive index (1.476), free acidity (0.35%), K232 (2.87), K270 (3.71), antiradical activity (45.90% inhibition), total phenols (523 mg kg -1 ), peroxide value (17.00 meq kg -1 ), p-anisidine value (256.8) and Totox (271.7), all of which showed a constant deterioration. In relation to the use as a feedstock for bio-diesel production, after 120 minutes heating at 240℃ the following was found: acid value 0.70 mg KOH g -1 oil, iodine value 117.83 g I 2 100 g -1 oil, oil stability index 0.67 h, kinematic viscosity (at 40°C) 77.85 mm 2 s -1 , higher heating value 39.86 MJ kg -1 , density 933.34 kg/m 3 and cetane number 67.04. The parameters studied in this work were influenced, in different ways, by the applied variables. Heating temperature between 180 and 210°C and 120 min heating duration were found to be the most appropriate conditions for sunflower seed oil both from the deep frying point of view and from a subsequent use as feedstock for bio-diesel production. In light of the vegetable oils' International standards for an edible use and for a bio-diesel production, findings of this work can be used to set heating temperature and heating duration to preserve as long possible the physico-chemical properties of a low oleic sunflower seed oil for both its edible use as a fat during cooking and for its re-use after frying.

Occupational Heat Stress Profiles in Selected Workplaces in India.

Science.gov (United States)

Venugopal, Vidhya; Chinnadurai, Jeremiah S; Lucas, Rebekah A I; Kjellstrom, Tord

2015-12-29

Health and productivity impacts from occupational heat stress have significant ramifications for the large workforce of India. This study profiled occupational heat stress impacts on the health and productivity of workers in select organized and unorganized Indian work sectors. During hotter and cooler seasons, Wet Bulb Globe Temperatures (WBGT) were used to quantify the risk of heat stress, according to International workplace guidelines. Questionnaires assessed workers' perceived health and productivity impacts from heat stress. A total of 442 workers from 18 Indian workplaces participated (22% and 78% from the organized and unorganized sector, respectively). Overall 82% and 42% of workers were exposed to higher than recommended WBGT during hotter and cooler periods, respectively. Workers with heavy workloads reported more heat-related health issues (chi square = 23.67, p ≤ 0.001) and reduced productivity (chi square = 15.82, p ≤ 0.001), especially the outdoor workers. Heat-rashes, dehydration, heat-syncope and urinogenital symptoms were self-reported health issues. Cited reasons for productivity losses were: extended-work hours due to fatigue/exhaustion, sickness/hospitalization and wages lost. Reducing workplace heat stress will benefit industries and workers via improving worker health and productivity. Adaptation and mitigation measures to tackle heat stress are imperative to protect the present and future workforce as climate change progresses.

Occupational Heat Stress Profiles in Selected Workplaces in India

Science.gov (United States)

Venugopal, Vidhya; Chinnadurai, Jeremiah S.; Lucas, Rebekah A. I.; Kjellstrom, Tord

2015-01-01

Health and productivity impacts from occupational heat stress have significant ramifications for the large workforce of India. This study profiled occupational heat stress impacts on the health and productivity of workers in select organized and unorganized Indian work sectors. During hotter and cooler seasons, Wet Bulb Globe Temperatures (WBGT) were used to quantify the risk of heat stress, according to International workplace guidelines. Questionnaires assessed workers’ perceived health and productivity impacts from heat stress. A total of 442 workers from 18 Indian workplaces participated (22% and 78% from the organized and unorganized sector, respectively). Overall 82% and 42% of workers were exposed to higher than recommended WBGT during hotter and cooler periods, respectively. Workers with heavy workloads reported more heat-related health issues (chi square = 23.67, p ≤ 0.001) and reduced productivity (chi square = 15.82, p ≤ 0.001), especially the outdoor workers. Heat-rashes, dehydration, heat-syncope and urinogenital symptoms were self-reported health issues. Cited reasons for productivity losses were: extended-work hours due to fatigue/exhaustion, sickness/hospitalization and wages lost. Reducing workplace heat stress will benefit industries and workers via improving worker health and productivity. Adaptation and mitigation measures to tackle heat stress are imperative to protect the present and future workforce as climate change progresses. PMID:26729144

Numerical Modelling of Indution Heating - Fundamentals

DEFF Research Database (Denmark)

Zhang, Wenqi

Induction heating is extensively used for brazing and heat treatment of materials to produce consumer and industrial products; structural assemblies; electrical and electronic products; mining, machine, and hand tools; ordnance equipment; and aerospace assemblies. It is often applied when rapid a...

The effect of heat pretreatment temperature on fermentative hydrogen production using mixed cultures

Energy Technology Data Exchange (ETDEWEB)

Baghchehsaraee, Bita; Nakhla, George; Karamanev, Dimitre; Margaritis, Argyrios [Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Reid, Gregor [Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario (Canada); Canadian Research and Development Center for Probiotics, Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario N6A 4V2 (Canada)

2008-08-15

The effect of heat treatment at different temperatures on two types of inocula, activated sludge and anaerobically digested sludge, was investigated in batch cultures. Heat treatments were conducted at 65, 80 and 95 C for 30 min. The untreated inocula produced less amount of hydrogen than the pretreated inocula, with lactic acid as the main metabolite. The maximum yields of 2.3 and 1.6 mol H{sub 2}/mol glucose were achieved for the 65 C pretreated anaerobically digested and activated sludges, respectively. Approximately a 15% decrease in yield was observed with increasing pretreatment temperature from 65 to 95 C concomitant with an increase in butyrate/acetate ratio from 1.5 to 2.4 for anaerobically digested sludge. The increase of pretreatment temperature of activated sludge to 95 C suppressed the hydrogen production by lactic acid fermentation. DNA analysis of the microbial community showed that the elevated pretreatment temperatures reduced the species diversity. (author)

Heat Driven Cooling in District Energy Systems; Vaermedriven Kyla

Energy Technology Data Exchange (ETDEWEB)

Rydstrand, Magnus; Martin, Viktoria; Westermark, Mats [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

2004-07-01

This report is reviewing different heat driven technologies for the production of cooling. It is shown that the supply of cooling gives the highest fuel utilization if heat from CHP production is used for the production of cooling instead of maximizing the electricity output in a condensing plant. High fuel utilization is reached since the direct production of cooling from heat is a thermodynamic shortcut as compared to the production of electricity as an intermediate product before cooling is produced. At direct production of cooling from heat it is possible to obtain 70 percent of the obtainable cooling of an ideal process. If electricity is produced from heat, 70 percent electricity could be obtained as compared to an ideal process. If this electricity would be used for the production of cooling 70 percent of the obtainable cooling in an ideal process would the result. The total production of cooling from heat with electricity as an intermediate product would therefore give 50 percent cooling as compared to an ideal process. Hence, heat driven cooling will give more cooling for a given fuel input. In the review of the different heat driven cooling options it was found that there are many alternatives suitable for different applications. Absorption cooling is suitable for water distributed cooling if the latent cooling load is low. Desiccant cooling is believed to have a large market in climates (applications) with high latent cooling loads. In the energy efficiency evaluation it is found that the highest fuel utilization is given for a central production of electricity using either district heating or district cooling as the energy carrier to supply cooling. In fact the potential of district heating as the energy carrier is thought to be the largest in large cities with humid climates. Further it is found that the chiller heat sink can contribute significantly to the cost in many applications, especially if water and/or electricity consumption are issues with

Sensitivity of district heating system operation to heat demand reductions and electricity price variations: A Swedish example

International Nuclear Information System (INIS)

Åberg, M.; Widén, J.; Henning, D.

2012-01-01

In the future, district heating companies in Sweden must adapt to energy efficiency measures in buildings and variable fuel and electricity prices. Swedish district heating demands are expected to decrease by 1–2% per year and electricity price variations seem to be more unpredictable in the future. A cost-optimisation model of a Swedish local district heating system is constructed using the optimisation modelling tool MODEST. A scenario for heat demand changes due to increased energy efficiency in buildings, combined with the addition of new buildings, is studied along with a sensitivity analysis for electricity price variations. Despite fears that heat demand reductions will decrease co-generation of clean electricity and cause increased global emissions, the results show that anticipated heat demand changes do not increase the studied system's primary energy use or global CO 2 emissions. The results further indicate that the heat production plants and the fuels used within the system have crucial importance for the environmental impact of district heat use. Results also show that low seasonal variations in electricity price levels with relatively low winter prices promote the use of electric heat pumps. High winter prices on the other hand promote co-generation of heat and electricity in CHP plants. -- Highlights: ► A MODEST optimisation model of the Uppsala district heating system is built. ► The impact of heat demand change on heat and electricity production is examined. ► An electricity price level sensitivity analysis for district heating is performed. ► Heat demand changes do not increase the primary energy use or global CO 2 emissions. ► Low winter prices promote use of electric heat pumps for district heating production.

Performance Analysis of a Hybrid District Heating System

DEFF Research Database (Denmark)

Mikulandric, Robert; Krajačić, Goran; Duic, Neven

2015-01-01

Hybridisation of district heating systems can contribute to more efficient heat generation through cogeneration power plants or through the share increase of renewable energy sources in total energy consumption while reducing negative aspects of particular energy source utilisation. In this work......, the performance of a hybrid district energy system for a small town in Croatia has been analysed. Mathematical model for process analysis and optimisation algorithm for optimal system configuration has been developed and described. The main goal of the system optimisation is to reduce heat production costs....... Several energy sources for heat production have been considered in 8 different simulation cases. Simulation results show that the heat production costs could be reduced with introduction of different energy systems into an existing district heating system. Renewable energy based district heating systems...

From Product to System Approaches in European Sustainable Product Policies: Analysis of the Package Concept of Heating Systems in Buildings

Directory of Open Access Journals (Sweden)

Maria Calero-Pastor

2017-09-01

Full Text Available Different policies with the goal of reducing energy consumption and other environmental impacts in the building sector coexist in Europe. Sustainable product polices, such as the Ecodesign and Energy Labelling Directives, have recently broadened the scope of their target product groups from a strict product approach to extended product and system approaches. Indeed, there is a potential for greater savings when the focus is at a system level rather than on regulating individual products. Product policies for space and water heating systems have recently introduced and implemented the package label, which is a modular approach, standing between the extended product and the system approaches. This paper presents a systematic analysis of the different system approaches of various policies from an engineering perspective. It analyses in detail the package concept and its features through a practical application using a real case study. It focuses on how the package concept can support decisions made in the building design phase and, in particular, how can support the choice of appropriate components based on estimating system performances. This brings building engineers and regulators closer regarding the use of more consistent data on energy performance. Finally, this paper highlights the need to improve the alignment of the building-related product policies with the Energy Performance of Buildings Directive.

Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

Science.gov (United States)

Peterman, D. D.; Fontaine, R. W.; Quade, R. N.; Halvers, L. J.; Jahromi, A. M.

1975-01-01

The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program.

Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

International Nuclear Information System (INIS)

Peterman, D.D.; Fontaine, R.W.; Quade, R.N.; Halvers, L.J.; Jahromi, A.M.

1975-01-01

The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program

Elimination of Acid Cleaning of High Temperature Salt Water Heat Exchangers: Redesigned Pre-Production Full-Scale Heat Pipe Bleed Air Cooler for Shipboard Evaluation

Science.gov (United States)

2011-11-01

Acronyms ASW Anti Submarine Warfare AUX Auxillary Room BAC Bleed Air Cooler BAS Bleed Air System BTU British Thermal Unit BOSS...improvements which should be considered when making a production decision following successful shipboard tests. 5. Since this technology was proposed...However, to maintain schedule, a decision was made prior to this structural analysis being completed on how long to make the heat pipes. With using the

High temperature absorption compression heat pump for industrial waste heat

DEFF Research Database (Denmark)

Reinholdt, Lars; Horntvedt, B.; Nordtvedt, S. R.

2016-01-01

Heat pumps are currently receiving extensive interest because they may be able to support the integration of large shares of fluctuating electricity production based on renewable sources, and they have the potential for the utilization of low temperature waste heat from industry. In most industries......, the needed temperature levels often range from 100°C and up, but until now, it has been quite difficult to find heat pump technologies that reach this level, and thereby opening up the large-scale heat recovery in the industry. Absorption compression heat pumps can reach temperatures above 100°C......, and they have proved themselves a very efficient and reliable technology for applications that have large temperature changes on the heat sink and/or heat source. The concept of Carnot and Lorenz efficiency and its use in the analysis of system integration is shown. A 1.25 MW system having a Carnot efficiency...

Heating unit of Berovo by co-generation (Macedonia)

International Nuclear Information System (INIS)

Armenski, Slave; Dimitrov, Konstantin; Tashevski, Done

1999-01-01

A plant for combined heat and electric power production, for central heating of the town Berovo (Macedonia) is proposed. The common reason to use a co-generation unit is the energy efficiency and a significant reduction of environmental pollution. The heat consumption of town Berovo is analyzed and determined. Based on the energy consumption of a whole power plant, e. i. the plant for combined and simultaneous production of power is proposed. The quantity of annually heat and electrical production and annually coal consumption are estimated. (Author)

Allocation of fossil and nuclear fuels. Heat production from chemically and physically bound energy

International Nuclear Information System (INIS)

Wagner, U.

2008-01-01

The first part of the book presents the broad field of allocation, transformation, transport and distribution of the most important energy carriers in the modern power industry. The following chapters cover solid fossil fuel, liquid fuel, gaseous fuel and nuclear fuel. The final chapters concern the heat production from chemically and physically bound energy, including elementary analysis, combustion calculations, energy balance considerations in fossil fuel fired systems, and fundamentals of nuclear physics

Heat Stress and feeding strategies in meat-type chickens

NARCIS (Netherlands)

Syafwan, W.; Kwakkel, R.P.; Verstegen, M.W.A.

2011-01-01

Heat stress can induce hyperthermia in poultry. A reduction in heat load can be achieved by increasing the possibilities for dissipation, decreasing the level of heat production or by changing the thermal production pattern within a day. Strategies to reduce the negative effects of heat stress can

The production of hydrotalcite from magnesite ore as non-toxic heat stabiliser for polyvinyl chloride

Directory of Open Access Journals (Sweden)

J. van der Laan

2005-09-01

Full Text Available In recent years polyvinyl chloride (PVC processors had to submit to worldwide pressure to convert to environmentally friendly stabilisers such as hydrotalcite (HT, since most of the heat stabilisers currently in use contain heavy metals such as lead, cadmium or barium – these being highly toxic. The presently used HT production process is, however, very expensive as it involves the recovering of magnesium from seawater magnesia. The purpose of this study was to prove that it is indeed possible to produce cost effective and non-toxic HT from an alternative source. During this study the costing and heat stabilising ability of the hydrotalcite produced from magnesite was compared to that of commercially available heat stabilisers. The effect of the pre-mixing process, as well as the influence of particle size distribution was also investigated. A cost comparative and stabilising efficiency study indicated the cost effectiveness of HT produced from magnesite ore, in comparison with other commercially available stabilisers. The use of HT as produced from magnesite ore would indeed assist in the worldwide changeover to environmentally friendly stabilisers.

Effect of heat treatment and dough formulation on the formation of Maillard reaction products in fine bakery products - benefits and weak points

OpenAIRE

Ciesarová, Z.; Kukurová, K.; Bednáriková, A.; Morales, F. J.

2009-01-01

Possibly harmful compounds (acrylamide, 5-(hydroxymethyl)-2-furfural - HMF), markers of the Maillard reaction extent (furosine, fluorescence, browning, colour), as well as beneficial radical-scavenging capacity were determined in fried fine bakery products, rosquillas, at different heat treatment and dough formulation. In different simplified recipes, saccharose was substituted by glucose and fructose, and a raising agent was added while different temperature and time regimes were applied. Du...

HTGR-GT closed-cycle gas turbine: a plant concept with inherent cogeneration (power plus heat production) capability

International Nuclear Information System (INIS)

McDonald, C.F.

1980-04-01

The high-grade sensible heat rejection characteristic of the high-temperature gas-cooled reactor-gas turbine (HTGR-GT) plant is ideally suited to cogeneration. Cogeneration in this nuclear closed-cycle plant could include (1) bottoming Rankine cycle, (2) hot water or process steam production, (3) desalination, and (4) urban and industrial district heating. This paper discusses the HTGR-GT plant thermodynamic cycles, design features, and potential applications for the cogeneration operation modes. This paper concludes that the HTGR-GT plant, which can potentially approach a 50% overall efficiency in a combined cycle mode, can significantly aid national energy goals, particularly resource conservation

Isotope heating block

International Nuclear Information System (INIS)

Wenk, E.

1976-01-01

A suggestion is made not to lead the separated nuclear 'waste' from spent nuclear fuel elements directly to end storage, but to make use of the heat produced from the remaining radiation, e.g. for seawater desalination. According to the invention, the activated fission products are to be processed, e.g. by calcination or vitrification, so that one can handle them. They should then be arranged in layers alternately with plate-shaped heat conducting pipes to form a homogeneous block; the heat absorbed by the thermal plates should be further passed on to evaporators or heat exchangers. (UWI) [de

Reactor waste heat utilization and district heating reactors. Nuclear district heating in Sweden - Regional reject heat utilization schemes and small heat-only reactors

International Nuclear Information System (INIS)

Hannerz, K.; Larsson, Y.; Margen, P.

1977-01-01

A brief review is given of the current status of district heating in Sweden. In future, district heating schemes will become increasingly interesting as a means of utilizing heat from nuclear reactors. Present recommendations in Sweden are that large reactors should not be located closer than about 20 km from large population centres. Reject heat from such reactors is cheap at source. To minimize the cost of long distance hot water transmission large heat rates must be transmitted. Only areas with large populations can meet this requirement. The three areas of main interest are Malmoe/Lund/Helsingborg housing close to 0.5 million; Greater Stockholm housing 1 to 1.5 million and Greater Gothenburg housing about 0.5 million people. There is an active proposal that the Malmoe/Lund/Helsingborg region would be served by a third nuclear unit at Barsebaeck, located about 20 km from Malmoe/Lund and supplying 950 MW of base load heat. Preliminary proposals for Stockholm involve a 2000 MW heat supply; proposals for Gothenburg are more tentative. The paper describes progress on these proposals and their technology. It also outlines technology under development to increase the economic range of large scale heat transport and to make distribution economic even for low heat-density family housing estates. Regions apart from the few major urban areas mentioned above require the adoption of a different approach. To this end the development of a small, simple low-temperature reactor for heat-only production suitable for urban location has been started in Sweden in close contact with Finland. Some results of the work in progress are presented, with emphasis on the safety requirements. An outline is given in the paper as to how problems of regional heat planning and institutional and legislative issues are being approached

77 FR 33486 - Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products...

Science.gov (United States)

2012-06-06

...Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products Containing Same, DN 2899; the Commission is soliciting comments on any public interest issues raised by the complaint or complainant's filing under section 210.8(b) of the Commission's Rules of Practice and Procedure (19 CFR 210.8(b)).

Geothermal source heat pumps under energy services companies finance scheme to increase energy efficiency and production in stockbreeding facilities

International Nuclear Information System (INIS)

Borge-Diez, David; Colmenar-Santos, Antonio; Pérez-Molina, Clara; López-Rey, África

2015-01-01

In Europe energy services are underutilized in terms of their potential to improve energy efficiency and reduce external energy dependence. Agricultural and stockbreeding sectors have high potential to improve their energy efficiency. This paper presents an energy model for geothermal source heat pumps in stockbreeding facilities and an analysis of an energy services business case. The proposed solution combines both energy cost reduction and productivity increases and improves energy services company financing scheme. CO 2 emissions drop by 89%, reducing carbon footprint and improving added value for the product. For the two different evaluated scenarios, one including winter heating and one including heating and cooling, high IRR (internal return rate) values are obtained. A sensitivity analysis reveals that the IRR ranges from 10.25% to 22.02%, making the investment attractive. To make the research highly extensible, a sensitivity analysis for different locations and climatic conditions is presented, showing a direct relationship between financial parameters and climatic conditions. A Monte Carlo simulation is performed showing that initial fuel cost and initial investment are the most decisive in the financial results. This work proves that energy services based on geothermal energy can be profitable in these sectors and can increase sustainability, reduce CO 2 emissions and improve carbon footprint. - Highlights: • Geothermal heat pumps are studied to promote industrial energy services. • Geothermal energy in farming facilities improves global competitiveness. • Research shows profitability of low enthalpy geothermal energy services. • Climatic conditions sensitivity analysis reveals IRR ranges from 10.25% to 22.02%. • Added market value for the product as carbon footprint reduction, are achieved

Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

DEFF Research Database (Denmark)

Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

2014-01-01

pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic......District heating makes it possible to provide heat for many consumers in an efficient manner. In particular, district heating based on combined heat and power production is highly efficient. One disadvantage of district heating is that there is a significant heat loss from the pipes...... to the surrounding ground. In larger networks involving both transmission and distribution systems, the heat loss is most significant from the distribution network. An estimate is that about 80-90 % of the heat loss occurs in the distribution system. In addition, the heat loss is naturally highest from the forward...

Radioactivity and radiogenic heat production in the oil field of the Reconcavo Basin; Radioatividade e geracao de calor radiogenico em pocos petroliferos na Bacia do Reconcavo

Energy Technology Data Exchange (ETDEWEB)

Alves Junior, Paulo B.; Argollo, Roberto M. de [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Centro de Pesquisa em Geofisica e Geologia

2004-07-01

The production of radiogenic heat in the terrestrial crust is due mainly to U, Th and K presents in the rocks. In this work, we use the gamma-ray spectrometry technique to determine the contents of these elements in drill cuttings and obtaining profiles of heat production rates in oils wells of the Reconcavo basin. In the total, we measure 640 samples of drill cuttings from wells FFL-1 and MGP-34 ceded by PETROBRAS. The thorium contents vary from 1.6 to 25.5 ppm, the uranium contents varied from 0.5 to 5.82 ppm, the potassium samples varied from 0.05 to 2.25 % and the production rates of radiogenic heat varied among 0.50 to 10.85 10{sup -4} {mu}W kg{sup -1}. With the profiles heat production rates obtained, a correlation was verified among these rates and the lithologies at wells FFL-1 and MGP-34. These values will be used in the correlation between these samples at wells and the sample collected at blooming. (author)

Potential utilization of biomass in production of electricity, heat and transportation fuels including energy combines - Regional analyses and examples; Potentiell avsaettning av biomassa foer produktion av el, vaerme och drivmedel inklusive energikombinat - Regionala analyser och raekneexempel

Energy Technology Data Exchange (ETDEWEB)

Ericsson, Karin; Boerjesson, Paal

2008-01-15

The objective of this study is to analyse how the use of biomass may increase in the next 10-20 years in production of heat, electricity and transportation fuels in Sweden. In these analyses, the biomass is assumed to be used in a resource and cost efficient way. This means for example that the demand for heat determines the potential use of biomass in co-generation of heat and electricity and in energy combines, and that the markets for by-products determine the use of biomass in production of certain transportation fuels. The economic conditions are not analysed in this study. In the heat and electricity production sector, we make regional analyses of the potential use of biomass in production of small-scale heat, district heat, process heat in the forest industry and electricity produced in co-generation with heat in the district heating systems and forest industry. These analyses show that the use of biomass in heat and electricity production could increase from 87 TWh (the use in 2004/2005, excluding small-scale heat production with firewood) to between 113 TWh and 134 TWh, depending on the future expansion of the district heating systems. Geographically, the Stockholm province accounts for a large part of the potential increase owing to the great opportunities for increasing the use of biomass in production of district heat and CHP in this region. In the sector of transportation fuels we applied a partly different approach since we consider the market for biomass-based transportation fuels to be 'unconstrained' within the next 10-20 years. Factors that constrain the production of these fuels are instead the availability of biomass feedstock and the local conditions required for achieving effective production systems. Among the first generation biofuels this report focuses on RME and ethanol from cereals. We estimate that the domestic production of RME and ethanol could amount to up to 1.4 TWh/y and 0.7-3.8 TWh/y, respectively, where the higher figure

Vilnius district heating pilot project. Final report. Annex 1-14

International Nuclear Information System (INIS)

1995-03-01

The present energy scenario model is based on the SYSTEM ROERNET energy planning module and includes the energy flows from the energy source to the consumer for space heating and domestic hot water. The energy sources are: District heating of City based on CHP or/and heat-only production. District heating of Naujoji Vilnia based on heat-only production. Local boilers using natural gas or heavy fuel oil. Stoves using kerosene, coke or wood. (Electricity panel might be included, but this has not been the case in the actual analyses). The calculations of the energy model results in estimation of: Annual heat production, especially simulation of the plant production for district heating system with the possibility of integrated pooled operation by giving an order of priority to each plant based on the efficiency of the plant. Annual fuel consumption and the fuel costs for the society. Annual electricity production and its value to the society. Annual operation and maintenance costs including costs connected with consumption of electricity for district heating purposes. The total annual investments due to the set of options applied in the scenario in question. Savings in plant investments if less production capacity is necessary in scenarios where the heat demand is decreasing. The flue gas emissions from the heat and CHP production in the Vilnius area are estimated by CO 2 , SO 3 , NO x and particulates. These emissions are not reduced by the possible savings of electricity production of a reference power-only plant outside Vilnius. (EG)

Detection of horse meat contamination in raw and heat-processed meat products.

Science.gov (United States)

Hsieh, Yun-Hwa P; Ofori, Jack A