Cooking utensil with improved heat retention

Science.gov (United States)

Potter, T.F.; Benson, D.K.; Burch, S.D.

1997-07-01

A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber there between. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food. 26 figs.

Cooking utensil with improved heat retention

Science.gov (United States)

Potter, Thomas F.; Benson, David K.; Burch, Steven D.

1997-01-01

A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber therebetween. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food.

Effects of heat stress on bovine preimplantation embryos produced in vitro.

Science.gov (United States)

Sakatani, Miki

2017-08-19

Summer heat stress decreases the pregnancy rate in cattle and has been thought to be associated with the early embryonic death caused by the elevation of maternal body temperature. In vitro cultures have been widely used for the evaluation of effects of heat stress on oocytes, fertilization, preimplantation, and embryonic development. Susceptibility to heat stress is present in developmental stages from oocytes to cleavage-stage (before embryonic gene activation, EGA) embryos, leading to a consequent decrease in developmental competence. On the other hand, advanced-stage embryos such as morula or blastocysts have acquired thermotolerance. The mechanism for the developmental stage-dependent change in thermotolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. The supplementation of antioxidants to the culture media has been known to neutralize the detrimental effects of heat stress. Besides, EGA could be involved in acquisition of thermotolerance in later stages of embryos. Morulae or blastocysts can repair heat-induced unfolded proteins or prevent DNA damage occurring in processes such as apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the pregnancy rate under heat stress. However, frozen-thawed ET could not improve the pregnancy rate as expected. Frozen-thawed blastocysts were more sensitive to heat stress and showed less proliferation upon heat exposure, compared to fresh blastocysts. Therefore, further research is required to improve the reduction in pregnancy rates due to summer heat stress.

Effect of γ-Aminobutyric Acid-producing Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress

Directory of Open Access Journals (Sweden)

Y. Z. Zhu

2015-07-01

Full Text Available Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164 at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i 0 mg/kg, ii 25 mg/kg, iii 50 mg/kg, and iv 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05 by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05 than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009 and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to

[Environmental and health impacts of wood combustion to produce heat and power].

Science.gov (United States)

Valerio, Federico

2012-01-01

Toxic chemicals such as benzene, polycyclic aromatic hydrocarbons, dioxins, and ultra fine particles were found in the smoke produced by wood combustion. Emission factors confirm that, to produce the same energy amount, many more pollutants are emitted by wood than by natural gas. Biomass burning produces a relevant deterioration of air quality inside and outside houses, notably due to emissions of fine and ultra fine dust (PM10, PM2.5) according to reviewed studies. Important improvements in emission quality are obtained with the use of more efficient household heating systems, both in developed and in developing countries. Numerous studies have assessed the possible health effects produced by wood smoke, providing sufficient evidence that the indoor exposure to wood smoke, even in developed countries, can have adverse effects on human health. In 2010 IARC classified wood smoke as a possible human carcinogen. In Europe, electricity generation from biomass combustion is increasing (12% each year) thanks to incentives provided to reduce greenhouse gas emissions and use of fossil fuels.Today adequate studies to assess the environmental and health effects of emissions from power plants fuelled by solid biomasses are still needed.

Heat treatment of Ti6Al4V produced by Selective Laser Melting: Microstructure and mechanical properties

International Nuclear Information System (INIS)

Vrancken, Bey; Thijs, Lore; Kruth, Jean-Pierre; Van Humbeeck, Jan

2012-01-01

Highlights: ► Responses of SLM-produced and wrought Ti6Al4V to heat treatment are compared. ► Temperature is found to be the controlling parameter for treatments in the α + β range. ► Ductility could be improved by a factor of 85%, from 7.27% to 13.59%. ► An optimal heat treatment for SLM produced Ti6Al4V is proposed. - Abstract: The present work shows that optimization of mechanical properties via heat treatment of parts produced by Selective Laser Melting (SLM) is profoundly different compared to conventionally processed Ti6Al4V. In order to obtain optimal mechanical properties, specific treatments are necessary due to the specific microstructure resulting from the SLM process. SLM is an additive manufacturing technique through which components are built by selectively melting powder layers with a focused laser beam. The process is characterized by short laser-powder interaction times and localized high heat input, which leads to steep thermal gradients, rapid solidification and fast cooling. In this research, the effect of several heat treatments on the microstructure and mechanical properties of Ti6Al4V processed by SLM is studied. A comparison is made with the effect of these treatments on hot forged and subsequently mill annealed Ti6Al4V with an original equiaxed microstructure. For SLM produced parts, the original martensite α′ phase is converted to a lamellar mixture of α and β for heat treating temperatures below the β-transus (995 °C), but features of the original microstructure are maintained. Treated above the β-transus, extensive grain growth occurs and large β grains are formed which transform to lamellar α + β upon cooling. Post treating at 850 °C for 2 h, followed by furnace cooling increased the ductility of SLM parts to 12.84 ± 1.36%, compared to 7.36 ± 1.32% for as-built parts.

Heat treatment for improvement in lower temperature mechanical properties of 0.40 pct C-Cr-Mo ultrahigh strength steel

Science.gov (United States)

Tomita, Yoshiyuki; Okabayashi, Kunio

1983-11-01

In the previous paper, it was reported that isothermal heat treatment of a commercial Japanese 0.40 pct C-Ni-Cr-Mo ultrahigh strength steel (AISI 4340 type) at 593 K for a short time followed by water quenching, in which a mixed structure of 25 vol pct lower bainite and 75 vol pct martensite is produced, results in the improvement of low temperature mechanical properties (287 to 123 K). The purpose of this paper is to study whether above new heat treatment will still be effective in commercial practice for improving low temperature mechanical properties of the ultrahigh strength steel when applied to a commercial Japanese 0.40 pct C-Cr-Mo ultrahigh strength steel which is economical because it lacks the expensive nickel component (AISI 4140 type). At and above 203 K this new heat treatment, as compared with the conventional 1133 K direct water quenching treatment, significantly improved the strength, tensile ductility, and notch toughness of the 0.40 pct C-Cr-Mo ultrahigh strength steel. At and above 203 K the new heat treatment also produced superior fracture ductility and notch toughness results at similar strength levels as compared to those obtained by using γ α' repetitive heat treatment for the same steel. However, the new heat treatment remarkably decreased fracture ductility and notch toughness of the 0.40 pct C-Cr-Mo ultrahigh strength steel below 203 K, and thus no significant improvement in the mechanical properties was noticeable as compared with the properties produced by the conventional 1133 K direct water quenching treatment and the γ α' repetitive heat treatment. This contrasts with the fact that the new heat treatment, as compared with the conventional 1133 K direct water quenching treatment and the γ α' repetitive heat treatment, dramatically improved the notch toughness of the 0.40 pct C-Ni-Cr-Mo ultrahigh strength steel, providing a better combination of strength and ductility throughout the 287 to 123 K temperature range. The difference

Effect of γ-Aminobutyric Acid-producing Lactobacillus Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress.

Science.gov (United States)

Zhu, Y Z; Cheng, J L; Ren, M; Yin, L; Piao, X S

2015-07-01

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (pGABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (plevel was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

Air source absorption heat pump in district heating: Applicability analysis and improvement options

International Nuclear Information System (INIS)

Wu, Wei; Shi, Wenxing; Li, Xianting; Wang, Baolong

2015-01-01

Highlights: • Applicability of air source absorption heat pump (ASAHP) district heating is studied. • Return temperature and energy saving rate (ESR) in various conditions are optimized. • ASAHP is more suitable for shorter distance or lower temperature district heating. • Two options can reduce the primary return temperature and improve the applicability. • The maximum ESR is improved from 13.6% to 20.4–25.6% by compression-assisted ASAHP. - Abstract: The low-temperature district heating system based on the air source absorption heat pump (ASAHP) was assessed to have great energy saving potential. However, this system may require smaller temperature drop leading to higher pump consumption for long-distance distribution. Therefore, the applicability of ASAHP-based district heating system is analyzed for different primary return temperatures, pipeline distances, pipeline resistances, supplied water temperatures, application regions, and working fluids. The energy saving rate (ESR) under different conditions are calculated, considering both the ASAHP efficiency and the distribution consumption. Results show that ASAHP system is more suitable for short-distance district heating, while for longer-distance heating, lower supplied hot water temperature is preferred. In addition, the advantages of NH 3 /H 2 O are inferior to those of NH 3 /LiNO 3 , and the advantages for warmer regions and lower pipeline resistance are more obvious. The primary return temperatures are optimized to obtain maximum ESRs, after which the suitable distances under different acceptable ESRs are summarized. To improve the applicability of ASAHP, the integration of cascaded heat exchanger (CHX) and compression-assisted ASAHP (CASAHP) are proposed, which can reduce the primary return temperature. The integration of CHX can effectively improve the applicability of ASAHP under higher supplied water temperatures. As for the utilization of CASAHP, higher compression ratio (CR) is better in

Improving the engineering strength of heat strengthened glass

NARCIS (Netherlands)

Veer, F.A.; Rodichev, YM

2016-01-01

Although glass is increasingly used as a structural material, glass is not produced to strength standards, like steel and concrete. Of the three types of glass: annealed, heat strengthened and fully tempered, only heat strengthened glass has the properties to function as a safe structural material.

Cost estimation of hydrogen and DME produced by nuclear heat utilization system. Joint research

International Nuclear Information System (INIS)

Shiina, Yasuaki; Nishihara, Tetsuo

2003-09-01

Research of hydrogen energy has been performed in order to spread use of the hydrogen energy in 2020 or 2030. It will take, however, many years for the hydrogen energy to be used very easily like gasoline, diesel oil and city gas in all of countries. During the periods, low CO 2 release liquid fuels would be used together with hydrogen. Recently, di-methyl-either (DME) has been noticed as one of the substitute liquid fuels of petroleum. Such liquid fuels can be produced from the mixed gas such as hydrogen and carbon oxide which are produced by steam reforming hydrogen generation system by the use of nuclear heat. Therefore, the system would be one of the candidates of future system of nuclear heat utilization. In the present study, we focused on the production of hydrogen and DME. Economic evaluation was estimated for hydrogen and DME production in commercial and nuclear heat utilization plant. At first, heat and mass balance of each process in commercial plant of hydrogen production was estimated and commercial prices of each process were derived. Then, price was estimated when nuclear heat was used instead of required heat of commercial plant. Results showed that the production prices produced by nuclear heat were cheaper by 10% for hydrogen and 3% for DME. With the consideration of reduction effect of CO 2 release, utilization of nuclear heat would be more effective. (author)

Melatonin treatment at dry-off improves reproductive performance postpartum in high-producing dairy cows under heat stress conditions.

Science.gov (United States)

Garcia-Ispierto, I; Abdelfatah, A; López-Gatius, F

2013-08-01

The aim of this study was to determine the effect of melatonin treatment during the early dry-off period on subsequent reproductive performance and milk production in high-producing dairy cows under heat stress conditions. In experiment I, addressing the pharmacokinetics of melatonin treatment in lactating dairy cows, doses of untreated, 3, 6, 9 or 12 implants/animal (18-mg melatonin each implant) were given as subcutaneous implants on gestation day 120-20 multiparous lactating dairy cows (four cows/dose group). Experiment II was performed during the warm season on 25 heifers and 114 high milk-producing Holstein-Friesian cows. Animals were randomly assigned to a control (C) or melatonin group (M). Animals in the M group received nine implants (heifers) or 12 (cows) of melatonin on day 220 of gestation. In experiment I, cows in the 12 implants group showed a higher maximum melatonin concentration (Cmax ) and area under the concentration curve from treatment day 0 to day 49 (AUC0-49d ) than those in the remaining groups, among which there were no significant differences in this variable. In experiment II, the likelihood of repeat breeding syndrome (pregnancy loss (first trimester) were 0.36 and 0.19 times lower in treated than control animals, respectively. Plasma prolactin levels decreased significantly (p = 0.01) after melatonin treatment and recovered during the postpartum compared to control cows. No significant effects on milk production were observed in the subsequent lactation. Significant differences in days open between groups (means 123 ± 71.9 and 103 ± 43, respectively, for C and M; p = 0.02) were registered. In conclusion, melatonin treatment in the early dry-off period improves the reproductive performance of dairy cattle, reducing the number of days open, repeat breeding syndrome and pregnancy loss. © 2012 Blackwell Verlag GmbH.

Influence of heat treatments on the microstructure and tensile behaviour of selective laser melting-produced TI-6AL-4V parts

Directory of Open Access Journals (Sweden)

Ter Haar, Gerrit Matthys

2016-11-01

Full Text Available In industry, post-process heat treatments of Ti-6Al-4V are performed with the aim of improving its tensile behaviour. While heat treatments of wrought Ti6Al4V have been standardised (e.g., Aerospace Material Specification H-81200, heat treatments of selective laser melting (SLM-produced Ti-6Al-4V lacks research and understanding. Significant concern exists about SLM Ti6-Al-4V’s achievable ductility attributed to its martensitic (α’ phase. In this research, heat treatments at a range of temperatures are applied to SLM-produced Ti-6Al-4V tensile samples. Microstructural analysis (both optically and through electron backscatter diffraction was used to identify links between heat treatments and microstructure. Subsequently, uniaxial tensile tests were performed to determine the respective tensile properties of all samples. Correlations in the data show a significant loss in strength with respect to an increase in annealing temperature due to grain growth, while no noticeable trend was observed for fracture strain with regard to annealing temperatures.

Heat exchanger for transfering heat produced in a high temperature reactor to an intermediate circuit gas

International Nuclear Information System (INIS)

Barchewitz, E.; Baumgaertner, H.

1985-01-01

The invention is concerned with improving the arrangement of a heat exchanger designed to transfer heat from the coolant gas circuit of a high temperature reactor to a gas which is to be used for a process heat plant. In the plant the material stresses are to be kept low at high differential pressures and temperatures. According to the invention the tube bundles designed as boxes are fixed within the heat exchanger closure by means of supply pipes having got loops. For conducting the hot gas the heat exchanger has got a central pipe leading out of the reactor vessel through the pod closure and having got only one point of fixation, lying in this closure. Additional advantageous designs are mentioned. (orig./PW)

Heat production in an Archean crustal profile and implications for heat flow and mobilization of heat-producing elements

Energy Technology Data Exchange (ETDEWEB)

Ashwal, L.D.; Morgan, P.; Kelley, S.A.; Percival, J.A.

1987-10-01

We have measured concentrations of heat producing elements (Th, U, and K) in 58 samples representative of the main lithologies in a 100 km transect of the Superior Province of the Canadian Shield, from the Michipicoten (Wawa) greenstone belt, near Wawa, Ontario, through a domal gneiss terrane of amphibolite grade, to the granulite belt of the Kapuskasing Structural Zone, near Foleyet. (orig./SHOE).

Improving Process Heating System Performance v3

Energy Technology Data Exchange (ETDEWEB)

None

2016-04-11

Improving Process Heating System Performance: A Sourcebook for Industry is a development of the U.S. Department of Energy (DOE) Advanced Manufacturing Office (AMO) and the Industrial Heating Equipment Association (IHEA). The AMO and IHEA undertook this project as part of an series of sourcebook publications developed by AMO on energy-consuming industrial systems, and opportunities to improve performance. Other topics in this series include compressed air systems, pumping systems, fan systems, steam systems, and motors and drives

Improving district heating in Kiev

International Nuclear Information System (INIS)

Salminen, P.

2000-01-01

The district heating modernisation project currently under way in Kiev, the capital of the Ukraine, is the largest project of its type financed by the World Bank. The budget for the five-year project is some USD 250 million of which USD 200 million is financed by the World Bank loan. The target of the project is to improve the city's district heating system, which is owned and operated by Kyivenergo. Consultancy services for the Project Implementation Unit are being provided by Electrowatt-Ekono and financed by the Finnish government

Investigation on thermal environment improvement by waste heat recovery in the underground station in Qingdao metro

Science.gov (United States)

Liu, Jianwei; Liu, Jiaquan; Wang, Fengyin; Wang, Cuiping

2018-03-01

The thermal environment parameters, like the temperature and air velocity, are measured to investigate the heat comfort status of metro staff working area in winter in Qingdao. The temperature is affected obviously by the piston wind from the train and waiting hall in the lower Hall, and the temperature is not satisfied with the least heat comfort temperature of 16 °C. At the same time, the heat produced by the electrical and control equipments is brought by the cooling air to atmosphere for the equipment safety. Utilizing the water-circulating heat pump, it is feasible to transfer the emission heat to the staff working area to improve the thermal environment. Analyzed the feasibility from the technique and economy when using the heat pump, the water-circulating heat pump could be the best way to realize the waste heat recovery and to help the heat comfort of staff working area in winter in the underground metro station in north China.

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-07-01

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

Industrial furnace with improved heat transfer

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1993-07-20

A method is described for effecting improved heat transfer with in an industrial furnace having a cylindrical furnace section, a door at one end of the furnace section, an end plate at the opposite end of the section a circular fan plate concentrically positioned within the furnace section to define a cylindrical fan chamber between the plate and the end section with a fan there between and a heat treat chamber between the plate and the door, the fan plate defining a non-orificing annular space extending between the interior of the cylindrical furnace section and the outer edge of the plate, the plate having a centrally located under-pressure opening extending there through and a plurality of circumferentially spaced tubular heating elements extending through the annular space into the heat treating chamber, the method comprising the steps of: (a) heating the heating elements to a temperature which is hotter that the temperature of the work within the heat treating chamber; (b) rotating the fan at a speed sufficient to form a portion of the furnace atmosphere as a wind mass swirling about the fan chamber; (c) propagating the wind mass through the annular space into the heat treating chamber as a swirling wind mass in the form of an annulus, the wind mass impinging the heating elements to establish heat transfer contact therewith while the mass retains its annulus shape until contacting the door and without any significant movement of the wind mass into the center of the heat treating chamber; (d) drawing the wind mass through the under-pressure zone after the wind mass comes into heat transfer contact with the work in the heat treating chamber; and (e) thereafter heating the work by radiation from the beating elements at high furnace temperatures in excess of about 1,600 F.

Review on advanced of solar assisted chemical heat pump dryer for agriculture produce

International Nuclear Information System (INIS)

Fadhel, M.I.; Sopian, K.; Daud, W.R.W.; Alghoul, M.A.

2011-01-01

Over the past three decades there has been nearly exponential growth in drying R and D on a global scale. Improving of the drying operation to save energy, improve product quality as well as reduce environmental effect remained as the main objectives of any development of drying system. A solar assisted chemical heat pump dryer is a new solar drying system, which have contributed to better cost-effectiveness and better quality dried products as well as saving energy. A solar collector is adapted to provide thermal energy in a reactor so a chemical reaction can take place. This reduces the dependency of the drying technology on fossil energy for heating. In this paper a review on advanced of solar assisted chemical heat pump dryer is presented (the system model and the results from experimental studies on the system performance are discussed). The review of heat pump dryers and solar assisted heat pump dryer is presented. Description of chemical heat pump types and the overview of chemical heat pump dryer are discussed. The combination of chemical heat pump and solar technology gives extra efficiency in utilizing energy. (author)

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

Comparative Effectiveness of Different Phase Change Materials to Improve Cooling Performance of Heat Sinks for Electronic Devices

Directory of Open Access Journals (Sweden)

Ahmad Hasan

2016-08-01

Full Text Available This paper thermo-physically characterizes salt hydrate, paraffin wax and milk fat as phase change materials (PCMs. The three PCMs are compared in terms of improving heat sink (HS performance for cooling electronic packaging. An experimental study is carried out on commercially available finned HS with and without PCM under natural ventilation (NV and forced ventilation (FV at different heat loads (4 W to 10 W. The results indicate that integration of all of the PCMs into the HS improves its cooling performance; however, milk fat lags behind the other two PCMs in terms of cooling produced. A three-dimensional pressure-based conjugate heat transfer model has been developed and validated with experimental results. The model predicts the parametric influence of PCM melting range, thermal conductivity and density on HS thermal management performance. The HS cooling performance improves with increased density and conductivity while it deteriorates with the wider melting range of the PCMs.

Methods of producing alkylated hydrocarbons from an in situ heat treatment process liquid

Science.gov (United States)

Roes, Augustinus Wilhelmus Maria [Houston, TX; Mo, Weijian [Sugar Land, TX; Muylle, Michel Serge Marie [Houston, TX; Mandema, Remco Hugo [Houston, TX; Nair, Vijay [Katy, TX

2009-09-01

A method for producing alkylated hydrocarbons is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce at least a second gas stream including hydrocarbons having a carbon number of at least 3. The first gas stream and the second gas stream are introduced into an alkylation unit to produce alkylated hydrocarbons. At least a portion of the olefins in the first gas stream enhance alkylation.

A study of the flow boiling heat transfer in a minichannel for a heated wall with surface texture produced by vibration-assisted laser machining

International Nuclear Information System (INIS)

Piasecka, Magdalena; Strąk, Kinga; Grabas, Bogusław; Maciejewska, Beata

2016-01-01

The paper presents results concerning flow boiling heat transfer in a vertical minichannel with a depth of 1.7 mm and a width of 16 mm. The element responsible for heating FC-72, which flowed laminarly in the minichannel, was a plate with an enhanced surface. Two types of surface textures were considered. Both were produced by vibration-assisted laser machining. Infrared thermography was used to record changes in the temperature on the outer smooth side of the plate. Two-phase flow patterns were observed through a glass pane. The main aim of the study was to analyze how the two types of surface textures affect the heat transfer coefficient. A two-dimensional heat transfer approach was proposed to determine the local values of the heat transfer coefficient. The inverse problem for the heated wall was solved using a semi-analytical method based on the Trefftz functions. The results are presented as relationships between the heat transfer coefficient and the distance along the minichannel length and as boiling curves. The experimental data obtained for the two types of enhanced heated surfaces was compared with the results recorded for the smooth heated surface. The highest local values of the heat transfer coefficient were reported in the saturated boiling region for the plate with the type 1 texture produced by vibration-assisted laser machining. (paper)

Electromagnetic heating method to improve steam assisted gravity drainage

Energy Technology Data Exchange (ETDEWEB)

Koolman, M.; Huber, N.; Diehl, D.; Wacker, B. [Siemens AG, Munich (Germany)

2008-10-15

The in-situ recovery of heavy and highly viscous bitumen has become economically feasible with the use of steam assisted gravity drainage (SAGD). However, several challenges exist, such as the energy cost for production of bitumen; environmental concerns over the consumption of water; limited recovery of bitumen; shallowness of the reservoirs; and the propagation of steam chambers leading to limited recovery. This paper described an opportunity to improve the widely applied SAGD process for in-situ production of bitumen from oil sands deposits. The technical concept was directed at electromagnetic (EM-SAGD) heating methods assisting the process. The paper described a preliminary investigation that was conducted in order to confirm the feasibility of different solutions and evaluate aspects of energy efficiency and environmental impact. A comparison of electrical heating methods showed that the inductive method was the most reasonable in terms of technical and economical feasibility. The paper also discussed a small scale sandbox test to verify a three-dimensional simulation provided with two different simulation tools. The results of reservoir simulation were also presented. Last, the paper examined health and safety considerations. It was concluded that inductive heating provides an additional, easy to handle control parameter. The study showed that if the geometries of the inductors related to the producer wells were selected in a tailor-made manner, individual reservoir conditions could be handled by an optimized operating strategy. 4 refs., 3 tabs., 15 figs.

Combined Space and Water Heating: Next Steps to Improved Performance

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

2016-07-13

A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%–4.3% (20–40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes. The full modulation control showed additional savings over set point control (in high-load homes almost doubling the savings: 4%–5% over the no-control case). At the time of installation the reset control can be implemented for $200–$400, which would provide paybacks of 6–25 years for low-load houses and 3–15 years for high-load houses. Full modulation implementation costs would be similar to the outdoor reset and would provide paybacks of 5-½–20 years for low-load houses and 2-½–10 years for high-load houses.

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

Residual stress improvement for pipe weld by means of induction heating pre-flawed pipe

International Nuclear Information System (INIS)

Umemoto, T.; Yoshida, K.; Okamoto, A.

1980-01-01

The intergranular stress corrosion cracking (IGSCC) has been found in type 304 stainless steel piping of several BWR plants. It is already well known that IGSCC is most likely to occur when three essential factors, material sensitization, high tensile stress and corrosive environment, are present. If the welding residual stress is sufficiently high (200 to approximately 400 MPa) in the inside piping surface near the welded joint, then it may be one of the biggest contributors to IGSCC. If the residual stress is reduced or reversed by some way, the IGSCC will be effectively mitigated. In this paper a method to improve the residual stress named IHSI (Induction Heating Stress Improvement) is explained. IHSI aims to improve the condition of residual stress in the inside pipe surface using the thermal stress induced by the temperature difference in pipe wall, that is produced when the pipe is heated from the outside surface by an induction heating coil and cooled on the inside surface by water simultaneously. This method becomes more attractive when it can be successfully applied to in-service piping which might have some pre-flaw. In order to verify the validity of IHSI for such piping, some experiments and calculations using finite element method were conducted. These results are mainly discussed in this paper from the view-points of residual stress, flaw behaviour during IHSI and material deterioration. (author)

Improvements of reforming performance of a nuclear heated steam reforming process

International Nuclear Information System (INIS)

Hada, Kazuhiko

1996-10-01

Performance of an energy production process by utilizing high temperature nuclear process heat was not competitive to that by utilizing non-nuclear process heat, especially fossil-fired process heat due to its less favorable chemical reaction conditions. Less favorable conditions are because a temperature of the nuclear generated heat is around 950degC and the heat transferring fluid is the helium gas pressurized at around 4 MPa. Improvements of reforming performance of nuclear heated steam reforming process were proposed in the present report. The steam reforming process, one of hydrogen production processes, has the possibility to be industrialized as a nuclear heated process as early as expected, and technical solutions to resolve issues for coupling an HTGR with the steam reforming system are applicable to other nuclear-heated hydrogen production systems. The improvements are as follows: As for the steam reformer, (1) increase in heat input to process gas by applying a bayonet type of reformer tubes and so on, (2) increase in reforming temperature by enhancing heat transfer rate by the use of combined promoters of orifice baffles, cylindrical thermal radiation pipes and other proposal, and (3) increase in conversion rate of methane to hydrogen by optimizing chemical compositions of feed process gas. Regarding system arrangement, a steam generator and superheater are set in the helium loop as downstream coolers of the steam reformer, so as to effectively utilize the residual nuclear heat for generating feed steam. The improvements are estimated to achieve the hydrogen production rate of approximately 3800 STP-m 3 /h for the heat source of 10 MW and therefore will provide the potential competitiveness to a fossil-fired steam reforming process. Those improvements also provide the compactness of reformer tubes, giving the applicability of seamless tubes. (J.P.N.)

WAD, a program to calculate the heat produced by alpha decay

International Nuclear Information System (INIS)

Jarvis, R.G.; Bretzlaff, C.I.

1982-09-01

The FORTRAN program WAD (Watts from Alpha Decay) deals with the alpha and beta decay chains to be encountered in advanced fuel cycles for CANDU reactors. The data library covers all necessary alpha-emitting and beta-emitting nuclides and the program calculates the heat produced by alpha decay. Any permissible chain can be constructed very simply

Improved reliability of residential heat pumps; Foerbaettrad driftsaekerhet hos villavaermepumpar

Energy Technology Data Exchange (ETDEWEB)

Haglund Stignor, Caroline; Larsson, Kristin; Jensen, Sara; Larsson, Johan; Berg, Johan; Lidbom, Peter; Rolfsman, Lennart

2012-07-01

Today, heat pump heating systems are common in Swedish single-family houses. Many owners are pleased with their installation, but statistics show that a certain number of heat pumps break every year, resulting in high costs for both insurance companies and owners. On behalf of Laensfoersaekringars Forskningsfond, SP Energy Technology has studied the cause of the most common failures for residential heat pumps. The objective of the study was to suggest what measures to be taken to reduce the number of failures, i.e. improving the reliability of heat pumps. The methods used were analysis of public failure statistics and sales statistics and interviews with heat pump manufacturers, installers, service representatives and assessors at Laensfoersaekringar. In addition, heat pump manuals have been examined and literature searches for various methods for durability tests have been performed. Based on the outcome from the interviews the most common failures were categorized by if they; 1. Could have been prevented by better operation and maintenance of the heat pump. 2. Caused by a poorly performed installation. 3. Could have been prevented if certain parameters had been measured, recorded and followed up. 4. Are due to poor quality of components or systems. However, the results show that many of the common failures fall into several different categories and therefore, different types of measures must be taken to improve the operational reliability of residential heat pumps. The interviews tell that failures often are caused by poor installation, neglected maintenance and surveillance, and poor quality of standard components or that components are used outside their declared operating range. The quality of the installations could be improved by increasing installers' knowledge about heat pumps and by requiring that an installation protocol shall be filled-in. It is also important that the owner of the heat pump performs the preventive maintenance recommended by the

Improved reliability of residential heat pumps; Foerbaettrad driftsaekerhet hos villavaermepumpar

Energy Technology Data Exchange (ETDEWEB)

Haglund Stignor, Caroline; Larsson, Kristin; Jensen, Sara; Larsson, Johan; Berg, Johan; Lidbom, Peter; Rolfsman, Lennart

2012-07-01

Today, heat pump heating systems are common in Swedish single-family houses. Many owners are pleased with their installation, but statistics show that a certain number of heat pumps break every year, resulting in high costs for both insurance companies and owners. On behalf of Laensfoersaekringars Forskningsfond, SP Energy Technology has studied the cause of the most common failures for residential heat pumps. The objective of the study was to suggest what measures to be taken to reduce the number of failures, i.e. improving the reliability of heat pumps. The methods used were analysis of public failure statistics and sales statistics and interviews with heat pump manufacturers, installers, service representatives and assessors at Laensfoersaekringar. In addition, heat pump manuals have been examined and literature searches for various methods for durability tests have been performed. Based on the outcome from the interviews the most common failures were categorized by if they; 1. Could have been prevented by better operation and maintenance of the heat pump. 2. Caused by a poorly performed installation. 3. Could have been prevented if certain parameters had been measured, recorded and followed up. 4. Are due to poor quality of components or systems. However, the results show that many of the common failures fall into several different categories and therefore, different types of measures must be taken to improve the operational reliability of residential heat pumps. The interviews tell that failures often are caused by poor installation, neglected maintenance and surveillance, and poor quality of standard components or that components are used outside their declared operating range. The quality of the installations could be improved by increasing installers' knowledge about heat pumps and by requiring that an installation protocol shall be filled-in. It is also important that the owner of the heat pump performs the preventive maintenance recommended by the

Improving the performance of booster heat pumps using zeotropic mixtures

DEFF Research Database (Denmark)

Zühlsdorf, B.; Meesenburg, W.; Ommen, T. S.

2018-01-01

Abstract This study demonstrated an increase in the thermodynamic performance of a booster heat pump, which was achieved by choosing the working fluid among pure and mixed fluids. The booster heat pump was integrated in an ultra-low-temperature district heating network with a forward temperature...... of 40 °C to produce domestic hot water, by heating part of the forward stream to 60 °C, while cooling the remaining part to the return temperature of 25 °C. The screening of working fluids considered 18 pure working fluids and all possible binary mixtures of these fluids. The most promising solutions...... heat supply system while being economically competitive to pure fluids....

Base fluid in improving heat transfer for EV car battery

Science.gov (United States)

Bin-Abdun, Nazih A.; Razlan, Zuradzman M.; Shahriman, A. B.; Wan, Khairunizam; Hazry, D.; Ahmed, S. Faiz; Adnan, Nazrul H.; Heng, R.; Kamarudin, H.; Zunaidi, I.

2015-05-01

This study examined the effects of base fluid (as coolants) channeling inside the heat exchanger in the process of the increase in thermal conductivity between EV car battery and the heat exchanger. The analysis showed that secondary cooling system by means of water has advantages in improving the heat transfer process and reducing the electric power loss on the form of thermal energy from batteries. This leads to the increase in the efficiency of the EV car battery, hence also positively reflecting the performance of the EV car. The present work, analysis is performed to assess the design and use of heat exchanger in increasing the performance efficiency of the EV car battery. This provides a preface to the use this design for nano-fluids which increase and improve from heat transfer.

Update heat exchanger designing principles

International Nuclear Information System (INIS)

Lipets, A.U.; Yampol'skij, A.E.

1985-01-01

Update heat exchanger design principles are analysed. Different coolant pattern in a heat exchanger are considered. It is suggested to rationally organize flow rates irregularity in it. Applying on heat exchanger designing measures on using really existing temperature and flow rate irregularities will permit to improve heat exchanger efficiency. It is expedient in some cases to artificially produce irregularities. In this connection some heat exchanger design principles must be reviewed now

Improved model for solar heating of buildings

OpenAIRE

Lie, Bernt

2015-01-01

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

Single Chain Variable Fragments Produced in Escherichia coli against Heat-Labile and Heat-Stable Toxins from Enterotoxigenic E. coli.

Directory of Open Access Journals (Sweden)

Christiane Y Ozaki

Full Text Available Diarrhea is a prevalent pathological condition frequently associated to the colonization of the small intestine by enterotoxigenic Escherichia coli (ETEC strains, known to be endemic in developing countries. These strains can produce two enterotoxins associated with the manifestation of clinical symptoms that can be used to detect these pathogens. Although several detection tests have been developed, minimally equipped laboratories are still in need of simple and cost-effective methods. With the aim to contribute to the development of such diagnostic approaches, we describe here two mouse hybridoma-derived single chain fragment variable (scFv that were produced in E. coli against enterotoxins of ETEC strains.Recombinant scFv were developed against ETEC heat-labile toxin (LT and heat-stable toxin (ST, from previously isolated hybridoma clones. This work reports their design, construction, molecular and functional characterization against LT and ST toxins. Both antibody fragments were able to recognize the cell-interacting toxins by immunofluorescence, the purified toxins by ELISA and also LT-, ST- and LT/ST-producing ETEC strains.The developed recombinant scFvs against LT and ST constitute promising starting point for simple and cost-effective ETEC diagnosis.

Improved heat transfer modeling of the eye for electromagnetic wave exposures.

Science.gov (United States)

Hirata, Akimasa

2007-05-01

This study proposed an improved heat transfer model of the eye for exposure to electromagnetic (EM) waves. Particular attention was paid to the difference from the simplified heat transfer model commonly used in this field. From our computational results, the temperature elevation in the eye calculated with the simplified heat transfer model was largely influenced by the EM absorption outside the eyeball, but not when we used our improved model.

Improved confinement during ICRF heating on JFT-2M

International Nuclear Information System (INIS)

Matsumoto, Hiroshi; Ogawa, Toshihide; Tamai, Hiroshi

1986-10-01

Significant improvement of energy confinement was observed on JFT-2M during ICRF heating. This improvement is associated with the sudden depression of H α /D α emission and the following increase of plasma stored energy, electron density and the radiation loss. This should be the same phenomena as H-mode transitions observed in ASDEX, PDX, and D-III divertor experiments with neutral beam injection heating. However, this transition is also observed in limiter discharges as well as in open divertor configurations on JFT-2M. (author)

An Experiment on Heat Recovery Performance Improvements in Well-Water Heat-Pump Systems for a Traditional Japanese House

Directory of Open Access Journals (Sweden)

Chiemi Iba

2018-04-01

Full Text Available Concerns about resource depletion have prompted several countries to promote the usage of renewable energy, such as underground heat. In Japan, underground heat-pump technology has begun to be utilized in large-scale office buildings; however, several economic problems are observed to still exist, such as high initial costs that include drilling requirements. Further, most of the traditional dwellings “Kyo-machiya” in Kyoto, Japan have a shallow well. This study intends to propose an effective ground-source heat-pump system using the well water from a “Kyo-machiya” home that does not contain any drilling works. In previous research, it was depicted that the well-water temperature decreases as the heat pump (HP is operated and that the heat extraction efficiency steadily becomes lower. In this study, an experiment is conducted to improve efficiency using a drainage pump. Based on the experimental results, the effect of efficiency improvement and the increase in the electric power consumption of the drainage pump are examined. It is indicated that short-time drainage could help to improve efficiency without consuming excessive energy. Thus, continuous use of the heat pump becomes possible.

Investigation on Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

Improving Automation Routines for Automatic Heating Load Detection in Buildings

Directory of Open Access Journals (Sweden)

Stephen Timlin

2012-11-01

Full Text Available Energy managers use weather compensation data and heating system cut off routines to reduce heating energy consumption in buildings and improve user comfort. These routines are traditionally based on the calculation of an estimated building load that is inferred from the external dry bulb temperature at any point in time. While this method does reduce heating energy consumption and accidental overheating, it can be inaccurate under some weather conditions and therefore has limited effectiveness. There remains considerable scope to improve on the accuracy and relevance of the traditional method by expanding the calculations used to include a larger range of environmental metrics. It is proposed that weather compensation and automatic shut off routines that are commonly used could be improved notably with little additional cost by the inclusion of additional weather metrics. This paper examines the theoretical relationship between various external metrics and building heating loads. Results of the application of an advanced routine to a recently constructed building are examined, and estimates are made of the potential savings that can be achieved through the use of the routines proposed.

Characterization of biomass producer gas as fuel for stationary gas engines in combined heat and power production

DEFF Research Database (Denmark)

Ahrenfeldt, Jesper

2008-01-01

The aim of this project has been the characterization of biomass producer gas as a fuel for stationary gas engines in heat and power production. More than 3200 hours of gas engine operation, with producer gas as fuel, has been conducted at the biomass gasification combined heat and power (CHP...... different measuring methods. Likewise, no particles were detected in the gas. Considerable amounts of NH3 were measured in the produced gas.An analysis of engine operation at varying load has been carried out. Standard emissions, load and efficiency have been measured at varying operating conditions ranging...... from 50% to 90% load. Biomass producer gas is an excellent lean burn engine fuel: Operation of a natural aspirated engine has been achieved for 1.2...

The improvement of the heat transfer model for sodium-water reaction jet code

International Nuclear Information System (INIS)

Hashiguchi, Yoshirou; Yamamoto, Hajime; Kamoshida, Norio; Murata, Shuuichi

2001-02-01

For confirming the reasonable DBL (Design Base Leak) on steam generator (SG), it is necessary to evaluate phenomena of sodium-water reaction (SWR) in an actual steam generator realistically. The improvement of a heat transfer model on sodium-water reaction (SWR) jet code (LEAP-JET ver.1.40) and application analysis to the water injection tests for confirmation of propriety for the code were performed. On the improvement of the code, the heat transfer model between a inside fluid and a tube wall was introduced instead of the prior model which was heat capacity model including both heat capacity of the tube wall and inside fluid. And it was considered that the fluid of inside the heat exchange tube was able to treat as water or sodium and typical heat transfer equations used in SG design were also introduced in the new heat transfer model. Further additional work was carried out in order to improve the stability of the calculation for long calculation time. The test calculation using the improved code (LEAP-JET ver.1.50) were carried out with conditions of the SWAT-IR·Run-HT-2 test. It was confirmed that the SWR jet behavior on the result and the influence to the result of the heat transfer model were reasonable. And also on the improved code (LEAP-JET ver.1.50), user's manual was revised with additional I/O manual and explanation of the heat transfer model and new variable name. (author)

Improved process for the treatment of bituminous materials. [two heat treatments

Energy Technology Data Exchange (ETDEWEB)

1947-04-30

A continuous process for recovering valuable hydrocarbon oils from solid minerals adapted to produce such oils upon application of heat, consists of reducing the raw minerals to a powder, suspending the powdered minerals in a gaseous medium and subjecting the suspension thus formed to heat treatment in a primary reaction zone, followed by heat treatment in a secondary reaction zone separate from the primary reaction zone. The temperature during the second of said treatments being substantially higher than that of the first.

The technological raw material heating furnaces operation efficiency improving issue

Science.gov (United States)

Paramonov, A. M.

2017-08-01

The issue of fuel oil applying efficiency improving in the technological raw material heating furnaces by means of its combustion intensification is considered in the paper. The technical and economic optimization problem of the fuel oil heating before combustion is solved. The fuel oil heating optimal temperature defining method and algorithm analytically considering the correlation of thermal, operating parameters and discounted costs for the heating furnace were developed. The obtained optimization functionality provides the heating furnace appropriate thermal indices achievement at minimum discounted costs. The carried out research results prove the expediency of the proposed solutions using.

Modified heat treatment for lower temperature improvement of the mechanical properties of two ultrahigh strength low alloy steels

Science.gov (United States)

Tomita, Yoshiyuki; Okabayashi, Kunio

1985-01-01

In the previous papers, a new heat treatment for improving the lower temperature mechanical propertise of the ultrahigh strength low alloy steels was suggested by the authors which produces a mixed structure of 25 vol pct lower bainite and 75 vol pct martensite through isothermal transformation at 593 K for a short time followed by water quenching (after austenitization at 1133 K). In this paper, two commercial Japanese ultrahigh strength steels, 0.40 pct C-Ni-Cr-Mo (AISI 4340 type) and 0.40 pct C-Cr-Mo (AISI 4140 type), have been studied to determine the effect of the modified heat treatment, coupled above new heat treatment with γ ⇆ α' repctitive heat treatment, on the mechanical properties from ambient temperature (287 K) to 123 K. The results obtained for various test temperatures have been compared with those for the new heat treatment reported previously and the conventional 1133 K direct water quenching treatment. The incorporation of intermediate four cyclic γ ⇆ α' repctitive heat treatment steps (after the initial austenitization at 1133 K and oil quenching) into the new heat treatment reported previously, as compared with the conventional 1133 K direct water quenching treatment, significantly improved 0.2 pct proof stress as well as notch toughness of the 0.40 pct C-Ni-Cr-Mo ultrahigh strength steel at similar fracture ductility levels from 287 to 123 K. Also, this heat treatment, as compared with the conventional 1133 K direct water quenching treatment, significantly improved both 0.2 pct proof stress and notch toughness of the 0.40 pct C-Cr-Mo ultrahigh strength steel with increased fracture ductility at 203 K and above. The microstructure consists of mixed areas of ultrafine grained martensite, within which is the refined blocky, highly dislocated structure, and the second phase lower bainite (about 15 vol pct), which appears in acicular form and partitions prior austenite grains. This newly developed heat treatment makes it possible to modify

Heat transfer improvement due to the imposition of non-uniform wall heating for in-tube laminar forced convection

International Nuclear Information System (INIS)

Hajmohammadi, M.R.; Poozesh, S.; Rahmani, M.; Campo, A.

2013-01-01

This paper explores the bearing that a non-uniform distribution of heat flux used as a wall boundary condition exerts on the heat transfer improvement in a round pipe. Because the overall heat load is considered fixed, the heat transfer improvement is viewed through a reduction in the maximum temperature (‘hot spot’) by imposing optimal distribution of heat flux. Two cases are studied in detail 1) fully developed and 2) developing flow. Peak temperatures in the heated pipe wall are calculated via an analytical approach for the fully developed case, while a numerical simulation based on CFD is employed for the developing case. By relaxing the heat flux distribution on the pipe wall, the numerical results imply that the optimum distribution of heat flux, which minimizes the peak temperatures corresponds with the ‘descending’ distribution. Given that the foregoing approach is quite different from the ‘ascending’ heat flux distribution recommended in the literature by means of the entropy generation minimization (EGM) method, it is inferred that the optimization of heat transfer and fluid flow, in comparison with the thermodynamic optimization, may bring forth quite different guidelines for the designs of thermal systems under the same constraints and circumstances. -- Highlights: • Considered the bearing of non-uniform distribution of heat flux on the hot spots. • Determined the optimal distribution of heat flux that minimizes the hot spots. • Results are compared with those obtained by EGM method

Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia

Directory of Open Access Journals (Sweden)

KAVEH RAHMANIFARAH

2014-05-01

Full Text Available Rahmanifarah K, Shabanpour B, Shaviklo AR, Aalami M. 2014. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia. Nusantara Bioscience 6: 1-6. The effect of protein extraction procedures (leached mince and heated suspension on selected properties of fish protein powder (proximate composition, pH, color, density, viscosity, fat adsorption, emulsifying capacity, emulsifying stability, foaming capacity, foaming stability, WBC, protein solubility in water, hygroscopicity, Trichloroacetic acid (TCA-soluble peptides and free sulfhydryl groups was investigated. Results showed that Fish protein powder (FPP produced by leaching mince (LM have higher protein, moisture, ash, pH, L*, viscosity, emulsion capacity, emulsion stability, foam capacity, foam stability, water binding capacity (WBC, protein solubility, hygroscopicity, TCA soluble peptides and free sulfhydryl group content than heated suspension (HS (P0.05. Overall, it was observed that high temperature during heating of suspension in HS method makes possible protein denaturation and aggregation. Consequently, based on functional, chemical and physical properties, extraction of fish protein by leaching process was found to be suitable for the production of fish protein powder.

An improved routine for the fast estimate of ion cyclotron heating efficiency in tokamak plasmas

International Nuclear Information System (INIS)

Brambilla, M.

1992-02-01

The subroutine ICEVAL for the rapid simulation of Ion Cyclotron Heating in tokamak plasmas is based on analytic estimates of the wave behaviour near resonances, and on drastic but reasonable simplifications of the real geometry. The subroutine has been rewritten to improve the model and to facilitate its use as input in transport codes. In the new version the influence of quasilinear minority heating on the damping efficiency is taken into account using the well-known Stix analytic approximation. Among other improvements are: a) the possibility of considering plasmas with more than two ion species; b) inclusion of Landau, Transit Time and collisional damping on the electrons non localised at resonances; c) better models for the antenna spectrum and for the construction of the power deposition profiles. The results of ICEVAL are compared in detail with those of the full-wave code FELICE for the case of Hydrogen minority heating in a Deuterium plasma; except for details which depend on the excitation of global eigenmodes, agreement is excellent. ICEVAL is also used to investigate the enhancement of the absorption efficiency due to quasilinear heating of the minority ions. The effect is a strongly non-linear function of the available power, and decreases rapidly with increasing concentration. For parameters typical of Asdex Upgrade plasmas, about 4 MW are required to produce a significant increase of the single-pass absorption at concentrations between 10 and 20%. (orig.)

Improving MODPRESS heat loss calculations for PWR pressurizers

International Nuclear Information System (INIS)

Ramos, Natalia V.; Lira, Carlos A. Brayner O.; Castrillho, Lazara S.

2009-01-01

The improvement of heat loss calculations in MODPRESS transient code for PWR pressurizer analysis is the main focus of this investigation. Initially, a heat loss model was built based on heat transfer coefficient (HTC) correlations obtained in handbooks of thermal engineering. A hand calculation for Neptunus experimental test number U47 yielded a thermal power loss of 11.2 kW against 17.3 kW given by MODPRESS at the same conditions, while the experimental estimate is given as 17 kW. This comparison is valid only for steady state or before starting the transient experiment, because MODPRESS does not update HTC's when the transient phase begins. Furthermore, it must be noted that MODPRESS heat transfer coefficients are adjusted to reproduce the experimental value of the specific type of pressurizer. After inserting the new routine for HTC's into MODPRESS, the heat loss was calculated as 11.4 kW, a value very close to the first estimate but far below 17 kW found in the U47 experiment. In this paper, the heat loss model and results will be described. Further research is being developed to find a more general HTC that allows the analysis of the effects of heat losses on transient behavior of Neptunus and IRIS pressurizers. (author)

How can we constrain the amount of heat producing elements in the interior of Mars?

Science.gov (United States)

Grott, M.; Plesa, A.; Breuer, D.

2013-12-01

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission to be launched in 2016 will study Mars' deep interior and help improving our knowledge about the interior structure and the thermal evolution of the planet - the latter is also directly linked to its volcanic history and atmospheric evolution. Measurements planned with the two main instruments, SEIS (Seismic Experiment for Interior Structure) and HP3 (Heat Flow and Physical Properties Package) aim to constrain the main structure of the planet, i.e. core, mantle and crust as well as the rate at which the planet loses the interior heat over its surface. Since the surface heat flow depends on the amount of radiogenic heat elements (HPE) present in the interior, it offers a measurable quantity which could constrain the heat budget. Being the principal agent regulating the heat budget which in turn influences partial melting in the interior, crustal and atmospheric evolution, the heat producing elements have a major impact on the entire the present temperature thermal history of the planet. To constrain the radiogenic heat elements of the planet from the surface heat flow is possible assuming that the urey number of the planet, which describes the contribution of internal heat production to the surface heat loss, is known. We have tested this assumption by calculating the thermal evolution of the planet with fully dynamical numerical simulations and by comparing the obtained present-day urey number for a set of different models/parameters (Fig. 1). For one-plate planets like Mars, numerical models show - in contrast to models for the Earth, where plate tectonics play a major role adding more complexity to the system - that the urey ratio is mainly sensitive to two effects: the efficiency of cooling due to the temperature-dependence of the viscosity and the mean half-life time of the long lived radiogenic isotopes. The temperature-dependence of the viscosity results in the

New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

International Nuclear Information System (INIS)

Qu, Ming; Abdelaziz, Omar; Yin, Hongxi

2014-01-01

Highlights: • Thermal and heat transfer models of absorption heat pumps driven by exhaust gas, hot water, or natural gas. • Natural gas boiler combustion model. • Heat exchanger for condensing. • Experimental data of a hot water absorption heat pump. • Economic assessment of heat recovery absorption heat pump for improving natural gas boilers. - Abstract: Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150–200 °C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50–60 °C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural

achieving improved financing for low-income producers

African Journals Online (AJOL)

KEY WORDS: Approaches, Improved Access, Finance, Low-income, Producers. INTRODUCTION .... either by setting up a dual-purpose financial institution, or by making ..... management information systems (Braverman and. Huppi, 1991).

Heating entrepreneurship in Finland. Final report

International Nuclear Information System (INIS)

Tuomi, S.

1998-01-01

The aim of the project was to improve the feasibility of the various forms of heating entrepreneurship and to launch new heating enterprises. The project was carried out by the TTS Institute as part of the national Bioenergy Research Programme. Feasibility was studied both from the viewpoint of the entrepreneurs and of municipalities. Feasibility was improved by developing production chains in the field of heating entrepreneurship and the operability of heating plants. Establishment of new heating enterprises was promoted by producing and disseminating information to potential entrepreneurs and municipalities. The feasibility of heating entrepreneurship was studied at ten enterprises. Information was gathered by resorting to daily bookkeeping and it concerned time usage in the various work stages, fuel consumption and the amount of heat produced. According to the results of the study, the profitability of the enterprises improved with increasing experience. The functional characteristics of heating plants were studied in the light of records maintained of failures and malfunction situations. Research data were also collected by evaluating the technical solutions of heating plants and by interviewing heating entrepreneurs and their customers. The economic impact of heating entrepreneurship from the viewpoint of municipalities was studied by interviewing eight entrepreneurs. All eight heating plants were slightly different. In addition to interviews, additional research data was collected by mailing questionnaires to municipalities. In the light of the responses received, municipalities were satisfied with the operation of the enterprises. Information-dissemination and training events were organised in co-operation with regional development and information organisations. Additionally, alternative ways to realise heating entrepreneurship were demonstrated both at exhibitions and trade fairs as well as at domestic and international seminars. Guiding material on heating

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.

Size distribution of salbutamol/ipratropium aerosols produced by different nebulizers in the absence and presence of heat and humidification.

Science.gov (United States)

Yang, Ssu-Han; Yang, Tsung-Ming; Lin, Hui-Ling; Tsai, Ying-Huang; Fang, Tien-Pei; Wan, Gwo-Hwa

2018-02-01

Few studies have evaluated the size distribution of inhaled and exhaled aerosolized drugs, or the effect of heated humidification on particle size and lung deposition. The present study evaluated these aspects of bronchodilator (salbutamol/ipratropium) delivery using a lung model in the absence and presence of heat and humidification. We positioned filters to collect and measure the initial drug, inhaled drug, and exhaled drug. Particle size distribution was evaluated using an 8-stage Marple personal cascade impactor with 0.2-μm polycarbonate filters. A greater inhaled drug mass was delivered using a vibrating mesh nebulizer (VMN) than by using a small volume nebulizer (SVN), when heated humidifiers were not employed. When heated and humidified medical gas was used, there was no significant difference between the inhaled drug mass delivered by the VMN and that delivered by the SVN. A significantly greater mass of inhaled 1.55-μm drug particles was produced by the VMN than with the SVN, under heated and humidified conditions. However, the mass median aerodynamic diameters (MMADs) of the aerosolized drug produced by the SVN and VMN did not differ significantly under the same conditions. The VMN produced more fine particles of salbutamol/ipratropium, and the drug particle size clearly increased in the presence of heat and humidification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improving the fatigue performance of porous metallic biomaterials produced by Selective Laser Melting.

Science.gov (United States)

Van Hooreweder, Brecht; Apers, Yanni; Lietaert, Karel; Kruth, Jean-Pierre

2017-01-01

This paper provides new insights into the fatigue properties of porous metallic biomaterials produced by additive manufacturing. Cylindrical porous samples with diamond unit cells were produced from Ti6Al4V powder using Selective Laser Melting (SLM). After measuring all morphological and quasi-static properties, compression-compression fatigue tests were performed to determine fatigue strength and to identify important fatigue influencing factors. In a next step, post-SLM treatments were used to improve the fatigue life of these biomaterials by changing the microstructure and by reducing stress concentrators and surface roughness. In particular, the influence of stress relieving, hot isostatic pressing and chemical etching was studied. Analytical and numerical techniques were developed to calculate the maximum local tensile stress in the struts as function of the strut diameter and load. With this method, the variability in the relative density between all samples was taken into account. The local stress in the struts was then used to quantify the exact influence of the applied post-SLM treatments on the fatigue life. A significant improvement of the fatigue life was achieved. Also, the post-SLM treatments, procedures and calculation methods can be applied to different types of porous metallic structures and hence this paper provides useful tools for improving fatigue performance of metallic biomaterials. Additive Manufacturing (AM) techniques such as Selective Laser Melting (SLM) are increasingly being used for producing customized porous metallic biomaterials. These biomaterials are regularly used for biomedical implants and hence a long lifetime is required. In this paper, a set of post-built surface and heat treatments is presented that can be used to significantly improve the fatigue life of porous SLM-Ti6Al4V samples. In addition, a novel and efficient analytical local stress method was developed to accurately quantify the influence of the post

The effect of postproduction heat treatment on γ-TiAl alloys produced by the GTAW-based additive manufacturing process

Energy Technology Data Exchange (ETDEWEB)

Ma, Yan; Cuiuri, Dominic; Li, Huijun; Pan, Zengxi, E-mail: zengxi@uow.edu.au; Shen, Chen

2016-03-07

Postproduction heat treatments were carried out on additively manufactured γ-TiAl alloys that were produced by using the gas tungsten arc welding (GTAW) process. The microstructural evolution and mechanical properties of both as-fabricated and heat-treated specimens were investigated to assess the effect of different heat treatment conditions, by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Neutron Diffraction and tensile tests. The results indicated that heat treatment promotes the formation of the γ phase in the majority region after heat treatment at 1200 °C for 24 h, while a fully lamellar structure was formed in the near-substrate zone. The response to heat treatment at 1060 °C/24 h was markedly different, producing a fine lamellar structure with differing sizes in the majority region and near-substrate zone. These various microstructural characteristics determined the mechanical properties of the heat-treated samples. The heat-treated samples at 1200 °C/24 h exhibited lower UTS and microhardness values but higher ductility than the as-fabricated samples without heat treatment, while the 1060 °C/24 h heat treatment resulted in higher UTS and microhardness values but lower ductility. Due to the homogenous microstructure in the majority region after each postproduction heat treatment, the tensile properties were similar for both the build direction (Z) and travel direction (Y), thereby minimising the anisotropy that is exhibited by the as-fabricated alloy prior to heat treatment.

Characteristics of plasma in uranium atomic beam produced by electron-beam heating

International Nuclear Information System (INIS)

Ohba, Hironori; Shibata, Takemasa

2000-08-01

The electron temperature of plasma and the ion flux ratio in the uranium atomic beam produced by electron-beam heating were characterized with Langmuir probes. The electron temperature was 0.13 eV, which was lower than the evaporation surface temperature. The ion flux ratio to atomic beam flux was more than 3% at higher evaporation rates. The ion flux ratio has increased with decreasing acceleration energy of the electron-beam under constant electron-beam power. This is because of an increase of electron-beam current and a large ionization cross-section of uranium by electron-impact. It was confined that the plasma is produced by electron-impact ionization of the evaporated atoms at the evaporation source. (author)

Acute limb heating improves macro- and microvascular dilator function in the leg of aged humans.

Science.gov (United States)

Romero, Steven A; Gagnon, Daniel; Adams, Amy N; Cramer, Matthew N; Kouda, Ken; Crandall, Craig G

2017-01-01

Local heating of an extremity increases blood flow and vascular shear stress throughout the arterial tree. Local heating acutely improves macrovascular dilator function in the upper limbs of young healthy adults through a shear stress-dependent mechanism but has no such effect in the lower limbs of this age group. The effect of acute limb heating on dilator function within the atherosclerotic prone vasculature of the lower limbs of aged adults is unknown. Therefore, the purpose of this study was to test the hypothesis that acute lower limb heating improves macro- and microvascular dilator function within the leg vasculature of aged adults. Nine young and nine aged adults immersed their lower limbs at a depth of ~33 cm into a heated (~42°C) circulated water bath for 45 min. Before and 30 min after heating, macro (flow-mediated dilation)- and microvascular (reactive hyperemia) dilator functions were assessed in the lower limb, following 5 min of arterial occlusion, via Doppler ultrasound. Compared with preheat, macrovascular dilator function was unchanged following heating in young adults (P = 0.6) but was improved in aged adults (P = 0.04). Similarly, microvascular dilator function, as assessed by peak reactive hyperemia, was unchanged following heating in young adults (P = 0.1) but was improved in aged adults (P lower limb heating improves both macro- and microvascular dilator function in an age dependent manner. We demonstrate that lower limb heating acutely improves macro- and microvascular dilator function within the atherosclerotic prone vasculature of the leg in aged adults. These findings provide evidence for a potential therapeutic use of chronic lower limb heating to improve vascular health in primary aging and various disease conditions. Copyright © 2017 the American Physiological Society.

Improvement of Candu-1000 MW(e) power cycle by moderator heat recovery

International Nuclear Information System (INIS)

Fath, H.E.S.

1988-01-01

Four different moderator heat recovery circuits are proposed for CANDU-1000 MW(e) reactors. The proposed circuits utilize all, or part, of the 155 MW(th) moderator heat load (at 70 0 C moderator outlet temperature from calandria) to the first stage of the feed water heating system. An economics study was carried out and indicated that the direct circulation of feed water through the moderator heat exchanger (with full heat recovery) is the most economical scheme. For this scheme the saved steam from the turbine extraction was found to produce additional electric power of 8 MW(e). This additional power represents a 0.7% increase in the plants nominal electric output. The outstanding features and advantages of the selected scheme are also presented. (author)

HEAT TRANSFER METHOD

Science.gov (United States)

Gambill, W.R.; Greene, N.D.

1960-08-30

A method is given for increasing burn-out heat fluxes under nucleate boiling conditions in heat exchanger tubes without incurring an increase in pumping power requirements. This increase is achieved by utilizing a spinning flow having a rotational velocity sufficient to produce a centrifugal acceleration of at least 10,000 g at the tube wall. At this acceleration the heat-transfer rate at burn out is nearly twice the rate which can be achieved in a similar tube utilizing axial flow at the same pumping power. At higher accelerations the improvement over axial flow is greater, and heat fluxes in excess of 50 x 10/sup 6/ Btu/hr/sq ft can be achieved.

District heating development, air quality improvement, and cogeneration in Krakow, Poland

International Nuclear Information System (INIS)

Manczyk, H.; Leach, M.D.

1992-01-01

Krakow, Poland, is served by a district heating system that includes coal-fired electrical and heating plants and distribution networks and by approximately 200,000 residential coal furnaces. Cogeneration facilities were added in the mid-1970s to supply up to 40% of the regional peak electrical demand and to optimize energy extraction from the low-heating-value coal mined in the region. Several difficulties prevent the district from realizing the potential efficiencies of its technology: the poor condition of the distribution network, the lack of consumption control and metering devices, inadequate plant maintenance, and the lack of economic incentives for operator productivity and energy conservation by users. Environmental concerns have caused the local government and international agencies to plan major improvements to the system. This paper discusses the development of the district heating system, coal use in Poland, cogeneration facilities, environmental concerns and pollution control plans, and improvement strategies

An H minority heating regime in Tore Supra showing improved L mode confinement

International Nuclear Information System (INIS)

Hoang, G.T.; Monier-Garbet, P.; Aniel, T.

2000-01-01

Tore Supra experiments are at present devoted to the study of high density regimes with radiofrequency heating. Recently, an improved L mode confinement regime has been observed in plasmas heated by ion cyclotron hydrogen minority heating, at relatively high densities up to 80% of the Greenwald limit. The quality of energy confinement is as good as that of ELMy H mode. The main physical mechanism of this regime has not been clearly identified. However, some features very similar to those of previous improved confinement modes using neutral beam heating in other tokamaks have been observed. (author)

Method of Heat Treating Aluminum-Lithium Alloy to Improve Formability

Science.gov (United States)

Chen, Po-Shou (Inventor); Russell, Carolyn Kurgan (Inventor)

2016-01-01

A method is provided for heat treating aluminum-lithium alloys to improve their formability. The alloy is heated to a first temperature, maintained at the first temperature for a first time period, heated at the conclusion of the first time period to a second temperature, maintained at the second temperature for a second time period, actively cooled at the conclusion of the second time period to a third temperature, maintained at the third temperature for a third time period, and then passively cooled at the conclusion of the third time period to room temperature.

Research on the Improvement of a Natural Gas Fired Burner for the CHP Application in a Central Heating Boiler using Radiant Burner Technology

Energy Technology Data Exchange (ETDEWEB)

Bieleveld, T.

2010-08-15

These days, the reduction of CO2 emissions from combustion devices is one of the main priorities for each design improvement. For the domestic use of the central heating boiler, Microgen Engine Corporation produces free piston Stirling engines for the Combined Heat and Power (CHP) application in these central heating boilers (Dutch: 'HRe ketel'). With CHP, the generation of electricity and heat are combined to increase overall efficiency, as heat is generally a waste product from the combustion to electric generation process. In this application, the Stirling engine, which can be defined as an external combustion engine, is heated by a natural gas fired engine-burner and cooled by a coolant flow. The heat transfer into the engine is converted into mechanical work and a heat flux from the engine. The mechanical work is used to produce electricity via a linear alternator. Heat in the flue gasses from the engine-burner is reused in a secondary burner and condensing heat exchanger. The coolant flow from the engine, after passing the secondary burner, is used for heating purposes. The heat transfer from engine-burner to the Stirling engine is analyzed and via several motivations it is found that it is favorable to improve fuel to electric conversion efficiency, for which the heat transfer efficiency of the engine-burner to the Stirling engine should be improved, as the engine design is not to be altered. From an initially developed linear free piston Stirling engine model and measurements performed at Microgen Engine Corporation, St. Petersborough, (UK), the engine power demand and engine-burner performance are found. The results are used to visualize the current energy flows of the Stirling engine and engine burner subsystem. The heat transfer to the engine is analyzed to find possible heat transfer improvements. It is concluded that heat transfer from the engine-burner to the engine can be approved if the flue losses due to convective heat transfer are

Improvement and validation of the wall heat transfer package of RELAP5/MOD3.3

International Nuclear Information System (INIS)

Wu, Pan; Xiong, Xiaofei; Shan, Jianqiang; Gou, Junli; Zhang, Bin; Zhang, Bo

2016-01-01

Highlights: • A new heat transfer package has been developed. • It has been incorporated into RELAP5/MOD3.3 to verify its advantages. • The results of modified code were compared with available experimental data. • The results showed that higher prediction accuracy was achieved. - Abstract: The process of energy transfer from heat structure to control volume is determined by the wall-to-fluid heat transfer package, which is crucial for nuclear reactor safety analysis codes. The current logic for selection of heat transfer modes of RELAP5/MOD3.3 code is too complex and may result in incorrect heat transfer mode judgment. Also, the narrow application scope of film boiling heat transfer correlations may result in large errors in film boiling region which is of paramount importance for the predicted peak clad temperatures during hypothetical LB-LOCAs in PWRs. In this study, a new heat transfer package has been developed and incorporated into the RELAP5/MOD3.3 code. Differing from the original package, the modified one consists of twelve heat transfer modes and proposes a new logic for selection of heat transfer modes. For each mode, the models in the existing safety analysis codes and the leading models in literature have been reviewed in order to determine the best model which can easily be applicable to the RELAP5/MOD3.3 code. Particularly (1) a new package of heat transfer correlations are produced; (2) a new logic for selection of film boiling and transition boiling heat transfer modes is proposed which use minimum film boiling temperature and critical heat flux temperature as distinguished points. The modified code has been validated by comparing the analysis results with available experimental data from tube post dryout experiments and loss-of-fluid test (LOFT) facility. The calculation results showed that the improved package could better predict the experimental phenomena with higher prediction accuracy.

Improvement and validation of the wall heat transfer package of RELAP5/MOD3.3

Energy Technology Data Exchange (ETDEWEB)

Wu, Pan; Xiong, Xiaofei; Shan, Jianqiang, E-mail: jqshan@mail.xjtu.edu.cn; Gou, Junli; Zhang, Bin; Zhang, Bo

2016-12-15

Highlights: • A new heat transfer package has been developed. • It has been incorporated into RELAP5/MOD3.3 to verify its advantages. • The results of modified code were compared with available experimental data. • The results showed that higher prediction accuracy was achieved. - Abstract: The process of energy transfer from heat structure to control volume is determined by the wall-to-fluid heat transfer package, which is crucial for nuclear reactor safety analysis codes. The current logic for selection of heat transfer modes of RELAP5/MOD3.3 code is too complex and may result in incorrect heat transfer mode judgment. Also, the narrow application scope of film boiling heat transfer correlations may result in large errors in film boiling region which is of paramount importance for the predicted peak clad temperatures during hypothetical LB-LOCAs in PWRs. In this study, a new heat transfer package has been developed and incorporated into the RELAP5/MOD3.3 code. Differing from the original package, the modified one consists of twelve heat transfer modes and proposes a new logic for selection of heat transfer modes. For each mode, the models in the existing safety analysis codes and the leading models in literature have been reviewed in order to determine the best model which can easily be applicable to the RELAP5/MOD3.3 code. Particularly (1) a new package of heat transfer correlations are produced; (2) a new logic for selection of film boiling and transition boiling heat transfer modes is proposed which use minimum film boiling temperature and critical heat flux temperature as distinguished points. The modified code has been validated by comparing the analysis results with available experimental data from tube post dryout experiments and loss-of-fluid test (LOFT) facility. The calculation results showed that the improved package could better predict the experimental phenomena with higher prediction accuracy.

Technical and economic assessment of producing hydrogen by reforming syngas from the Battelle indirectly heated biomass gasifier

International Nuclear Information System (INIS)

Mann, M.K.

1995-08-01

The technical and economic feasibility of producing hydrogen from biomass by means of indirectly heated gasification and steam reforming was studied. A detailed process model was developed in ASPEN Plus trademark to perform material and energy balances. The results of this simulation were used to size and cost major pieces of equipment from which the determination of the necessary selling price of hydrogen was made. A sensitivity analysis was conducted on the process to study hydrogen price as a function of biomass feedstock cost and hydrogen production efficiency. The gasification system used for this study was the Battelle Columbus Laboratory (BCL) indirectly heated gasifier. The heat necessary for the endothermic gasification reactions is supplied by circulating sand from a char combustor to the gasification vessel. Hydrogen production was accomplished by steam reforming the product synthesis gas (syngas) in a process based on that used for natural gas reforming. Three process configurations were studied. Scheme 1 is the full reforming process, with a primary reformer similar to a process furnace, followed by a high temperature shift reactor and a low temperature shift reactor. Scheme 2 uses only the primary reformer, and Scheme 3 uses the primary reformer and the high temperature shift reactor. A pressure swing adsorption (PSA) system is used in all three schemes to produce a hydrogen product pure enough to be used in fuel cells. Steam is produced through detailed heat integration and is intended to be sold as a by-product

Simulation of a combined heating, cooling and domestic hot water system based on ground source absorption heat pump

International Nuclear Information System (INIS)

Wu, Wei; You, Tian; Wang, Baolong; Shi, Wenxing; Li, Xianting

2014-01-01

Highlights: • A combined heating/cooling/DHW system based on GSAHP is proposed in cold regions. • The soil imbalance is effectively reduced and soil temperature can be kept stable. • 20% and 15% of condensation/absorption heat is recovered by GSAHP to produce DHW. • The combined system can improve the primary energy efficiency by 23.6% and 44.4%. - Abstract: The amount of energy used for heating and domestic hot water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) system based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP–GAX–HCD is suitable for Beijing and GSAHP–SE–HCD is suitable for Shenyang. The imbalance ratio can be reduced to −14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5 °C and 0.1 °C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling systems

Economy and development of heating station enterprises managed by forest owners

International Nuclear Information System (INIS)

Tuomi, S.

1997-01-01

Private heating enterprises are a new form of heat generation for municipalities in Finland. In this type the entrepreneur acquires the fuel and takes care of the operation and monitoring of the heating station. The recompense is paid on the basis of the heat amount produced to avoid problems related to i.e. the energy content and quality of the fuel. The price of heat is typically bound with that of light fuel oil. Agreements based on the price development of district heat and chips are also used. In 1996 there were 36 such heating enterprises in operation in Finland, their total efficiency being 11.5 MW. The aim of the project is to improve the feasibility of various forms of heating enterprises and to start new heating enterprises. The feasibility is studied both from the viewpoint of the entrepreneur and the municipality. The feasibility is improved by developing production chains of heating enterprises and the operability of the heating stations. Establishment of new heating enterprises is promoted by producing and disseminating information to possible entrepreneurs and municipalities. (orig.)

Economy and development of heating station enterprises managed by forest owners

International Nuclear Information System (INIS)

Tuomi, S.

1998-01-01

Private heating enterprises are a new form of heat generation for municipalities in Finland. In this type the entrepreneur acquires the fuel and takes care of the operation and monitoring of the heating station. The recompense is paid on the basis of the heat amount produced to avoid problems related to i.a. the energy content and quality of the fuel. The price of heat is typically bound with that of light fuel oil. Agreements based on the price development of district heat and chips are also used. In 1997 there were about 50 such heating enterprises in operation in Finland. The aim of the project is to improve the feasibility of various forms of heating enterprises and to start new heating enterprises. The feasibility is studied both from the viewpoint of the entrepreneur and the municipality. The feasibility is improved by developing production chains of heating enterprises and the operability of heating stations. Establishment of new heating enterprises is promoted by producing and disseminating information to possible entrepreneurs and municipalities. (orig.)

Process of producing fuels from slates or bituminous shales. [distillation at incandescent heat

Energy Technology Data Exchange (ETDEWEB)

Huppenbauer, M

1902-07-31

A process of producing a fuel from slates or bituminous shales by saturating or impregnating them after preliminary distillation with the vapors of tars, resins, oils, etc., is given. The process is characterized by the bituminous shale being submitted in the form of fragments to distillation at incandescent heat to make the shale porous and able to absorb the vapors of the substances already mentioned.

Heat Shock Protein 47: A Novel Biomarker of Phenotypically Altered Collagen-Producing Cells

International Nuclear Information System (INIS)

Taguchi, Takashi; Nazneen, Arifa; Al-Shihri, Abdulmonem A.; Turkistani, Khadijah A.; Razzaque, Mohammed S.

2011-01-01

Heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that helps the molecular maturation of various types of collagens. A close association between increased expression of HSP47 and the excessive accumulation of collagens is found in various human and experimental fibrotic diseases. Increased levels of HSP47 in fibrotic diseases are thought to assist in the increased assembly of procollagen, and thereby contribute to the excessive deposition of collagens in fibrotic areas. Currently, there is not a good universal histological marker to identify collagen-producing cells. Identifying phenotypically altered collagen-producing cells is essential for the development of cell-based therapies to reduce the progression of fibrotic diseases. Since HSP47 has a single substrate, which is collagen, the HSP47 cellular expression provides a novel universal biomarker to identify phenotypically altered collagen-producing cells during wound healing and fibrosis. In this brief article, we explained why HSP47 could be used as a universal marker for identifying phenotypically altered collagen-producing cells

Ductility improvement due to martensite α' decomposition in porous Ti-6Al-4V parts produced by selective laser melting for orthopedic implants.

Science.gov (United States)

Sallica-Leva, E; Caram, R; Jardini, A L; Fogagnolo, J B

2016-02-01

Ti-6Al-4V parts obtained by selective laser melting typically have an acicular α' martensitic microstructure whose ductility is low. Thus, post-heat treatments are useful for increasing ductility. In this work, the effects of sub-β-transus heat treatments on the mechanical properties of Ti-6Al-4V parts with porous structures are correlated with martensite α' phase decomposition. The precipitation of β phase and the gradual transformation of α' into α phase by the diffusion of excess vanadium from α' to β phase are proposed to be the main events of martensite α' phase decomposition in parts fabricated by selective laser melting. The heat treatment performed at 650°C for 1h produced no microstructural changes, but the samples treated for at the same temperature 2h showed a fine precipitation of β phase along the α' needle boundaries. The heat treatment performed at 800°C for 1 or 2h produced a fine α+β microstructure, in which β phase are present as particles fewer in number and larger in size, when compared with the ones present in the sample heat-treated at 650°C for 2h. Heat-treatment of the parts at 800°C for 2h proved to be the best condition, which improved the ductility of the samples while only slightly reducing their strength. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental study on steam gasification of coal using molten blast furnace slag as heat carrier for producing hydrogen-enriched syngas

International Nuclear Information System (INIS)

Duan, Wenjun; Yu, Qingbo; Wu, Tianwei; Yang, Fan; Qin, Qin

2016-01-01

Highlights: • New method for producing HRG by gasification using BFS as heat carrier was proposed. • The continuous experiment of steam gasification in molten BFS was conducted. • The hydrogen-enriched syngas was produced by this method. • The molten BFS waste heat was utilized effectively by steam gasification. • This method could be widely used in steam gasification of different types of coal. - Abstract: The new method for producing hydrogen-enriched syngas (HRG) by steam gasification of coal using molten blast furnace slag (BFS) as heat carrier was established. In order to achieve the HRG production, a gasification system using this method was proposed and constructed. The carbon gasification efficiency (CE), hydrogen yield (YH_2) and cold gasification efficiency (CGE) in the molten slag reactor were measured, and the effects of temperature, S/C (steam to coal) ratio and coal type on the reaction performance were accessed. The results indicated that the preferred temperature was 1350 °C, which ensured the miscibility of coal–steam–slag, the diffusion of reactant in molten BFS as well as recovering waste heat. The optimal S/C ratio was 1.5–2.0 for producing HRG. Under these conditions, the hydrogen fraction was higher than 63% and the gas yield reached to 1.89 Nm"3/kg. The CE and CGE were higher than 96% and 102%, respectively. The YH_2 also reached to 1.20 Nm"3/kg. Meanwhile, different types of coal were successfully gasified in molten BFS reactor for producing HRG. The proposed method enhanced the gasification efficiency of different types of coal, recovered the BFS waste heat effectively, and had important guidance for industrial manufacture.

Economy and development of heating station enterprises managed by forest owners

International Nuclear Information System (INIS)

Tuomi, S.

1998-01-01

Private heating enterprises are a new form of heat generation for municipalities in Finland. In this type the entrepreneur acquires the fuel and takes care of the heating station. The recompense is paid on the basis of the heat amount produced to avoid problems related to i.a. the energy content and the quality of the fuel. The price of heat is typically bound to the price of the light fuel oil. Agreements based on the price development of district heat and chips are also used. In 1997 there were about 50 such enterprises in operation in Finland. The aim of the project is to improve the feasibility of various forms of heating enterprises and to start new heating enterprises. The feasibility is studied both from the viewpoint of the entrepreneur and the municipality. The feasibility is improved by developing production chains of heating enterprises and the operability of heating stations. Establishment of new heating enterprises is promoted by producing and disseminating information to prospective entrepreneurs and municipalities. (orig.) 2 figs., 2 tabs. Bioenergy Research programme

Acoustically enhanced heat transport

Energy Technology Data Exchange (ETDEWEB)

Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)

2016-01-15

We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

Science.gov (United States)

Huang, Song; Chen, Xiao Dong

2013-07-01

The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Improving urban district heating systems and assessing the efficiency of the energy usage therein

Science.gov (United States)

Orlov, M. E.; Sharapov, V. I.

2017-11-01

The report describes issues in connection with improving urban district heating systems from combined heat power plants (CHPs), to propose the ways for improving the reliability and the efficiency of the energy usage (often referred to as “energy efficiency”) in such systems. The main direction of such urban district heating systems improvement suggests transition to combined heating systems that include structural elements of both centralized and decentralized systems. Such systems provide the basic part of thermal power via highly efficient methods for extracting thermal power plants turbines steam, while peak loads are covered by decentralized peak thermal power sources to be mounted at consumers’ locations, with the peak sources being also reserve thermal power sources. The methodology was developed for assessing energy efficiency of the combined district heating systems, implemented as a computer software product capable of comparatively calculating saving on reference fuel for the system.

Techniques for the improvement of heat exchange

International Nuclear Information System (INIS)

Huyghe, J.

1983-01-01

The target of the described techniques is either to improve the performances of the equipements or to reduce their cost price. These techniques were developed at the laboratory scale and some of them were tested in pilot units. Neither of them has yet been applied in commercial plants. Different type of corrogated tubes, thin film evaporation, dropwise condensation, plastic tube or plates, tube configuration and heat pipes are examined [fr

Condensation heat transfer of a feed-water heater and improvement of its performance

International Nuclear Information System (INIS)

Takamori, Kazuhide; Murase, Michio; Baba, Yoshikazu; Aihara, Tsuyoshi

1995-01-01

In this study, a condensation heat transfer model, coupled with a three-dimensional two-phase flow analysis, was developed. In the heat transfer model, the liquid film flow rate on the heat transfer tubes was calculated by a mass balance equation and the liquid film thickness was calculated from the liquid film flow rate using Nusselt's laminar flow model and Fujii's equation for the steam velocity effect. The model was verified by condensation heat transfer experiments. In the experiments, 112 horizontal, staggered tubes with an outer diameter of 16mm and length of 0.55m were used. The calculated over-all heat transfer coefficients agreed with the data within ±5% under the inlet quality conditions of 13-100%. Based on a three-dimensional two-phase flow analysis, an improved feed-water heater with support plates, which have flow holes between the upper and lower tube bundles, was designed. The total heat exchange capacity of the improved feed-water heater increased about 6%. (author)

Evaluating energy, health and carbon co-benefits from improved domestic space heating: A randomised community trial

International Nuclear Information System (INIS)

Preval, Nick; Chapman, Ralph; Pierse, Nevil; Howden-Chapman, Philippa

2010-01-01

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1.

Evaluating energy, health and carbon co-benefits from improved domestic space heating. A randomised community trial

Energy Technology Data Exchange (ETDEWEB)

Preval, Nick; Pierse, Nevil; Howden-Chapman, Philippa [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand); Chapman, Ralph [School of Geography, Graduate Programme in Environmental Studies, Environment and Earth Sciences, Victoria University, PO Box 600, Wellington 6140 (New Zealand)

2010-08-15

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1. (author)

Evaluating energy, health and carbon co-benefits from improved domestic space heating: A randomised community trial

Energy Technology Data Exchange (ETDEWEB)

Preval, Nick [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand); Chapman, Ralph, E-mail: Ralph.chapman@vuw.ac.n [School of Geography, Graduate Programme in Environmental Studies, Environment and Earth Sciences, Victoria University, PO Box 600, Wellington 6140 (New Zealand); Pierse, Nevil; Howden-Chapman, Philippa [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand)

2010-08-15

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1.

Life Cycle Analysis of High Quality Recycled Aggregate Produced byHeating and Rubbing Method

Science.gov (United States)

Shima, Hirokazu; Matsuhashi, Ryuji; Yoshida, Yoshikuni; Tateyashiki, Hisashi

Most of demolished concrete is recycled as road subbase, but its generation is expected to increase rapidly and exceed the demand of road subbase in a near future. To promote the recycling of concrete, the technology to produce high quality recycled aggregate by the heating and rubbing method has been developed. In this method, demolished concrete is heated up to about 300°C in a heater to make cement paste brittle with its dehydration. The heated concrete is then rubbed in two mills to recover the recycled aggregate, while the paste is removed from the surface of aggregate and collected as cement fine powder. In this method, much energy is consumed to heat and rub concrete; however, the cement fine powder is utilized for a soil stabilizer and cement raw materials, so that the environmental load is reduced in cement manufacturing. The life cycle analysis of the recycled aggregate is carried out to evaluate this technology. As a result, the life cycle CO2 is a negative value because the deduction of CO2 emission in cement manufacturing by the powder is much large. This technology is proved to be very effective to reduce CO2.

Heat storage in forest biomass improves energy balance closure

Science.gov (United States)

Lindroth, A.; Mölder, M.; Lagergren, F.

2010-01-01

Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation very well. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance

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

Improvement to the gas cycle energy generating installations with heat recuperation

International Nuclear Information System (INIS)

Tilliette, Zephyr.

1977-01-01

Improvement to the gas cycle energy generating installations with heat recuperation, comprising a heat source, supplying a fluid at high temperature and pressure, an expansion turbine, at least one recuperator fitted to the turbine outlet, a cooler and compressor in series, the compressor returning the high pressure fluid to the source after heat exchange in the recuperator with the low pressure fluid from the turbine. It is characterised in that at least one steam generator is connected to the low pressure end of the recuperator [fr

Thermal-hydraulic analysis of the improved TOPAZ-II power system using a heat pipe radiator

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wenwen; Zhang, Dalin, E-mail: dlzhang@mail.xjtu.edu.cn; Tian, Wenxi; Qiu, Suizheng; Su, G.H.

2016-10-15

Highlights: • The system thermal-hydraulic model of the improved space thermionic reactor is developed. • The temperature reactivity feedback effects of the moderator, UO2 fuel, electrodes and reflector are considered. • The alkali metal heat pipe radiator is modeled with the two dimensional heat pipe model. • The steady state and the start-up procedure of the system are analyzed. - Abstract: A system analysis code coupled with the heat pipe model is developed to analyze the thermal-hydraulic characteristics of the improved TOPAZ-II reactor power system with a heat pipe radiator. The core thermal-hydraulic model, neutron physics model, and the coolant loop component models (including pump, volume accumulator, pipes and plenums) are established. The designed heat pipe radiator, which replaces the original pumped loop radiator, is also modeled, including two-dimensional heat pipe analysis model, fin model and coolant transport duct model. The system analysis code and the heat pipe model is coupled in the transport duct model. Steady state condition and start-up procedure of the improved TOPAZ-II system are calculated. The results show that the designed radiator can satisfy the waste heat rejection requirement of the improved power system. Meanwhile, the code can be used to obtained the thermal characteristics of the system transients such as the start-up process.

Long-Term Heating to Improve Receiver Performance

Energy Technology Data Exchange (ETDEWEB)

Glatzmaier, Greg C.; Cable, Robert; Newmarker, Marc

2017-06-27

The buildup of hydrogen in the heat transfer fluid (HTF) that circulates through components of parabolic trough power plants decreases receiver thermal efficiency, and ultimately, it decreases plant performance and electricity output. The generation and occurrence of hydrogen in the HTF provides the driving force for hydrogen to permeate from the HTF through the absorber tube wall and into the receiver annulus. Getters adsorb hydrogen from the annulus volume until they saturate and are no longer able to maintain low hydrogen pressure. The increase in hydrogen pressure within the annulus significantly degrades thermal performance of the receiver and decreases overall power-plant efficiency. NREL and Acciona Energy North America (Acciona) are developing a method to control the levels of dissolved hydrogen in the circulating HTF. The basic approach is to remove hydrogen from the expansion tanks of the HTF subsystem at a rate that maintains hydrogen in the circulating HTF to a target level. Full-plant steady-state models developed by the National Renewable Energy Laboratory (NREL) predict that if hydrogen is removed from the HTF within the expansion tanks, the HTF that circulates through the collector field remains essentially free of hydrogen until the HTF returns to the power block in the hot headers. One of the key findings of our modeling is the prediction that hydrogen will reverse-permeate out of the receiver annulus if dissolved hydrogen in the HTF is kept sufficiently low. To test this prediction, we performed extended heating of an in-service receiver that initially had high levels of hydrogen in its annulus. The heating was performed using NREL's receiver test stand. Results of our testing showed that receiver heat loss steadily decreased with daily heating, resulting in a corresponding improvement in receiver thermal efficiency.

Heat pump cycle by hydrogen-absorbing alloys to assist high-temperature gas-cooled reactor in producing hydrogen

International Nuclear Information System (INIS)

Satoshi, Fukada; Nobutaka, Hayashi

2010-01-01

A chemical heat pump system using two hydrogen-absorbing alloys is proposed to utilise heat exhausted from a high-temperature source such as a high-temperature gas-cooled reactor (HTGR), more efficiently. The heat pump system is designed to produce H 2 based on the S-I cycle more efficiently. The overall system proposed here consists of HTGR, He gas turbines, chemical heat pumps and reaction vessels corresponding to the three-step decomposition reactions comprised in the S-I process. A fundamental research is experimentally performed on heat generation in a single bed packed with a hydrogen-absorbing alloy that may work at the H 2 production temperature. The hydrogen-absorbing alloy of Zr(V 1-x Fe x ) 2 is selected as a material that has a proper plateau pressure for the heat pump system operated between the input and output temperatures of HTGR and reaction vessels of the S-I cycle. Temperature jump due to heat generated when the alloy absorbs H 2 proves that the alloy-H 2 system can heat up the exhaust gas even at 600 deg. C without any external mechanical force. (authors)

Heat pump having improved defrost system

Science.gov (United States)

Chen, F.C.; Mei, V.C.; Murphy, R.W.

1998-12-08

A heat pump system includes, in an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant: a compressor; an interior heat exchanger; an exterior heat exchanger; an accumulator; and means for heating the accumulator in order to defrost the exterior heat exchanger. 2 figs.

Improving the characteristics of liquid fuel

Energy Technology Data Exchange (ETDEWEB)

Sakan, T

1983-02-04

In order to improve the operational characteristics of a light boiler fuel (LKT) (based on analogous characteristics for a fuel for an internal combustion engine (DVS)) it is proposed to add ether and alcohol to it. The additive of ether improves the viscosity of the fuel, but reduces the heat creating capability. The addition of ether and alcohol (a 3 to 1 ratio by volume) increases the stability of the mixture. With mixing of 75 total percent of the light boiler fuel (a heat creativity of 9,500 kilocalories per liter and a viscosity of 10 centistokes per 30 degrees) with 25 total percent ether produced a fuel with a heat producing capability of 8,690 kilocalories per liter and a viscosity of 2.3 centistokes. With mixing of 70 total percent light boiler oil and 18 total percent ether and 7 total percent alcohol a fuel with a heat creativity of 8,640 kilocalories per liter and a viscosity of 2.7 centistokes was produced.

Improvement of boiling heat transfer by radiation induced boiling enhancement

International Nuclear Information System (INIS)

Imai, Yasuyuki; Okamoto, Koji; Madarame, Haruki; Takamasa, Tomoji

2003-01-01

For nuclear reactor systems, the critical heat flux (CHF) data is very important because it limits reactor efficiency. Improvement of CHF requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. In our previous study, we confirmed that the surface wettability changed significantly or that highly hydrophilic conditions were achieved, after irradiation of 60 Co gamma ray, by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, surface wettability in a high-temperature environment and critical heat flux (CHF) of metal oxides irradiated by gamma rays were investigated. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure. The heating test section made of titanium was 0.2 mm in thickness, 3 mm in height, and 60 mm in length. Oxidation of the surface was carried out by plasma jetting for 40 seconds. The test section was irradiated by 60 Co gamma ray with predetermined radiation intensity and period. The CHF of oxidized titanium was improved up to 100 percent after 800 kGy 60 Co gamma ray irradiation. We call this effect Radiation Induced Boiling Enhancement (RIBE). Before we conducted the CHF experiment, contact angles of the test pieces were measured to show the relationship between wettability and CHF. The CHF in the present experiment increases will surface wettability in the same manner as shown by Liaw and Dhir's results. (author)

Improvement of boiling heat transfer by radiation induced boiling enhancement

International Nuclear Information System (INIS)

Imai, Y.; Okamoto, K.; Madarame, H.; Takamasa, T.

2003-01-01

For nuclear reactor systems, the Critical Heat Flux (CHF) data is very important because it limits reactor efficiency. Improvement of CHF requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. In our previous study, we confirmed that the surface wettability changed significantly or that highly hydrophilic conditions were achieved, after irradiation of 60Co gamma ray, by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, surface wettability in a high-temperature environment and Critical Heat Flux (CHF) of metal oxides irradiated by gamma rays were investigated. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure. The heating test section made of titanium was 0.2mm in thickness, 3mm in height, and 60mm in length. Oxidation of the surfaces was carried out by plasma jetting for 40 seconds. The test section was irradiated by 60Co gamma ray with predetermined radiation intensity and period. The CHF of oxidized titanium was improved up to 100 percent after 800kGy 60Co gamma ray irradiation. We call this effect Radiation Induced Boiling Enhancement (RIBE). Before we conducted the CHF experiment, contact angles of the test pieces were measured to show the relationship between wettability and CHF. The CHF in the present experiment increases with surface wettability in the same manner as shown by Liaw and Dhir's results

An improved mechanistic critical heat flux model for subcooled flow boiling

Energy Technology Data Exchange (ETDEWEB)

Kwon, Young Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-12-31

Based on the bubble coalescence adjacent to the heated wall as a flow structure for CHF condition, Chang and Lee developed a mechanistic critical heat flux (CHF) model for subcooled flow boiling. In this paper, improvements of Chang-Lee model are implemented with more solid theoretical bases for subcooled and low-quality flow boiling in tubes. Nedderman-Shearer`s equations for the skin friction factor and universal velocity profile models are employed. Slip effect of movable bubbly layer is implemented to improve the predictability of low mass flow. Also, mechanistic subcooled flow boiling model is used to predict the flow quality and void fraction. The performance of the present model is verified using the KAIST CHF database of water in uniformly heated tubes. It is found that the present model can give a satisfactory agreement with experimental data within less than 9% RMS error. 9 refs., 5 figs. (Author)

An improved mechanistic critical heat flux model for subcooled flow boiling

Energy Technology Data Exchange (ETDEWEB)

Kwon, Young Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1997-12-31

Based on the bubble coalescence adjacent to the heated wall as a flow structure for CHF condition, Chang and Lee developed a mechanistic critical heat flux (CHF) model for subcooled flow boiling. In this paper, improvements of Chang-Lee model are implemented with more solid theoretical bases for subcooled and low-quality flow boiling in tubes. Nedderman-Shearer`s equations for the skin friction factor and universal velocity profile models are employed. Slip effect of movable bubbly layer is implemented to improve the predictability of low mass flow. Also, mechanistic subcooled flow boiling model is used to predict the flow quality and void fraction. The performance of the present model is verified using the KAIST CHF database of water in uniformly heated tubes. It is found that the present model can give a satisfactory agreement with experimental data within less than 9% RMS error. 9 refs., 5 figs. (Author)

Improvement on control system of the JT-60 radio frequency heating system

Energy Technology Data Exchange (ETDEWEB)

Shinozaki, Shin-ichi; Moriyama, Shinichi; Hiranai, Shinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sato, Fumiaki [Nippon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan)

2003-03-01

On the JT-60 radio frequency (RF) heating system, the decrease in the activity ratio was a problem because of the deterioration of the control system. To improve the reliability, we replaced CAMAC system for a power injection control system, which was a main cause of the trouble, with the microprocessor system. And, a function of computer supported programming function of RF power injection form was introduced, which contributed to reduce a load of operators. Furthermore, personal computers with network communication were introduced to improve a maintenance ability of the control system. As a result, the activity ratio of the RF heating system was improved significantly. (author)

Precooling With Crushed Ice: As Effective as Heat Acclimation at Improving Cycling Time-Trial Performance in the Heat.

Science.gov (United States)

Zimmermann, Matthew; Landers, Grant; Wallman, Karen; Kent, Georgina

2018-02-01

This study compared the effects of precooling (ice ingestion) and heat-acclimation training on cycling time-trial (CTT) performance in the heat. Fifteen male cyclists/triathletes completed two 800-kJ CTTs in the heat, with a 12-d training program in between. Initially, all participants consumed 7 g/kg of water (22°C) in 30 min before completing an 800-kJ CTT in hot, humid conditions (pre-CTT) (35°C, 50% relative humidity [RH]). Participants were then split into 2 groups, with the precooling group (n = 7) training in thermoneutral conditions and then undergoing precooling with ice ingestion (7 g/kg, 1°C) prior to the final CTT (post-CTT) and the heat-acclimation group (n = 8) training in hot conditions (35°C, 50% RH) and consuming water (7 g/kg) prior to post-CTT. After training in both conditions, improvement in CTT time was deemed a likely positive benefit (precooling -166 ± 133 s, heat acclimation -105 ± 62 s), with this result being similar between conditions (d = 0.22, -0.68-1.08 90% confidence interval [CI]). Core temperature for post-CTT was lower in precooling than in heat acclimation from 20 min into the precooling period until the 100-kJ mark of the CTT (d > 0.98). Sweat onset occurred later in precooling (250 ± 100 s) than in heat acclimation (180 ± 80 s) for post-CTT (d = 0.65, -0.30-1.50 90% CI). Thermal sensation was lower at the end of the precooling period prior to post-CTT for the precooling trial than with heat acclimation (d = 1.24, 0.90-1.58 90% CI). Precooling with ice ingestion offers an alternative method of improving endurance-cycling performance in hot conditions if heat acclimation cannot be attained.

Effect of heat treatment on carbon steel pipe welds

International Nuclear Information System (INIS)

Mohamad Harun.

1987-01-01

The heat treatment to improve the altered properties of carbon steel pipe welds is described. Pipe critical components in oil, gasification and nuclear reactor plants require adequate room temperature toughness and high strength at both room and moderately elevated temperatures. Microstructure and microhardness across the welds were changed markedly by the welding process and heat treatment. The presentation of hardness fluctuation in the welds can produce premature failure. A number of heat treatments are suggested to improve the properties of the welds. (author) 8 figs., 5 refs

Performance improvement in a tubular heat exchanger by punched delta-winglet vortex generators

Science.gov (United States)

Khanoknaiyakarn, C.; Promvonge, P.; Thianpong, C.; Skullong, S.

2018-01-01

A novel tubular heat exchanger incorporated with punched delta-winglet vortex generators (called perforated delta-winglet vortex generator, P-DWVG) is proposed for improving its thermal performance and energy saving. The P-DWVG elements are punched out from a straight tape having its width nearly equal to the tube diameter before insertion. The main aim at employing the P-DWVG insert is to produce counter-rotating vortices along the tube to promote turbulence intensity inside as well as to transport the cold fluid at the central core to the near-wall regions. The experiment was performed to study thermal behaviors in a uniform heat-fluxed tube inserted with P-DWVGs. The P-DWVGs with the attack angle of 45° were mounted periodically with three different blockage ratios (BR = 0.1, 0.2 and 0.3) and two pitch ratios (PR = 2 and 3). Air as the test fluid was varied to obtain turbulent airflow for Reynolds number (Re) in a range of 4,150-25,500. The experimental results show that the P-DWVG provides a considerable increase in the rate of heat transfer around 3.1-4.01 times whereas friction factor increases around 11.44- 34.23 times higher than the plain tube. To assess the real benefits of P-DWVGs, thermal performance factor (TEF) is examined and in the range of 1.39-1.48 where its maximum is at BR = 0.1 and PR = 2.

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

Experimental and CFD simulation of heat efficiency improvement in geothermal spas

International Nuclear Information System (INIS)

Jalilinasrabady, Saeid; Palsson, Halldor; Saevarsdottir, Gudrun; Itoi, Ryuichi; Valdimarsson, Pall

2013-01-01

Hot spas and jacuzzis are popular in Iceland due to the abundance of reasonably prized geothermal heat available. However the water from the DH (district heating) system is too warm to be admitted directly into the spa. For safety reasons the water is mixed with cold water, from 75 °C down to 50 °C, which leads to wasting a large quantity of heat. Therefore a design was suggested that enables the feeding of geothermal water directly into the pot, omitting the step of mixing it with cold water. The idea is to employ an open heat exchanger that transfers much heat from the geothermal water to the bulk water in the spa, before letting it mix with the spa water. A case study was done for one particular spa. Heat load was calculated and measured when the spa was in use, and when it was unused. A design is suggested employing a circular double-plate which is to be placed at bottom of pot. This unit will function as an open heat exchanger feeding DH water into the pot. Free convection takes place at the up side of the upper plate and forced convection below the upper plate. Heat-transfer coefficient for both was calculated. Temperature field in the pool before and after implementation of the open heat exchanger was measured at different points using thermocouples. The measured temperatures were compared to thermal and fluid-dynamic simulation of the temperature and flow fields obtaining good accordance. Results are reasonable and promising for a good design that may considerably reduce the energy expenses for a continuously heated geothermal spa. More detailed measurements were made on the upper plate of the heat exchanger and detailed simulation of the heat exchanger itself was then used to obtain a value for the heat-transfer coefficient for the upper plate to the surrounding water. This information was used to make an improved design for the open plate heat exchanger, stating that a diameter of 63 cm and a thickness of 1.5 cm were suggested as final design. Due to

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

KAUST Repository

Li, Kuang-Hui; Alotaibi, Hamad S.; Sun, Haiding; Lin, Ronghui; Guo, Wenzhe; Torres-Castanedo, Carlos G.; Liu, Kaikai; Galan, Sergio V.; Li, Xiaohang

2018-01-01

In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

KAUST Repository

Li, Kuang-Hui

2018-02-23

In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

Using containment analysis to improve component cooling water heat exchanger limits

International Nuclear Information System (INIS)

Da Silva, H.C.; Tajbakhsh, A.

1995-01-01

The Comanche Peak Steam Electric Station design requires that exit temperatures from the Component Cooling Water Heat Exchanger remain below 330.37 K during the Emergency Core Cooling System recirculation stage, following a hypothetical Loss of Coolant Accident (LOCA). Due to measurements indicating a higher than expected combination of: (a) high fouling factor in the Component Cooling Water Heat Exchanger with (b) high ultimate heat sink temperatures, that might lead to temperatures in excess of the 330.37 K limit, if a LOCA were to occur, TUElectric adjusted key flow rates in the Component Cooling Water network. This solution could only be implemented with improvements to the containment analysis methodology of record. The new method builds upon the CONTEMPT-LT/028 code by: (a) coupling the long term post-LOCA thermohydraulics with a more detailed analytical model for the complex Component Cooling Water Heat Exchanger network and (b) changing the way mass and energy releases are calculated after core reflood and steam generator energy is dumped to the containment. In addition, a simple code to calculate normal cooldowns was developed to confirm RHR design bases were met with the improved limits

Heat pipe heat exchangers in heat recovery systems

Energy Technology Data Exchange (ETDEWEB)

Stulc, P; Vasiliev, L L; Kiseljev, V G; Matvejev, Ju N

1985-01-01

The results of combined research and development activities of the National Research Institute for Machine Design, Prague, C.S.S.R. and the Institute for Heat and Mass Transfer, Minsk, U.S.S.R. concerning intensification heat pipes used in heat pipe heat exchangers are presented. This sort of research has been occasioned by increased interest in heat power economy trying to utilise waste heat produced by various technological processes. The developed heat pipes are deployed in construction of air-air, gas-air or gas-gas heat recovery exchangers in the field of air-engineering and air-conditioning. (author).

Industrial furnace with improved heat transfer

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1992-07-07

This patent describes an industrial furnace for heating work which emits volatiles during heating. It comprises a generally cylindrical, closed end furnace section defining a sealable heat transfer chamber for heating work disposed therein; fan means for directing furnace atmosphere as a swirling wind mass about the interior of the furnace section over a portion thereof; heat means for heating the wind mass within the fan chamber; and an incineration track formed as a circumferentially extending groove about the exterior of the furnace section and in heat transfer relationship with and situated at least to extend about a portion of the fan chamber.

District heating

International Nuclear Information System (INIS)

Hansen, L.

1993-01-01

The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

Umbilical Cord Blood-Derived Stem Cells Improve Heat Tolerance and Hypothalamic Damage in Heat Stressed Mice

Directory of Open Access Journals (Sweden)

Ling-Shu Tseng

2014-01-01

Full Text Available Heatstroke is characterized by excessive hyperthermia associated with systemic inflammatory responses, which leads to multiple organ failure, in which brain disorders predominate. This definition can be almost fulfilled by a mouse model of heatstroke used in the present study. Unanesthetized mice were exposed to whole body heating (41.2°C for 1 hour and then returned to room temperature (26°C for recovery. Immediately after termination of whole body heating, heated mice displayed excessive hyperthermia (body core temperature ~42.5°C. Four hours after termination of heat stress, heated mice displayed (i systemic inflammation; (ii ischemic, hypoxic, and oxidative damage to the hypothalamus; (iii hypothalamo-pituitary-adrenocortical axis impairment (reflected by plasma levels of both adrenocorticotrophic-hormone and corticosterone; (iv decreased fractional survival; and (v thermoregulatory deficits (e.g., they became hypothermia when they were exposed to room temperature. These heatstroke reactions can be significantly attenuated by human umbilical cord blood-derived CD34+ cells therapy. Our data suggest that human umbilical cord blood-derived stem cells therapy may improve outcomes of heatstroke in mice by reducing systemic inflammation as well as hypothalamo-pituitary-adrenocortical axis impairment.

Improved confinement with ion cyclotron hydrogen minority heating on Tore Supra

International Nuclear Information System (INIS)

Hoang, G.T.; Monier-Garbet, P.; Aniel, T.; Bourdelle, C.; Eriksson, L.G.; Garbet, X.; Grisolia, C.; Platz, P.; Budny, R.V.

1999-02-01

Tore Supra experiments are presently devoted to study the high density and high radiation regimes with radio frequency heating. Recent results of ion cyclotron minority heating have been obtained with an improved L-mode confinement, close to ELMy H-mode, at relatively high density (up to 80% of Greenwald limit). Such a regime is very promising as possible scenario in a next step tokamak. (authors)

Evidence of an Unidentified Extracellular Heat-Stable Factor Produced by Lysobacter enzymogenes (OH11) that Degrade Fusarium graminearum PH1 Hyphae.

Science.gov (United States)

Odhiambo, Benard Omondi; Xu, Gaoge; Qian, Guoliang; Liu, Fengquan

2017-04-01

Lysobacter enzymogenes OH11 produces heat-stable antifungal factor (HSAF) and lytic enzymes possessing antifungal activity. This study bio-prospected for other potential antifungal factors besides those above. The cells and extracellular metabolites of L. enzymogenes OH11 and the mutants ΔchiA, ΔchiB, ΔchiC, Δclp, Δpks, and ΔpilA were examined for antifungal activity against Fusarium graminearum PH1, the causal agent of Fusarium head blight (FHB). Results evidenced that OH11 produces an unidentified extracellular heat-stable degrading metabolite (HSDM) that exhibit degrading activity on F. graminearum PH1 chitinous hyphae. Interestingly, both heat-treated and non-heat-treated extracellular metabolites of OH11 mutants exhibited hyphae-degrading activity against F. graminearum PH1. Enzyme activity detection of heat-treated metabolites ruled out the possibility of enzyme degradation activity. Remarkably, the PKS-NRPS-deficient mutant Δpks cannot produce HSAF or analogues, yet its metabolites exhibited hyphae-degrading activity. HPLC analysis confirmed no HSAF production by Δpks. Δclp lacks hyphae-degrading ability. Therefore, clp regulates HSDM and extracellular lytic enzymes production in L. enzymogenes OH11. ΔpilA had impaired surface cell motility and significantly reduced antagonistic properties. ΔchiA, ΔchiB, and ΔchiC retained hyphae-degrading ability, despite having reduced abilities to produce chitinase enzymes. Ultimately, L. enzymogenes OH11 can produce other unidentified HSDM independent of the PKS-NRPS genes. This suggests HSAF and lytic enzymes production are a fraction of the antifungal mechanisms in OH11. Characterization of HSDM, determination of its biosynthetic gene cluster and understanding its mode of action will provide new leads in the search for effective drugs for FHB management.

Open heat exchanger for improved heat efficiency in geothermal spas

Energy Technology Data Exchange (ETDEWEB)

Nasrabady, S.J.; Palsson, H.; Saevarsdottir, G.A.

2008-09-15

Hot spas and Jacuzzis are popular in Iceland due to the abundance of reasonably prized geothermal heat available. However the water from the district heating system is too warm to be admitted directly into the spa. For safety reasons the water is mixed with cold water, in order to reduce temperature from about 80 deg C down to 45 deg C, which leads to wasting a large quantity of heat. Therefore a design is suggested here that enables the feeding of geothermal water directly into the spa, omitting the step of mixing it with cold water. The idea is to employ an open heat exchanger that transfers heat from the geothermal water to the bulk water in the spa, before letting it mix with the spa water. A case study was done for one particular spa. Heat load was calculated and measured when the spa was in use, and when it was unused. A design is suggested employing a circular double-plate which is to be placed at the bottom of the spa. This unit will function as an open heat exchanger feeding district heating water into the spa. Free convection takes place at the upper side of the upper plate and forced convection below the upper plate. Heat transfer coefficient for both was calculated. Using results from calculations, temperature distribution at critical parts of spa and plate was modeled. Results are reasonable and promising for a good design that may considerably reduce the energy expenses for a continuously heated geothermal spa

Geothermal electricity generation and desalination: an integrated process design to conserve latent heat with operational improvements

KAUST Repository

Missimer, Thomas M.; Ng, Kim Choon; Thuw, Kyaw; Wakil Shahzad, Muhammad

2016-01-01

A new process combination is proposed to link geothermal electricity generation with desalination. The concept involves maximizing the utilization of harvested latent heat by passing the turbine exhaust steam into a multiple effect distillation system and then into an adsorption desalination system. Processes are fully integrated to produce electricity, desalted water for consumer consumption, and make-up water for the geothermal extraction system. Further improvements in operational efficiency are achieved by adding a seawater reverse osmosis system to the site to utilize some of the generated electricity and using on-site aquifer storage and recovery to maximize water production with tailoring of seasonal capacity requirements and to meet facility maintenance requirements. The concept proposed conserves geothermally harvested latent heat and maximizes the economics of geothermal energy development. Development of a fully renewable energy electric generation-desalination-aquifer storage campus is introduced within the framework of geothermal energy development. © 2016 The Author(s). Published by Taylor & Francis

Geothermal electricity generation and desalination: an integrated process design to conserve latent heat with operational improvements

KAUST Repository

Missimer, Thomas M.

2016-02-05

A new process combination is proposed to link geothermal electricity generation with desalination. The concept involves maximizing the utilization of harvested latent heat by passing the turbine exhaust steam into a multiple effect distillation system and then into an adsorption desalination system. Processes are fully integrated to produce electricity, desalted water for consumer consumption, and make-up water for the geothermal extraction system. Further improvements in operational efficiency are achieved by adding a seawater reverse osmosis system to the site to utilize some of the generated electricity and using on-site aquifer storage and recovery to maximize water production with tailoring of seasonal capacity requirements and to meet facility maintenance requirements. The concept proposed conserves geothermally harvested latent heat and maximizes the economics of geothermal energy development. Development of a fully renewable energy electric generation-desalination-aquifer storage campus is introduced within the framework of geothermal energy development. © 2016 The Author(s). Published by Taylor & Francis

Improvement of stress-rupture life of GTD-111 by second solution heat treatment

International Nuclear Information System (INIS)

Yang, Caixiong; Xu, Yulai; Zhang, Zixing; Nie, Heng; Xiao, Xueshan; Jia, Guoqing; Shen, Zhi

2013-01-01

Highlights: ► The second solution heat treatment promoted the solution of γ–γ′ eutectic into γ matrix. ► The volume fraction of γ′ increases significantly after adding the second solution heat treatment. ► The improved stress-rupture life is primarily due to the increased volume fraction of γ′ phase. -- Abstract: An added second solution heat treatment was conducted to investigate its effects on the microstructures and stress-rupture properties of GTD-111. The microstructures were analyzed by scanning electron microscope after each step of heat treatments. The stress-rupture life of GTD-111 dramatically increases from about 180 to 288 h at 871 °C/310 MPa after adding a second solution heat treatment. The added second solution heat treatment promoted the solution of γ–γ′ eutectic into γ matrix, and facilitated the nucleation and precipitate of the secondary γ′ particles. The distribution of γ′ phase becomes much denser, the width of γ matrix channel is also reduced, and the volume fraction of γ′ phase significantly increases from about 29.3% to 44.2%. The improved stress-rupture life is primarily due to the increased volume fraction of γ′ phase. The carbides mainly consist of MC and a small amount of M 23 C 6 , which may prevent the dislocation moving and/or grain boundary sliding, and further improve the stress-rupture properties of GTD-111.

The combustion heat of power producing shale based on individual deliveries for the years 1968 to 1981

Energy Technology Data Exchange (ETDEWEB)

Yyspuu, L M; Rayur, K W; Sits, Kh I

1983-01-01

The results are cited of a retrospective study of the specific combustion heat of power producing shale relative to the geological and mining technological conditions for nine mines and four open pits of the Baltic Sea Basin. In 1981 the maximal mean annual combustion heatQsigma-c of 12.44 megajoules per kilogram was held by the shales from the Tammiku mine, while the minimum of 10.12 megajoules per kilogram was held by the shales from the Leningradskaya mine. The results are used in a predictive evaluation of the heat creativity of the total fuel of the Baltic Sea region and the Estonian state regional electric power plants (GRES) for the coming years.

Recouping the thermal-to-electric conversion loss by the use of waste heat

International Nuclear Information System (INIS)

Bradley, W.J.

1976-01-01

This paper looks at ways to recoup the thermal-to-electric conversion loss of our thermal power generating stations. These stations now produce twice as much low-grade waste heat as they do electricity. We can improve the situation in two ways: by improving the station efficiency, and by utilizing the low-grade heat beneficially. The following options are examined: N 2 O 4 turbines condensing at 10 deg C; power from moderator waste heat; 50 MW heat pump for district heating; industrial parks with integrated waste heat upgrading station. (author)

Feasibility improvement project of a district heat supply system in Dalian, China

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Investigations and discussions have been given on energy saving possibilities at two medium-sized heat and power supplying plants in the city of Dalian in China. The project will improve the operation methods of the heat and power plants so that the energy cost can be minimized, and attempt to improve the boiler heat efficiency and save the energy by means of heat recovery and utilization. The draft modification plan for energy conservation has planned operation optimization for energy conservation, control of boiler operation under variable pressure, modification of the external boiler heat converter, use of inverters for the large capacity motors for boilers, and recovery of heat from the boiler blow-down water. In the analysis, models were structured from the operation data, and the effects of applying the energy saving measures were derived from simulation. As a result, the energy saving effect was found to be about 13,000 tons at the Chunhai plant and about 7,000 tons at the Pulandian plant annually (converted to oil). The reduction in greenhouse gas emission was found to be about 40,000 tons at the Chunhai plant and about 20,000 tons at the Pulandian plant annually. The number of years for investment payback is about 4.1 years at the Chunhai plant, and about 4.9 years at the Pulandian plant, wherein good profitability can be estimated. (NEDO)

Residual heat use generated by a 12 kW fuel cell in an electric vehicle heating system

International Nuclear Information System (INIS)

Colmenar-Santos, Antonio; Alberdi-Jiménez, Lucía; Nasarre-Cortés, Lorenzo; Mora-Larramona, Joaquín

2014-01-01

A diesel or gasoline vehicle heating is produced by the heat of the engine coolant liquid. Nevertheless, electric vehicles, due to the fact that electric motor transform directly electricity into mechanical energy through electromagnetic interactions, do not generate this heat so other method of providing it has to be developed. This study introduces the system developed in a fuel cell electric vehicle (lithium-ion battery – fuel cell) with residual heat use. The fuel cell electric vehicle is driven by a 12 kW PEM (proton exchange membrane) fuel cell. This fuel cell has an operating temperature around 50 °C. The residual heat generated was originally wasted by interaction with the environment. The new developed heating system designed integrates the heat generated by the fuel cell into the heating system of the vehicle, reducing the global energy consumption and improving the global efficiency as well. - Highlights: • Modification of heating system was done by introducing the residual heat from fuel cell. • Maximum heat achieved by the heating radiator of 9.27 kW. • Reduction of the heat dissipation by the fuel cell cooling system 1.5 kW. • Total efficiency improvement of 20% with an autonomy increase of 21 km

Role of heat tint on pitting corrosion of 304 austenitic stainless steel in chloride environment

Energy Technology Data Exchange (ETDEWEB)

Elshawesh, F.; Elhoud, A. [Petroleum Research Center, P. O. Box 6431, Tripoli (Libyan Arab Jamahiriya)

2004-07-01

The effect of simulated heat tint produced by air oxidation at a wide range of temperatures 200, 400, 600, 800 and 1050 deg. C on pitting potential of 304 austenitic stainless steel was studied in environment of different chloride concentration. It was found that the heat tint effect depends on the heating temperature. The most effective heat tint was that produced at the high temperature up to 1050 deg. C and hence less pitting potential and low corrosion resistance. In order to improve the surface pitting corrosion resistance, acid pickling of hydrochloric acid was applied at different time and temperatures of 15 and 60 min, room temperature and 60 deg. C, respectively. Improvement in pitting potential was achieved as the pickling time and temperature increase. This is can be attributed to the removal of depleted chromium oxide film produced during the heat tint. (authors)

Equipment for heating the exhaust gases of internal combustion engines in order to improve afterburning

Energy Technology Data Exchange (ETDEWEB)

Masaki,

1976-04-15

The device described here serves to heat exhaust gases of internal combustion engines by heat exchange with hot gases and also, in cold engines, to raise the temperature of the fuel-air mixture drawn in by the engine. The device is installed next to the outlet opening of the engine. It consists of a burner to generate the hot gas, as well as a heat exchanger permitting heat supply to the exhaust gases and a hot-gas line leading to the intake line. Heating of the air is taken in leads to a better atomization of the mixture and thus to improved combustion. Heating of the exhaust gases improves afterburning. The burner generating the hot gas is shut off when the normal operational temperature of the engine is reached. The temperature is controlled by means of a temperature sensor installed in the device.

Thermoelectric as recovery and harvesting of waste heat from portable generator

Science.gov (United States)

Mustafa, S. N.; Kamarrudin, N. S.; Hashim, M. S. M.; Bakar, S. A.; Razlan, Z. M.; Harun, A.; Ibrahim, I.; Faizi, M. K.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

Generation of waste heat was ineluctable especially during energy producing process. Waste heat falls into low temperature grade make it complicated to utilize. Thermoelectric generator (TEG) offers opportunity to harvest any temperature grade heat into useful electricity. This project is covered about recovery and utilizing waste heat from portable electric generator by using a TEG which placed at exhaust surface. Temperature difference at both surfaces of TEG was enhanced with supplying cold air from a wind blower. It is found that, even at low air speed, the TEG was successfully produced electricity with aid from DC-DC booster. Results shows possibility to harvest low temperature grade heat and still exist areas for continual improvement.

Basic investigation on promotion of joint implementation in fiscal 2000. Investigations on modification and improvement project for Potoshani district heating and heat supplying facilities in Romania; 2000 nendo kyodo jisshi nado suishin kiso chosa hokokusho. Romania koku Potoshani chiiki danbo netsukyokyu setsubi no kaishu oyobi kaizen keikaku chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Discussions have been given on the improvement and modification project intended of saving energies and reducing greenhouse gas emission in the Potoshani district heating and heat supplying facilities in Romania. Thirty years have elapsed since the building of the Potoshani district heating and heat supplying facilities, whereas noticeable energy loss has occurred due to aged deterioration, such as thermal efficiency decrease, performance decrease, and hot water leakage due to piping corrosion. The present project is intended to improve the heat production and power generation facility efficiencies, and reduce the heat loss in heat transportation and distribution to less than 5%. The improvements will be implemented by replacing and rehabilitating the existing boilers, replacing the turbine generators, and replacing the transportation and distribution pipelines and heat exchangers. As a result of the discussions, the present project is estimated to result in annual fuel conservation of 35,820 tons of crude oil equivalent, and annual reduction of the greenhouse gas emission of 110,835 t-CO2. The total amount of the initial investment for the project would be 11.369 billion yen, and the payback period would be 12 years. The project will produce profit of 31.358 billion yen in 20 years, thus the project is financially feasible. (NEDO)

An application of data mining in district heating substations for improving energy performance

Science.gov (United States)

Xue, Puning; Zhou, Zhigang; Chen, Xin; Liu, Jing

2017-11-01

Automatic meter reading system is capable of collecting and storing a huge number of district heating (DH) data. However, the data obtained are rarely fully utilized. Data mining is a promising technology to discover potential interesting knowledge from vast data. This paper applies data mining methods to analyse the massive data for improving energy performance of DH substation. The technical approach contains three steps: data selection, cluster analysis and association rule mining (ARM). Two-heating-season data of a substation are used for case study. Cluster analysis identifies six distinct heating patterns based on the primary heat of the substation. ARM reveals that secondary pressure difference and secondary flow rate have a strong correlation. Using the discovered rules, a fault occurring in remote flow meter installed at secondary network is detected accurately. The application demonstrates that data mining techniques can effectively extrapolate potential useful knowledge to better understand substation operation strategies and improve substation energy performance.

Mixture for producing fracture-resistant, fiber-reinforced ceramic material by microwave heating

Science.gov (United States)

Meek, T.T.; Blake, R.D.

1985-04-03

A fracture-resistant, fiber-reinforced ceramic substrate is produced by a method which involves preparing a ceramic precursor mixture comprising glass material, a coupling agent, and resilient fibers, and then exposing the mixture to microwave energy. The microwave field orients the fibers in the resulting ceramic material in a desired pattern wherein heat later generated in or on the substrate can be dissipated in a desired geometric pattern parallel to the fiber pattern. Additionally, the shunt capacitance of the fracture-resistant, fiber-reinforced ceramic substrate is lower which provides for a quicker transit time for electronic pulses in any conducting pathway etched into the ceramic substrate.

Process for producing volatile hydrocarbons from hydrocarbonaceous solids

Energy Technology Data Exchange (ETDEWEB)

1949-02-03

In a process for producing volatile hydrocarbons from hydrocarbonaceous solids, a hydrocarbonaceus solid is passed in subdivided state and in the form of a bed downwardly through an externally unheated distilling retort wherein the evolution of volatiles from the bed is effected while solid material comprising combustible heavy residue is discharged from the lower portion of the bed and retort, combustibles are burned from the discharged solid material. The admixture resultant combustion gases with the vapours evolved in the retort is prevented, and a stream of hydrocarbon fluid is heated by indirect heat exchange with hot combustion gases produced by burning to a high temperature and is introduced into the distilling retort and direct contact with bed, supplying heat to the latter for effecting the evolution of volatiles from the hydrocarbonaceous solid. The improvement consists of subjecting the volatile distillation products evolved and removed from the bed to a fractionation and separating selected relatively light and heavy hydrocarbon fractions from the distillation products, withdrawing at least one of the selected fractions from the prcess as a product heating at least one other of the selected fractions to high temperature by the indirect heat exchange with hot combustion gases, and introducing the thus heated hydrocarbon fraction into direct contact with the bed.

A new methodology for greenhouse gas reduction in industry through improved heat exchanging and/or integration of combined heat and power

International Nuclear Information System (INIS)

Axelsson, H.; Asblad, A.; Berntsson, T.

1999-01-01

This paper presents a method that identifies economically optimal combinations of enhanced heat recovery, integration of combined heat and power (CHP), and fuel switching, in an existing industrial energy system at various emission levels. Novel types of composite curves based on pinch technology, representing the existing temperature levels for supplying heat and the possible ones that may be attained after retrofitting, are used as tools for estimating the opportunities for CHP and the trade-off between improved heat exchanging and CHP. The method is explained by an example. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Heat transmission systems for heating and potable water. New requirements and problem solutions for hygiene, safety and improved heat utilization. Waermeuebertragungssysteme fuer Heizung und Trinkwasser. Neue Anforderungen und Problemloesungen bezueglich Hygiene, Sicherheit und besserer Waermenutzung

Energy Technology Data Exchange (ETDEWEB)

Kremer, R

1989-10-01

In the past, additional demands were made on heat transmission systems regarding hygienic requirements in potable water heating plant for hospitals, hotels, sanatoriums and old-age homes, safety requirements to protect the potable water from the penetration of hazardous substances and requirements for improved heat utilization through return flow cooling and condensate cooling in the district heating. Where potable water heaters are concerned, safety radiators for heat transfer which comply with the requirements of DIN 1988 Part 2 and Part 4, as well as water heaters with permanent disinfection which are legionnaires' disease-proof, are now available for use in hospitals, old age homes and sanatoriums. For the district heating sector, improved range systems with low concentration in the hot water sector as well as condensate heat utilizing systems have been further developed in the steam heating sector. (orig.).

An improved model of heat-induced hyperalgesia--repetitive phasic heat pain causing primary hyperalgesia to heat and secondary hyperalgesia to pinprick and light touch.

Science.gov (United States)

Jürgens, Tim P; Sawatzki, Alexander; Henrich, Florian; Magerl, Walter; May, Arne

2014-01-01

This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (-31%) and in particular of secondary hyperalgesia (-59%) as well as the magnitude of hyperalgesia (-59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input.

An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

Science.gov (United States)

Henrich, Florian; Magerl, Walter; May, Arne

2014-01-01

This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

Analysis of Functional Constituents in Mulberry (Morus alba L.) Twigs by Different Cultivars, Producing Areas, and Heat Processings

Science.gov (United States)

Choi, Sang Won; Jang, Yeon Jeong; Lee, Yu Jin; Leem, Hyun Hee; Kim, Eun Ok

2013-01-01

Four functional constituents, oxyresveratrol 3′-O-β-D-glucoside (ORTG), oxyresveratrol (ORT), t-resveratrol (RT), and moracin (MC) were isolated from the ethanolic extract of mulberry (Morus alba L.) twigs by a series of isolation procedures, including solvent fractionation, and silica-gel, ODS-A, and Sephadex LH-20 column chromatographies. Their chemical structures were identified by NMR and FABMS spectral analysis. Quantitative changes of four phytochemicals in mulberry twigs were determined by HPLC according to cultivar, producing area, and heat processing. ORTG was a major abundant compound in the mulberry twigs, and its levels ranged from 23.7 to 105.5 mg% in six different mulberry cultivars. Three other compounds were present in trace amounts (<1 mg/100 g) or were not detected. Among mulberry cultivars examined, “Yongcheon” showed the highest level of ORTG, whereas “Somok” had the least ORTG content. Levels of four phytochemicals in the mulberry twigs harvested in early September were higher than those harvested in early July. Levels of ORTG and ORT in the “Cheongil” mulberry twigs produced in the Uljin area were higher than those produced in other areas. Generally, levels of ORTG and ORT in mulberry twigs decreased with heat processing, such as steaming, and microwaving except roasting, whereas those of RT and MC did not considerably vary according to heat processing. These results suggest that the roasted mulberry twigs may be useful as potential sources of functional ingredients and foods. PMID:24551827

Development of technique to apply induction heating stress improvement to recirculation inlet nozzle

International Nuclear Information System (INIS)

Chiba, Kunihiko; Nihei, Kenichi; Ootaka, Minoru

2009-01-01

Stress corrosion cracking (SCC) have been found in the primary loop recirculation (PLR) systems of boiling water reactors (BWR). Residual stress in welding heat-affected zone is one of the factors of SCC, and the residual stress improvement is one of the most effective methods to prevent SCC. Induction heating stress improvement (IHSI) is one of the techniques to improve reduce residual stress. However, it is difficult to apply IHSI to the place such as the recirculation inlet nozzle where the flow stagnates. In this present study, the technique to apply IHSI to the recirculation inlet nozzle was developed using water jet which blowed into the crevice between the nozzle safe end and the thermal sleeve. (author)

Developing a strategy for improving efficiency in the heating sector in central and eastern Europe

Energy Technology Data Exchange (ETDEWEB)

Meyer, A.S. [World Bank, Washington, DC (United States)

1995-12-31

Heating is a vital energy service in Central and Eastern Europe, but the current delivery mechanisms are riddled with problems. District heating (DH) in its present technical form and with the present management structures is an inefficient system which produces expensive heat. Customers cannot control it and react to overheating by opening windows, even in winter. DH facilities together with other forms of individual heating are responsible for air pollution, causing severe impacts on the health of urban residents. The issues relating to DH are discussed, the first World Bank activities and experiences with projects in Poland are analyzed, and the cornerstones of a strategy to support future World Bank financing and the development of sound heating policies in CEE are presented.

Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans.

Science.gov (United States)

Brunt, Vienna E; Howard, Matthew J; Francisco, Michael A; Ely, Brett R; Minson, Christopher T

2016-09-15

A recent 30 year prospective study showed that lifelong sauna use reduces cardiovascular-related and all-cause mortality; however, the specific cardiovascular adaptations that cause this chronic protection are currently unknown. We investigated the effects of 8 weeks of repeated hot water immersion ('heat therapy') on various biomarkers of cardiovascular health in young, sedentary humans. We showed that, relative to a sham group which participated in thermoneutral water immersion, heat therapy increased flow-mediated dilatation, reduced arterial stiffness, reduced mean arterial and diastolic blood pressure, and reduced carotid intima media thickness, with changes all on par or greater than what is typically observed in sedentary subjects with exercise training. Our results show for the first time that heat therapy has widespread and robust effects on vascular function, and as such, could be a viable treatment option for improving cardiovascular health in a variety of patient populations, particularly those with limited exercise tolerance and/or capabilities. The majority of cardiovascular diseases are characterized by disorders of the arteries, predominantly caused by endothelial dysfunction and arterial stiffening. Intermittent hot water immersion ('heat therapy') results in elevations in core temperature and changes in cardiovascular haemodynamics, such as cardiac output and vascular shear stress, that are similar to exercise, and thus may provide an alternative means of improving health which could be utilized by patients with low exercise tolerance and/or capabilities. We sought to comprehensively assess the effects of 8 weeks of heat therapy on biomarkers of vascular function in young, sedentary subjects. Twenty young, sedentary subjects were assigned to participate in 8 weeks (4-5 times per week) of heat therapy (n = 10; immersion in a 40.5°C bath sufficient to maintain rectal temperature ≥ 38.5°C for 60 min per session) or thermoneutral water

Advanced radioisotope heat source for Stirling Engines

International Nuclear Information System (INIS)

Dobry, T.J.; Walberg, G.

2001-01-01

The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions

Utilization of a maltotetraose-producing amylase as a whole wheat bread improver: dough rheology and baking performance.

Science.gov (United States)

Bae, Woosung; Lee, Sung Ho; Yoo, Sang-Ho; Lee, Suyong

2014-08-01

A maltotetraose-producing enzyme (G4-amylase) was utilized to improve the baking performance of whole-grain wheat flour. Whole-grain bread dough prepared with G4-amylase showed reduced water absorption and increased development time, while the dough stability was not affected. Also, the G4-amylase-treated samples exhibited lower Mixolab torque values than the control upon heating and cooling. Rheological measurements showed the decreased ratio of Rmax /E and increased tan δ, clearly demonstrating that the viscous characteristics of whole-grain bread dough became dominant with increasing levels of G4-amylase. The use of G4-amylase produced whole-grain wheat breads with a variety of maltooligosaccharides, primarily maltotetraose that positively contributed to the bread volume (1.2-fold higher than the control). Moreover, G4-amylase delayed the crumb firming of whole-grain wheat bread during a 7-d storage period, showing that it can function as an antiretrogradation agent to enhance the quality attributes of whole-grain wheat bread. © 2014 Institute of Food Technologists®

Improvement of the CFC structure to withstand high heat flux

International Nuclear Information System (INIS)

Pestchanyi, S.; Landman, I.

2006-01-01

Analysis of the peculiarities of the erosion of NB31 CFC allowed proposition of a new CFC fibre structure for considerable reduction of the erosion rate. The improvement concerns the needling and vowing fibres arrangement only and keeping the same structure of the pitch fibres - the main heat conducting component of NB31. The needling and the vowing fibres of the improved structure provide the armour stiffness, comparable to that of NB31. Numerical simulation of erosion for CFC with the improved structure has confirmed that the erosion rate is four to five times lower in comparison with that of NB31

Economy and development of heating station enterprises managed by forest owners; Metsaenomistajien laempoeyrittaemisen talous ja kehittaeminen

Energy Technology Data Exchange (ETDEWEB)

Tuomi, S [Work Efficiency Inst., Rajamaeki (Finland)

1997-12-01

Private heating enterprises are a new form of heat generation for municipalities in Finland. In this type the entrepreneur acquires the fuel and takes care of the operation and monitoring of the heating station. The recompense is paid on the basis of the heat amount produced to avoid problems related to i.e. the energy content and quality of the fuel. The price of heat is typically bound with that of light fuel oil. Agreements based on the price development of district heat and chips are also used. In 1996 there were 36 such heating enterprises in operation in Finland, their total efficiency being 11.5 MW. The aim of the project is to improve the feasibility of various forms of heating enterprises and to start new heating enterprises. The feasibility is studied both from the viewpoint of the entrepreneur and the municipality. The feasibility is improved by developing production chains of heating enterprises and the operability of the heating stations. Establishment of new heating enterprises is promoted by producing and disseminating information to possible entrepreneurs and municipalities. (orig.)

Effect of hydrogen peroxide on improving the heat stability of whey protein isolate solutions.

Science.gov (United States)

Sutariya, Suresh; Patel, Hasmukh

2017-05-15

Whey protein isolate (WPI) solutions (12.8%w/w protein) were treated with varying concentrations of H 2 O 2 in the range of 0-0.144 H 2 O 2 to protein ratios (HTPR) by the addition of the required quantity of H 2 O 2 and deionized water. The samples were analyzed for heat stability, rheological properties, denaturation level of β-lactoglobulin (β-LG) and α-lactalbumin (α-LA). The samples treated with H 2 O 2 concentration >0.072 (HTPR) showed significant improvement in the heat stability, and decreased whey protein denaturation and aggregation. The WPI solution treated with H 2 O 2 (>0.072 HTPR) remained in the liquid state after heat treatment at 120°C, whereas the control samples formed gel upon heat treatment. Detailed analysis of these samples suggested that the improvement in the heat stability of H 2 O 2 treated WPI solution was attributed to the significant reduction in the sulfhydryl-disulfide interchange reaction during denaturation of β-LG and α-LA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heat Conduction of Air in Nano Spacing

Directory of Open Access Journals (Sweden)

Zhang Yao-Zhong

2009-01-01

Full Text Available Abstract The scale effect of heat conduction of air in nano spacing (NS is very important for nanodevices to improve their life and efficiency. By constructing a special technique, the changes of heat conduction of air were studied by means of measuring the heat conduction with heat conduction instrument in NS between the hot plate and the cooling plate. Carbon nanotubes were used to produce the nano spacing. The results show that when the spacing is small down to nanometer scale, heat conduction plays a prominent role in NS. It was found that the thickness of air is a non-linear parameter for demarcating the heat conduction of air in NS and the rate of heat conduction in unit area could be regard as a typical parameter for the heat conduction characterization at nanometer scale.

Producing standard damaged DNA samples by heating: pitfalls and suggestions.

Science.gov (United States)

Fattorini, Paolo; Marrubini, Giorgio; Bonin, Serena; Bertoglio, Barbara; Grignani, Pierangela; Recchia, Elisa; Pitacco, Paola; Procopio, Francesca; Cantoni, Carolina; Pajnič, Irena Zupanič; Sorçaburu-Cigliero, Solange; Previderè, Carlo

2018-05-15

Heat-mediated hydrolysis of DNA is a simple and inexpensive method for producing damaged samples in vitro. Despite heat-mediated DNA hydrolysis is being widely used in forensic and clinical validation procedures, the lack of standardized procedures makes it impossible to compare the intra and inter-laboratory outcomes of the damaging treatments. In this work, a systematic approach to heat induced DNA hydrolysis was performed at 70 °C for 0-18 h to test the role both of the hydrolysis buffer and of the experimental conditions. Specifically, a trial DNA sample, resuspended in three different media (ultrapure water, 0.1% DEPC-water and, respectively, TE) was treated both in Eppendorf tubes ("Protocol P") and in Eppendorf tubes provided with screwcaps ("Protocol S"). The results of these comparative tests were assessed by normalization of the qPCR results. DEPC-water increased the degradation of the samples up to about 100 times when compared to the ultrapure water. Conversely, the TE protected the DNA from degradation whose level was about 1700 times lower than in samples treated in ultrapure water. Even the employment of the "Protocol S" affected the level of degradation, by consistently increasing it (up to about 180 times in DEPC-water). Thus, this comparative approach showed that even seemingly apparently trivial and often underestimated parameters modify the degradation level up to 2-3 orders of magnitude. The chemical-physical reasons of these findings are discussed together with the role of potential factors such as enhanced reactivity of CO 2 , ROS, NO x and pressure, which are likely to be involved. Since the intra and inter-laboratory comparison of the outcomes of the hydrolytic procedure is the first step toward its standardization, the normalization of the qPCR data by the UV/qPCR ratio seems to be the simplest and most reliable way to allow this. Finally, the supplying (provided with the commercial qPCR kits) of a DNA sample whose degree of

Analysis of transient heat conduction in a PWR fuel rod by an improved lumped parameter approach

Energy Technology Data Exchange (ETDEWEB)

Dourado, Eneida Regina G. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Cotta, Renato M. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Mecanica; Jian, Su, E-mail: eneidadourado@gmail.com, E-mail: sujian@nuclear.ufrj.br, E-mail: cotta@mecanica.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

2017-07-01

This paper aims to analyze transient heat conduction in a nuclear fuel rod by an improved lumped parameter approach. One-dimensional transient heat conduction is considered, with the circumferential symmetry assumed and the axial conduction neglected. The thermal conductivity and specific heat in the fuel pellet are considered temperature dependent, while the thermophysical properties of the cladding are considered constant. Hermite approximation for integration is used to obtain the average temperature and heat flux in the radial direction. Significant improvement over the classical lumped parameter formulation has been achieved. The proposed model can be also used in dynamic analysis of PWR and nuclear power plant simulators. (author)

Analysis of transient heat conduction in a PWR fuel rod by an improved lumped parameter approach

International Nuclear Information System (INIS)

Dourado, Eneida Regina G.; Cotta, Renato M.; Jian, Su

2017-01-01

This paper aims to analyze transient heat conduction in a nuclear fuel rod by an improved lumped parameter approach. One-dimensional transient heat conduction is considered, with the circumferential symmetry assumed and the axial conduction neglected. The thermal conductivity and specific heat in the fuel pellet are considered temperature dependent, while the thermophysical properties of the cladding are considered constant. Hermite approximation for integration is used to obtain the average temperature and heat flux in the radial direction. Significant improvement over the classical lumped parameter formulation has been achieved. The proposed model can be also used in dynamic analysis of PWR and nuclear power plant simulators. (author)

Lipolytic Changes in Fermented Sausages Produced with Turkey Meat: Effects of Starter Culture and Heat Treatment

OpenAIRE

Karslo?lu, Bet?l; ?i?ek, ?mran Ensoy; Kolsarici, Nuray; Cando?an, Kezban

2014-01-01

In this study, the effects of two different commercial starter culture mixes and processing methodologies (traditional and heat process) on the lipolytic changes of fermented sausages manufactured with turkey meat were evaluated during processing stages and storage. Free fatty acid (FFA) value increased with fermentation and during storage over 120 d in all fermented sausage groups produced with both processing methodologies (p

Performance of heat engines with non-zero heat capacity

International Nuclear Information System (INIS)

Odes, Ron; Kribus, Abraham

2013-01-01

Highlights: ► Finite heat capacity is a second irreversibility mechanism in addition to thermal resistance. ► Heat capacity introduces thermal transients and reverse heat flow. ► Engine maximum power and efficiency are lower for finite heat capacity. ► Implementing the optimal engine cycle requires active control. - Abstract: The performance of a heat engine is analyzed subject to two types of irreversibility: a non-zero heat capacity, together with the more common finite heat transfer rate between the engine and the external heat reservoirs. The heat capacity represents an engine body that undergoes significant temperature variations during the engine cycle. An option to cut off the heat exchange between the engine and the external surrounding for part of the engine cycle is also explored. A variational approach was taken to find the engine’s internal temperature profile (which defines the internal thermodynamic cycle) that would produce maximum power. The maximum power is shown to be lower than the case of zero heat capacity, due to a loss of heat that is stored in the engine body and then lost, bypassing the thermodynamic cycle. The maximum efficiency and the efficiency at maximum power are also lower than the zero heat capacity case. Similar to the Curzon–Ahlborn analysis, power can be traded for increased efficiency, but for high heat capacity, the range of efficiency that is available for such a trade is diminished. Isolating the engine during part of the cycle reduces maximum power, but the efficiency at maximum power and the maximum efficiency are improved, due to better exploitation of heat stored in the engine body. This might be useful for real engines that are limited by the internal energy change during a single engine cycle or by the operating frequency, leading to a broader power–efficiency curve.

Heat recovery from a cement plant with a Marnoch Heat Engine

International Nuclear Information System (INIS)

Saneipoor, P.; Naterer, G.F.; Dincer, I.

2011-01-01

This paper examines the performance of a new Marnoch Heat Engine (MHE) that recovers waste heat from within a typical cement plant. Two MHE units with compressed air as the working fluid are installed to recover the waste heat. The first unit on the main stack has four pairs of shell and tube heat exchangers. The second heat recovery unit is installed on a clinker quenching system. This unit operates with three pairs of shell and tube heat exchangers. The recovered heat is converted to electricity through the MHE system and used internally within the cement plant. A predictive model and results are presented and discussed. The results show the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant. The new heat recovery system increases the efficiency of the cement plant and lowers the CO 2 emissions from the clinker production process. Moreover, it reduces the amount of waste heat to the environment and lowers the temperature of the exhaust gases. - Highlights: → This paper examines the thermodynamic performance of a new Marnoch Heat Engine (MHE) that recovers waste heat to produce electricity and improve the operating efficiency of a typical cement plant. → The first unit of the MHE on the main stack has four pairs of shell and tube heat exchangers and the second heat recovery unit is installed on a clinker quenching system. → Both predicted and experimental results demonstrate the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant.

Sales promotion and utilization of fuel. Engineering service of the heat industry for industrial companies

Energy Technology Data Exchange (ETDEWEB)

Schoen, E. (Ruhrgas A.G., Essen (Germany, F.R.). Abt. E-F)

1978-01-01

The contribution illustrates, from the industrial viewpoint, how one may produce process heat rationally and make optimum use of it using natural gas and how competing fuels can be supplanted. The heat economy engineering activities of a modern gas supply undertaking and a few practical examples to improve the industrial produce structure are shown.

A study of the improvement of the district heat price cap system

Energy Technology Data Exchange (ETDEWEB)

Yoo, S.J. [Korea Energy Economics Institute, Euiwang (Korea)

2001-11-01

This study proposes revision of the price cap mechanism applied to the district heating company, which was introduced in 1999. The revision aims at the provision of the incentives to lower the production cost to the heat producers and preventing the monopoly price from being charged to the consumer. It is proposed to extend the application period of the price cap to 3 or 5 years. 3 year application period is recommended because of lack of the experiences of the price cap mechanism and information of its performance in the public utility industries in Korea. The calculation of the price cap is better to be set based upon the minimum of the full cost of heat production in the last year of the previous application periods or the prices actually charged to the consumer during the previous application period. As the opportunity cost of the equity capital, the interest rate of the 5 year government bond or the actual interest cost of the debt financed capital is recommended to increase the share of the equity capital and to reflect the investment risk of the district heating industry. Production efficiency index applicable to the district heating company is estimated with 3 different methods. Among three different results, 3% is the first choice from a conservative perspective. It is also recommended to adjust production efficiency index as the data are accumulated and to be implemented with a profit sharing mechanism between the consumer and the monopoly supplier. In application of the price index, producer price index is applicable if the price cap is calculated from the full production cost. consumer price index is applicable if the price cap is set from the previous year's actual district heat prices (tariffs). Transfer of the ownership either by transferring stocks or by asset selling could affect the price cap determined by the full cost of the district heat production. In order to keep the consumer's welfare from being decreased, it is necessary to set

Solar heat storages in district heating networks

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-15

This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

Low-Cost Gas Heat Pump for Building Space Heating

Energy Technology Data Exchange (ETDEWEB)

Garrabrant, Michael [Stone Mountain Technologies, Inc., Johnson City, TN (United States); Keinath, Christopher [Stone Mountain Technologies, Inc., Johnson City, TN (United States)

2016-10-11

, which will allow for improved load matching. In addition, the energy savings analysis showed that a house in Albany, NY, Chicago, IL and Minneapolis, MN would save roughly 32, 28.5 and 36.5 MBtu annually when compared to a 100% efficient boiler, respectively. The gas absorption heat pump achieves this performance by using high grade heat from the combustion of natural gas in combination with low grade heat extracted from the ambient to produce medium grade heat suitable for space and water heating. Expected product features include conventional outdoor installation practices, 4:1 modulation, and reasonable economic payback. These factors position the technology to gain significant market penetration, resulting in a large reduction of energy use and greenhouse gas emissions for residential space heating.

Hybrid Ground-Source Heat Pump Installations: Experiences, Improvements, and Tools

Energy Technology Data Exchange (ETDEWEB)

Scott Hackel; Amanda Pertzborn

2011-06-30

One innovation to ground-source heat pump (GSHP, or GHP) systems is the hybrid GSHP (HyGSHP) system, which can dramatically decrease the first cost of GSHP systems by using conventional technology (such as a cooling tower or a boiler) to meet a portion of the peak heating or cooling load. This work uses three case studies (two cooling-dominated, one heating-dominated) to demonstrate the performance of the hybrid approach. Three buildings were studied for a year; the measured data was used to validate models of each system. The models were used to analyze further improvements to the hybrid approach, and establish that this approach has positive impacts, both economically and environmentally. Lessons learned by those who design and operate the systems are also documented, including discussions of equipment sizing, pump operation, and cooling tower control. Finally, the measured data sets and models that were created during this work are described; these materials have been made freely available for further study of hybrid systems.

Improved spacers for high temperature gas-cooled heat exchangers

Energy Technology Data Exchange (ETDEWEB)

Nordstroem, L A [Swiss Federal Institute for Reactor Research, Wuerenlingen (Switzerland)

1984-07-01

Experimental and analytical investigations in the field of heat exchanger thermohydraulics have been performed at EIR for many years, Basic studies have been carried out on heat transfer and pressure loss for tube bundles of different geometries and tube surfaces. As a part of this overall R+D programme for heat exchangers, investigations have been carried out on spacer pressure loss in bundles with longitudinal flow. An analytical spacer pressure loss model was developed which could handle different types of subchannel within the bundle. The model has been evaluated against experiments, using about 25 spacers of widely differing geometries. In a gas-cooled reactor it is important to keep the pressure loss over the primary circuit heat exchangers to a minimum. In exchangers with grid spacers these contribute a significant proportion of the overall bundle losses. For example, in the HHT Recuperator, with a shell-side pressure loss of 3.5 % of the inlet pressure, the spacers cause about one half of this loss. Reducing the loss to, say, 2.5 % results in an overall increase in plant efficiency by more than 1 % - a significant improvement Preliminary analysis identified 5 geometries in particular which were chosen for experimental evaluation as part of a joint project with the SULZER Company, to develop a low pressure-loss spacer for HHT heat exchangers (longitudinal counter-flow He/He and He/H{sub 2}O designs). The aim of the tests was to verify the low pressure-loss characteristics of these spacer grid types, as well as the quality of the results calculated by the computer code analytical model. The experimental and analytical results are compared in this report.

Power density of piezoelectric transformers improved using a contact heat transfer structure.

Science.gov (United States)

Shao, Wei Wei; Chen, Li Juan; Pan, Cheng Liang; Liu, Yong Bin; Feng, Zhi Hua

2012-01-01

Based on contact heat transfer, a novel method to increase power density of piezoelectric transformers is proposed. A heat transfer structure is realized by directly attaching a dissipater to the piezoelectric transformer plate. By maintaining the vibration mode of the transformer and limiting additional energy losses from the contact interface, an appropriate design can improve power density of the transformer on a large scale, resulting from effective suppression of its working temperature rise. A prototype device was fabricated from a rectangular piezoelectric transformer, a copper heat transfer sheet, a thermal grease insulation pad, and an aluminum heat radiator. The experimental results show the transformer maintains a maximum power density of 135 W/cm(3) and an efficiency of 90.8% with a temperature rise of less than 10 °C after more than 36 h, without notable changes in performance. © 2012 IEEE

Genetics and genomics to improve fertility in high producing dairy cows

NARCIS (Netherlands)

Veerkamp, R.F.; Beerda, B.

2007-01-01

Improving dairy cow fertility by means of genetic selection is likely to become increasingly important, since it is now well established that declining fertility cannot only be arrested by improved management. Profit margins per kg milk produced are decreasing, therefore farmers need to reduce cost

The indicators of energy security of decentralized heating

Directory of Open Access Journals (Sweden)

Elena Vitalyevna Bykova

2013-06-01

Full Text Available In the paper, the new additional indicators of energy security with the purpose to include decentralized heating sector is developed in the work. The structure of the housing stock of the country is analyzed, which includes different types of central heating boilers and CHP, individual gas or electric heating and stove heating.The analysis of the existing thermal supply (per unit area and per capita living for each sector is carried out. It is found that heat consumed in the residential sector with central heating from CHP and boilers is significantly higher of heat consumed in other sectors. The missing amount of heat energy, which can be produced in two ways, is calculated. Part of the deficit heat can be produced at existing sources that are not loaded enough to the nominal parameters at the moment. The second part can be obtained from small new sources (for inhabited localities that do not have a centralized heat supply infrastructure. New indicators complement the system of indicators to be used to analyze and monitoring the level of Moldova's energy security. They allowed including decentralized heat supply sector, which is not reflected in the official statistics. At the same, the calculation methodology has been improved and the overall integral indicator of the energy security level, which was even more crisis than previously thought.

A Study on the Improvement Effect and Field Applicability of the Deep Soft Ground by Ground Heating Method

Directory of Open Access Journals (Sweden)

Mincheol Park

2018-05-01

Full Text Available The soft ground in coastal areas should be treated when it needs to be used for the sustainably developed of urban or industrial complex constructions. The ground heating method for soft ground improvement was applied in Eastern Europe in the 1960s, but it was not widely used due to economic and environmental problems. The author developed a device for improving soft ground using an electric heating pipe. This paper investigates the improvement effect and field application of deep soft ground by the ground heating method using the electric heating pipe. Ground heating increases the temperature of the deep soft ground and increases the tip resistance of the static electronic piezo-cone penetration test. Additionally, the pressure of the pore water decreases because the pore water is evaporated due to the ground heating. As a result of the experiment, it was verified that there was an improvement in the effect of deep soft ground by the ground heating method. With ground heating for 96 h, the tip resistance was increased by 61% at a point 0.35 m horizontally away from the electric heat pipe, 22% at 0.97 m, and 2% at 1.31 m. As a result of the field test, it was found that there were no problems in the power supply of the diesel generator and the control panel. It was easy to install the electric heating pipes in the deep soft ground. However, due to boring, the ground was disturbed and water vapor was discharged through this gap. To minimize the discharge of water vapor, it is necessary to drive the electric heating pipe.

Geothermal heat pump

International Nuclear Information System (INIS)

Bruno, R.; Tinti, F.

2009-01-01

In recent years, for several types of buildings and users, the choice of conditioning by heat pump and low enthalpy geothermal reservoir has been increasing in the Italian market. In fact, such systems are efficient in terms of energy and consumption, they can perform, even at the same time, both functions, heating and cooling and they are environmentally friendly, because they do not produce local emissions. This article will introduce the technology and will focus on critical points of a geothermal field design, from actual practice, to future perspectives for the geo exchanger improvement. Finally, the article presents a best practice case in Bologna district, with an economic analysis showing the convenience of a geothermal heat pump. Conclusions of the real benefits of these plants can be drawn: compared to a non-negligible initial cost, the investment has a pay-back period almost always acceptable, usually less than 10 years. [it

Improving the livelihoods of wool producers in a sustainable manner ...

African Journals Online (AJOL)

Improving the livelihoods of wool producers in a sustainable manner by optimizing the woolled sheep production systems within the communal farming area of the Eastern Cape. “A vision that is future directed”

The isothermal conductivity improvement in zirconia-based ceramics under 24 GHz microwave heating

International Nuclear Information System (INIS)

Kishimoto, Akira; Ayano, Keiko; Teranishi, Takashi; Hayashi, Hidetaka

2014-01-01

Abstract Under 24-GHz millimetre-wave irradiation heating ionic conductivity of zirconia base ceramics was up to 20 times higher than that of a conventionally-heated sample at the same temperature of 400 °C. The degree of enhancement could be altered by changing the stabilising atom from Y to Yb. Enhancement of ionic conduction was prominent in the setup condition of larger self-heating ratio and larger MMW absorbing materials. The isothermal improvement of ionic conductivity under MMW irradiation would be ascribed to the non-thermal effect. - Highlights: • Under millimetre-wave irradiation heating ionic conductivity of zirconia ceramics was examined. • It was up to 20 times higher than that of a conventionally heating condition. • The activation process was examined in relation to the non-thermal effects. • The operation temperature could be lowered while maintaining the ionic conductivity

A Study on Infrared Local Heat Treatment for AA5083 to Improve Formability and Automotive Part Forming

Science.gov (United States)

Lee, Eun-Ho; Yang, Dong-Yol; Ko, SeJin

2017-10-01

Automotive industries are increasingly employing aluminum alloys for auto parts to reduce vehicle weight. However, the low formability of aluminum alloys has been an obstacle to their application. To resolve the formability problem, some studies involving heat treatments under laboratory conditions have been reported. However, for industrial applications, the heat treatment sequence, heating energy efficiency, and a commercial part test should be studied. This work shows an infrared (IR) local heat treatment, heating only small areas where the heat treatment is required, for an aluminum alloy to improve the formability with a reduction of heating energy. The experiment shows that the formability drastically increases when the aluminum alloy is heat treated between two forming stages, referred to as intermediate heat treatment. The microstructures of the test pieces are evaluated to identify the cause of the increase in the formability. For an industrial application, an aluminum tailgate, which cannot be manufactured without heat treatment, was successfully manufactured by the IR local heat treatment with a reduction of energy. A simulation was also conducted with a stress-based forming limit diagram, which is not affected by the strain path and heat treatment histories. The simulation gives a good prediction of the formability improvement.

Plasma treatment of heat-resistant materials

International Nuclear Information System (INIS)

Vlasov, V A; Kosmachev, P V; Skripnikova, N K; Bezukhov, K A

2015-01-01

Refractory lining of thermal generating units is exposed to chemical, thermal, and mechanical attacks. The degree of fracture of heat-resistant materials depends on the chemical medium composition, the process temperature and the material porosity. As is known, a shortterm exposure of the surface to low-temperature plasma (LTP) makes possible to create specific coatings that can improve the properties of workpieces. The aim of this work is to produce the protective coating on heat-resistant chamotte products using the LTP technique. Experiments have shown that plasma treatment of chamotte products modifies the surface, and a glass-ceramic coating enriched in mullite is formed providing the improvement of heat resistance. For increasing heat resistance of chamotte refractories, pastes comprising mixtures of Bacor, alumina oxide, and chamot were applied to their surfaces in different ratios. It is proved that the appropriate coating cannot be created if only one of heat-resistant components is used. The required coatings that can be used and recommended for practical applications are obtained only with the introduction of powder chamot. The paste composition of 50% chamot, 25% Bacor, and 25% alumina oxide exposed to plasma treatment, has demonstrated the most uniform surface fusion. (paper)

Heat stress management program improving worker health and operational effectiveness: a case study.

Science.gov (United States)

Huss, Rosalyn G; Skelton, Scott B; Alvis, Kimberly L; Shane, Leigh A

2013-03-01

Heat stress monitoring is a vital component of an effective health and safety program when employees work in exceptionally warm environments. Workers at hazardous waste sites often wear personal protective equipment (PPE), which increases the body heat stress load. No specific Occupational Safety and Health Administration (OSHA) regulations address heat stress; however, OSHA does provide several guidance documents to assist employers in addressing this serious workplace health hazard. This article describes a heat stress and surveillance plan implemented at a hazardous waste site as part of the overall health and safety program. The PPE requirement for work at this site, coupled with extreme environmental temperatures, made heat stress a significant concern. Occupational health nurses and industrial hygienists developed a monitoring program for heat stress designed to prevent the occurrence of significant heat-related illness in site workers. The program included worker education on the signs of heat-related illness and continuous physiologic monitoring to detect early signs of heat-related health problems. Biological monitoring data were collected before workers entered the exclusion zone and on exiting the zone following decontamination. Sixty-six site workers were monitored throughout site remediation. More than 1,700 biological monitoring data points were recorded. Outcomes included improved worker health and safety, and increased operational effectiveness. Copyright 2013, SLACK Incorporated.

Improved process for producing oil from minerals

Energy Technology Data Exchange (ETDEWEB)

Peck, E B; Tomkins, D G

1946-11-21

In a process for carrying out thermal reactions in the presence of a fluidized solid, the step of preheating the solid feed is described which comprises passing a heated vapor in heat-exchange relation with the fluidized solid under such conditions that the temperature of the fluidized solid is maintained at reaction temperature.

Improving the performance of district heating systems by utilization of local heat boosters

DEFF Research Database (Denmark)

Falcone, A.; Dominkovic, D. F.; Pedersen, A. S.

was to evaluate the possibilities to lower the forward temperature of the heat supply in order to reduce the heat losses of the system. Booster heat pumps are introduced to increase the water temperature close to the final users. A Matlab model was developed to simulate the state of the case study DH network...... was set to minimize the system heat losses. * Corresponding author 0303-1 1 This goal was achieved by lowering the forward temperature to 40°C and relying on the installed heat pumps to boost the water temperature to the admissible value needed for the domestic hot water preparation. Depending......District Heating (DH) plays an important role into the Danish energy green transition towards the future sustainable energy systems. The new, 4 th generation district heating network, the so called Low Temperature District Heating (LTDH), tends to lower the supply temperature of the heat down to 40...

Use of additives to improve the capacity of bituminous mixtures to be heated by means of microwaves

International Nuclear Information System (INIS)

Gallego, J.; Val, M.A. del; Contreras, V.; Páez, A.

2017-01-01

This study examines the potential of adding electric arc furnace slag to bituminous mixtures to be heated by microwaves. The susceptibility of bituminous mixtures to microwave energy is limited and so, in order to improve the energy performance of the heating process, it is necessary to incorporate additives or components to the mixture so as to improve the capacity for microwave heating. The article presents the results of adding various components, (steel wool, scrap tire wire, silicon carbide, iron filings) and an alternative aggregate: electric arc furnace slag. According to the results obtained in the laboratory, slag addition of at least 5% by weight of the bituminous mixture represents the best option for both technical and economic reasons. The results may promote the valorization of this steel industry residue in bituminous mixtures by improving microwave heating response. [es

Improving the Performance of a Semitransparent BIPV by Using High-Reflectivity Heat Insulation Film

Directory of Open Access Journals (Sweden)

Huei-Mei Liu

2016-01-01

Full Text Available Currently, standard semitransparent photovoltaic (PV modules can largely replace architectural glass installed in the windows, skylights, and facade of a building. Their main features are power generation and transparency, as well as possessing a heat insulating effect. Through heat insulation solar glass (HISG encapsulation technology, this study improved the structure of a typical semitransparent PV module and explored the use of three types of high-reflectivity heat insulation films to form the HISG building-integrated photovoltaics (BIPV systems. Subsequently, the authors analyzed the influence of HISG structures on the optical, thermal, and power generation performance of the original semitransparent PV module and the degree to which enhanced performance is possible. The experimental results indicated that the heat insulation performance and power generation of HISGs were both improved. Selecting an appropriate heat insulation film so that a larger amount of reflective solar radiation is absorbed by the back side of the HISG can yield greater enhancement of power generation. The numerical results conducted in this study also indicated that HISG BIPV system not only provides the passive energy needed for power loading in a building, but also decreases the energy consumption of the HVAC system in subtropical and temperate regions.

Nonlocal heat transport and improved target design for x-ray heating studies at x-ray free electron lasers

Science.gov (United States)

Hoidn, Oliver; Seidler, Gerald T.

2018-01-01

The extremely high-power densities and short durations of single pulses of x-ray free electron lasers (XFELs) have opened new opportunities in atomic physics, where complex excitation-relaxation chains allow for high ionization states in atomic and molecular systems, and in dense plasma physics, where XFEL heating of solid-density targets can create unique dense states of matter having temperatures on the order of the Fermi energy. We focus here on the latter phenomena, with special emphasis on the problem of optimum target design to achieve high x-ray heating into the warm dense matter (WDM) state. We report fully three-dimensional simulations of the incident x-ray pulse and the resulting multielectron relaxation cascade to model the spatial energy density deposition in multicomponent targets, with particular focus on the effects of nonlocal heat transport due to the motion of high energy photoelectrons and Auger electrons. We find that nanoscale high-Z /low-Z multicomponent targets can give much improved energy density deposition in lower-Z materials, with enhancements reaching a factor of 100. This has three important benefits. First, it greatly enlarges the thermodynamic parameter space in XFEL x-ray heating studies of lower-Z materials. Second, it allows the use of higher probe photon energies, enabling higher-information content x-ray diffraction (XRD) measurements such as in two-color XFEL operations. Third, while this is merely one step toward optimization of x-ray heating target design, the demonstration of the importance of nonlocal heat transport establishes important common ground between XFEL-based x-ray heating studies and more traditional laser plasma methods.

An improved unit decommitment algorithm for combined heat and power systems

DEFF Research Database (Denmark)

Rong, Aiying; Lahdelma, R.; Grunow, Martin

2009-01-01

can decommit (switch off) the least cost-efficient plants properly. The improved initial solution for the committed plants is generated by a heuristic procedure. The heuristic procedure utilizes both the Lagrangian relaxation principle that relaxes the system-wide (heat and power) demand constraints...... cases. The maximum improvement is 11.3% and the maximum degradation is only 0.04% (only two sub-cases out of 216 sub-cases) with an average improvement of 0.3-0.5%, for different planning horizons. Moreover, IUD is more efficient (1.1-3 times faster on average) than UD. (C) 2008 Elsevier B.V. All rights...

Food crops face rising temperatures: An overview of responses, adaptive mechanisms, and approaches to improve heat tolerance

Directory of Open Access Journals (Sweden)

Neeru Kaushal

2016-12-01

Full Text Available The rising temperatures are resulting in heat stress for various agricultural crops to limit their growth, metabolism, and leading to significant loss of yield potential worldwide. Heat stress adversely affects normal plant growth and development depending on the sensitivity of each crop species. Each crop species has its own range of temperature maxima and minima at different developmental stages beyond which all these processes get inhibited. The reproductive stage is on the whole more sensitive to heat stress, resulting in impaired fertilization to cause abortion of flowers. During seed filling, heat stress retards seed growth by affecting all the biochemical events to reduce seed size. Unfavorable temperature may significantly affect photosynthesis, respiration, water balance, and membrane stability of leaves. To combat heat stress, plants acquire various defense mechanisms for their survival such as maintaining membrane stability, and scavenging reactive oxygen species by generating antioxidants and stress proteins. Thermo-tolerance can be improved by the accumulation of various compounds of low molecular mass known as thermo-protectants as well as phyto-hormones. Exogenous application of these molecules has benefited plants growing under heat stress. Alternatively, transgenic plants over-expressing the enzymes catalyzing the synthesis of these molecules may be raised to increase their endogenous levels to improve heat tolerance. In recent times, various transgenics have been developed with improved thermo-tolerance having potential benefits for inducing heat tolerance in food crops. Updated information about of the effects of heat stress on various food crops and their responses as well as adaptive mechanisms is reviewed here.

Fuzzy multivariable control of domestic heat pumps

International Nuclear Information System (INIS)

Underwood, C.P.

2015-01-01

Poor control has been identified as one of the reasons why recent field trials of domestic heat pumps in the UK have produced disappointing results. Most of the technology in use today uses a thermostatically-controlled fixed speed compressor with a mechanical expansion device. This article investigates improved control of these heat pumps through the design and evaluation of a new multivariable fuzzy logic control system utilising a variable speed compressor drive with capacity control linked through to evaporator superheat control. A new dynamic thermal model of a domestic heat pump validated using experimental data forms the basis of the work. The proposed control system is evaluated using median and extreme daily heating demand profiles for a typical UK house compared with a basic thermostatically-controlled alternative. Results show good tracking of the heating temperature and superheat control variables, reduced cycling and an improvement in performance averaging 20%. - Highlights: • A new dynamic model of a domestic heat pump is developed and validated. • A new multivariable fuzzy logic heat pump control system is developed/reported. • The fuzzy controller regulates both plant capacity and evaporator superheat degree. • Thermal buffer storage is also considered as well as compressor cycling. • The new controller shows good variable tracking and a reduction in energy of 20%.

Non-standard model for electron heat transport for multidimensional hydrodynamic codes

Energy Technology Data Exchange (ETDEWEB)

Nicolai, Ph.; Busquet, M.; Schurtz, G. [CEA/DAM-Ile de France, 91 - Bruyeres Le Chatel (France)

2000-07-01

In simulations of laser-produced plasma, modeling of heat transport requires an artificial limitation of standard Spitzer-Haerm fluxes. To improve heat conduction processing, we have developed a multidimensional model which accounts for non-local features of heat transport and effects of self-generated magnetic fields. This consistent treatment of both mechanisms has been implemented in a two-dimensional radiation-hydrodynamic code. First results indicate good agreements between simulations and experimental data. (authors)

Non-standard model for electron heat transport for multidimensional hydrodynamic codes

International Nuclear Information System (INIS)

Nicolai, Ph.; Busquet, M.; Schurtz, G.

2000-01-01

In simulations of laser-produced plasma, modeling of heat transport requires an artificial limitation of standard Spitzer-Haerm fluxes. To improve heat conduction processing, we have developed a multidimensional model which accounts for non-local features of heat transport and effects of self-generated magnetic fields. This consistent treatment of both mechanisms has been implemented in a two-dimensional radiation-hydrodynamic code. First results indicate good agreements between simulations and experimental data. (authors)

Utilising heat from nuclear waste for space heating

International Nuclear Information System (INIS)

Deacon, D.

1982-01-01

A heating unit utilising the decay heat from irradiated material comprises a storage envelope for the material associated with a heat exchange system, means for producing a flow of air over the heat exchange system to extract heat from the material, an exhaust duct capable of discharging the heated air to the atmosphere, and means for selectively diverting at least some of the heated air to effect the required heating. With the flow of air over the heat exchange system taking place by a natural thermosyphon process the arrangement is self regulating and inherently reliable. (author)

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

Advanced heat pumps and their economic aspects. The case for super heat pump

International Nuclear Information System (INIS)

Yabe, Akira; Akiya, Takaji

1996-01-01

The results of the economic evaluation of the Super Heat Pump Energy Accumulation System project in Japan are reviewed. It is reported that although the initial costs of super heat pumps are higher than those of conventional systems, the calculated operating costs of a unit thermal energy produced by a super heat pump is reduced considerably. All the various system concepts with thermal/chemical storage were evaluated economically with the exception of the high temperature thermal storage systems using salt ammonia complexes and solvation. These latter systems were not further developed as pilot plants. It is advocated to accelerate the introduction of super heat pumps by facilitating their market introduction. Actual clathrate chemical storage systems have shown that the annual costs are comparable to those of an ice storage system. Clathrate systems will find their way in the market. It is concluded that most of the super heat pump systems and clathrate storage systems will be economic in the future. A big challenge however still exists in further improving the cost effectiveness of heat storage in tanks by reducing their size dramatically (to 1/10th)

Numerical analysis of high-power broad-area laser diode with improved heat sinking structure using epitaxial liftoff technique

Science.gov (United States)

Kim, Younghyun; Sung, Yunsu; Yang, Jung-Tack; Choi, Woo-Young

2018-02-01

The characteristics of high-power broad-area laser diodes with the improved heat sinking structure are numerically analyzed by a technology computer-aided design based self-consistent electro-thermal-optical simulation. The high-power laser diodes consist of a separate confinement heterostructure of a compressively strained InGaAsP quantum well and GaInP optical cavity layers, and a 100-μm-wide rib and a 2000-μm long cavity. In order to overcome the performance deteriorations of high-power laser diodes caused by self-heating such as thermal rollover and thermal blooming, we propose the high-power broad-area laser diode with improved heat-sinking structure, which another effective heat-sinking path toward the substrate side is added by removing a bulk substrate. It is possible to obtain by removing a 400-μm-thick GaAs substrate with an AlAs sacrificial layer utilizing well-known epitaxial liftoff techniques. In this study, we present the performance improvement of the high-power laser diode with the heat-sinking structure by suppressing thermal effects. It is found that the lateral far-field angle as well as quantum well temperature is expected to be improved by the proposed heat-sinking structure which is required for high beam quality and optical output power, respectively.

Improvements in or relating to devices for conducting excess heat away from heat sources

International Nuclear Information System (INIS)

Cooke-Yarborough, E.H.

1976-01-01

Reference is made to radioisotope powered heat engines. Should such an engine stop working for any reason the radioisotope heat source will continue to generate heat, and this may cause overheating and possible damage to the engine as well as the heat source. A device is described for conducting excess heat from the heat source to a heat sink but which in normal operation of the engine will impede heat conduction and so reduce thermal losses. The device may be used to support and/or locate the heat source. Constructional and operational details are given. (U.K.)

Confinement improvement in high-ion temperature plasmas heated with high-energy negative-NBI in LHD

International Nuclear Information System (INIS)

Takeiri, Y.; Morita, S.; Ikeda, K.

2006-10-01

The increase in the ion temperature due to transport improvement has been observed in plasmas heated with high-energy negative-NBI, in which electrons are dominantly heated, in Large Helical Device (LHD). When the centrally focused ECRH is superposed on the NBI plasma, the ion temperature is observed to rise, accompanied by formation of the electron-ITB. This is ascribed to the ion transport improvement with the transition to the neoclassical electron root with a positive radial electric field. In high-Z plasmas, the ion temperature is increased with an increase in the ion heating power, and reaches 13.5keV. The central ion temperature increases with an increase in a gradient of the electron temperature in an outer plasma region of ρ=0.8, suggesting the ion transport improvement in the outer plasma region induced by the neoclassical electron root. These results indicate the effectiveness of the electron-root scenario for obtaining high-ion temperature plasmas in helical systems. (author)

District heating in Switzerland

International Nuclear Information System (INIS)

Herzog, F.

1991-01-01

District heating has been used in Switzerland for more than 50 years. Its share of the heat market is less than 3% today. An analysis of the use of district heating in various European countries shows that a high share of district heating in the heat market is always dependent on ideal conditions for its use. Market prospects and possible future developments in the use of district heating in Switzerland are described in this paper. The main Swiss producers and distributors of district heating are members of the Association of District Heating Producers and Distributors. This association supports the installation of district heating facilities where ecological, energetical and economic aspects indicate that district heating would be a good solution. (author) 2 tabs., 6 refs

Complex Heat Exchangers for Improved Performance

Science.gov (United States)

Bran, Gabriela Alejandra

After a detailed literature review, it was determined that there was a need for a more comprehensive study on the transient behavior of heat exchangers. Computational power was not readily available when most of the work on transient heat exchangers was done (1956 - 1986), so most of these solutions have restrictions, or very specific assumptions. More recently, authors have obtained numerical solutions for more general problems (2003 - 2013), but they have investigated very specific conditions, and cases. For a more complex heat exchanger (i.e. with heat generation), the transient solutions from literature are no longer valid. There was a need to develop a numerical model that relaxes the restrictions of current solutions to explore conditions that have not been explored. A one dimensional transient heat exchanger model was developed. There are no restrictions on the fluids and wall conditions. The model is able to obtain a numerical solution for a wide range of fluid properties and mass flow rates. Another innovative characteristic of the numerical model is that the boundary and initial conditions are not limited to constant values. The boundary conditions can be a function of time (i.e. sinusoidal signal), and the initial conditions can be a function of position. Four different cases were explored in this work. In the first case, the start-up of a system was investigated where the whole system is assumed to be at the same temperature. In the second case, the new steady state in case one gets disrupted by a smaller inlet temperature step change. In the third case, the new steady state in case one gets disrupted by a step change in one of the mass flow rates. The response of these three cases show that there are different transient behaviors, and they depend on the conditions imposed on the system. The fourth case is a system that has a sinusoidal time varying inlet temperature for one of the flows. The results show that the sinusoidal behavior at the inlet

Heating and conduction in laser-produced plasmas

International Nuclear Information System (INIS)

Shay, H.D.; Zimmerman, G.B.; Nuckolls, J.H.

1974-01-01

A series of experiments conducted by G. McCall of LASL provides important clues concerning the electron distributions heated in the absorption of intense (less than or approximately equal to 10/sup lb/ W/cm 2 ) laser radiation and the thermal transport of energy. Presented here is a tentative interpretation of these experiments obtained from LASNEX calculations. (U.S.)

Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003

International Nuclear Information System (INIS)

Hadorn, J.-C.; Renaud, P.

2003-01-01

In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD+D projects

Development and Application of a Numerical Framework for Improving Building Foundation Heat Transfer Calculations

Science.gov (United States)

Kruis, Nathanael J. F.

Heat transfer from building foundations varies significantly in all three spatial dimensions and has important dynamic effects at all timescales, from one hour to several years. With the additional consideration of moisture transport, ground freezing, evapotranspiration, and other physical phenomena, the estimation of foundation heat transfer becomes increasingly sophisticated and computationally intensive to the point where accuracy must be compromised for reasonable computation time. The tools currently available to calculate foundation heat transfer are often either too limited in their capabilities to draw meaningful conclusions or too sophisticated to use in common practices. This work presents Kiva, a new foundation heat transfer computational framework. Kiva provides a flexible environment for testing different numerical schemes, initialization methods, spatial and temporal discretizations, and geometric approximations. Comparisons within this framework provide insight into the balance of computation speed and accuracy relative to highly detailed reference solutions. The accuracy and computational performance of six finite difference numerical schemes are verified against established IEA BESTEST test cases for slab-on-grade heat conduction. Of the schemes tested, the Alternating Direction Implicit (ADI) scheme demonstrates the best balance between accuracy, performance, and numerical stability. Kiva features four approaches of initializing soil temperatures for an annual simulation. A new accelerated initialization approach is shown to significantly reduce the required years of presimulation. Methods of approximating three-dimensional heat transfer within a representative two-dimensional context further improve computational performance. A new approximation called the boundary layer adjustment method is shown to improve accuracy over other established methods with a negligible increase in computation time. This method accounts for the reduced heat transfer

Integration of Thermoelectric Generators and Wood Stove to Produce Heat, Hot Water, and Electrical Power

Science.gov (United States)

Goudarzi, A. M.; Mazandarani, P.; Panahi, R.; Behsaz, H.; Rezania, A.; Rosendahl, L. A.

2013-07-01

Traditional fire stoves are characterized by low efficiency. In this experimental study, the combustion chamber of the stove is augmented by two devices. An electric fan can increase the air-to-fuel ratio in order to increase the system's efficiency and decrease air pollution by providing complete combustion of wood. In addition, thermoelectric generators (TEGs) produce power that can be used to satisfy all basic needs. In this study, a water-based cooling system is designed to increase the efficiency of the TEGs and also produce hot water for residential use. Through a range of tests, an average of 7.9 W was achieved by a commercial TEG with substrate area of 56 mm × 56 mm, which can produce 14.7 W output power at the maximum matched load. The total power generated by the stove is 166 W. Also, in this study a reasonable ratio of fuel to time is described for residential use. The presented prototype is designed to fulfill the basic needs of domestic electricity, hot water, and essential heat for warming the room and cooking.

Improving thermal performance of an existing UK district heat network: a case for temperature optimization

DEFF Research Database (Denmark)

Tunzi, Michele; Boukhanouf, Rabah; Li, Hongwei

2018-01-01

This paper presents results of a research study into improving energy performance of small-scale district heat network through water supply and return temperature optimization technique. The case study involves establishing the baseline heat demand of the estate’s buildings, benchmarking...... the existing heat network operating parameters, and defining the optimum supply and return temperature. A stepwise temperature optimization technique of plate radiators heat emitters was applied to control the buildings indoor thermal comfort using night set back temperature strategy of 21/18 °C....... It was established that the heat network return temperature could be lowered from the current measured average of 55 °C to 35.6 °C, resulting in overall reduction of heat distribution losses and fuel consumption of 10% and 9% respectively. Hence, the study demonstrates the potential of operating existing heat...

Thermodynamic analysis of a novel dual-loop organic Rankine cycle for engine waste heat and LNG cold

International Nuclear Information System (INIS)

Sung, Taehong; Kim, Kyung Chun

2016-01-01

Highlights: • A novel dual ORC system is designed for engine waste heat and LNG cold. • Exhaust gas and jacket cooling water are considered as heat sources. • LNG and boil-off gas are considered as heat sinks. • ORC loops are optimized to produce the maximum net work output. - Abstract: The marine sector produces a large portion of total air pollution, so the emissions of the engines used must be improved. This can be achieved using a new eco-friendly engine and waste-heat recovery system. A dual-fuel (DF) engine has been introduced for LNG carriers that is eco-friendly and has high thermal efficiency since it uses natural gas as fuel. The thermal efficiency could be further improved with the organic Rankine cycle (ORC). A novel dual-loop ORC system was designed for DF engines. The upper ORC loop recovers waste heat from the exhaust gas, and the bottom ORC loop recovers waste heat from the jacket cooling water and LNG cold. Both ORC loops were optimized to produce the maximum net work output. The optimum simple dual-loop ORC with n-pentane and R125 as working fluids produces an additional power output of 729.1 kW, which is 4.15% of the original engine output. Further system improvement studies were conducted using a recuperator and preheater, and the feasibility of using boil-off gas as a heat sink was analyzed. Optimization of the system configuration revealed that the preheater and recuperator with n-pentane and R125 as working fluids increase the maximum net work output by 906.4 kW, which is 5.17% of the original engine output.

Enhanced performance of high current discharges in JET produced by ICRF heating during the current rise

International Nuclear Information System (INIS)

Bures, M.; Bhatnagar, V.; Christiansen, J.P.

1989-01-01

The performance of high current discharges can be improved by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Long sawtooth-free periods have been obtained which result in a transiently-enhanced discharge performance. High T c (0) = 9-10.5 keV with peaked profile T e (0)/ e > = 3-4 were obtained giving values of N e (0)T e (0) up to 6 x 10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A best value of n Dd (0)T i (0)τ E = 1.65 x 10 20 (m -3 keV s) was achieved. Local transport simulation shows that the electron and ion thermal diffusivities do not differ substantially in the two cases of current-rise (CR) and flat-top (FT) heating, the performance of the central plasma region being enhanced, in the case of current-rise, entirely by the elimination of the sawtooth instability. The maximum D-D reaction rate is enhanced by a factor of 2 compared to the flat-top value. An appreciable part of the reaction rate is attributed to 2nd harmonic deuterium (2ω CD ) heating. In all current-rise discharges radiation amounts to 25-50% of total power and Ζ eff remains roughly constant. (author)

Induction heating of rotating nonmagnetic billet in magnetic field produced by high-parameter permanent magnets

Directory of Open Access Journals (Sweden)

Ivo Doležel

2014-04-01

Full Text Available An advanced way of induction heating of nonmagnetic billets is discussed and modeled. The billet rotates in a stationary magnetic field produced by unmoving high-parameter permanent magnets fixed on magnetic circuit of an appropriate shape. The mathematical model of the problem consisting of two coupled partial differential equations is solved numerically, in the monolithic formulation. Computations are carried out using our own code Agros2D based on a fully adaptive higher-order finite element method. The most important results are verified experimentally on our own laboratory device.

Improvement of high temperature fatigue lifetime in AZ91 magnesium alloy by heat treatment

International Nuclear Information System (INIS)

Mokhtarishirazabad, Mehdi; Azadi, Mohammad; Hossein Farrahi, Gholam; Winter, Gerhard; Eichlseder, Wilfred

2013-01-01

In the present paper, an improvement in high temperature fatigue properties of the AZ91 magnesium alloy with rare earth elements has been obtained by a typical heat treatment, denoted by T6. For this objective, out-of-phase thermo-mechanical fatigue, room temperature and high temperature low cycle fatigue tests are performed to compare lifetimes. Several rare earth elements are initially added to the AZ91 alloy during a gravity casting process in permanent molds. Also, the type of the heat treatment is examined. Results of specimens with only the solution (the T4 heat treatment) and the solution with the ageing process (the T6 heat treatment) are compared under isothermal fatigue loadings. Microstructural investigations are carried out, before and after fatigue experiments to demonstrate the heat treatment effect. Results showed that both low cycle fatigue and thermo-mechanical fatigue of the alloy at high temperatures increases tremendously after the T6 heat treatment. This behavior attributes to the variation of the ductility, which was a result of microstructural changes during the heat treatment and the varying temperature in fatigue tests

Improvement of high temperature fatigue lifetime in AZ91 magnesium alloy by heat treatment

Energy Technology Data Exchange (ETDEWEB)

Mokhtarishirazabad, Mehdi [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Azadi, Mohammad, E-mail: m_azadi@ip-co.com [Fatigue and Wear Workgroup, Irankhodro Powertrain Company (IPCO), Tehran (Iran, Islamic Republic of); Hossein Farrahi, Gholam [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Winter, Gerhard; Eichlseder, Wilfred [Chair of Mechanical Engineering, University of Leoben, Leoben (Austria)

2013-12-20

In the present paper, an improvement in high temperature fatigue properties of the AZ91 magnesium alloy with rare earth elements has been obtained by a typical heat treatment, denoted by T6. For this objective, out-of-phase thermo-mechanical fatigue, room temperature and high temperature low cycle fatigue tests are performed to compare lifetimes. Several rare earth elements are initially added to the AZ91 alloy during a gravity casting process in permanent molds. Also, the type of the heat treatment is examined. Results of specimens with only the solution (the T4 heat treatment) and the solution with the ageing process (the T6 heat treatment) are compared under isothermal fatigue loadings. Microstructural investigations are carried out, before and after fatigue experiments to demonstrate the heat treatment effect. Results showed that both low cycle fatigue and thermo-mechanical fatigue of the alloy at high temperatures increases tremendously after the T6 heat treatment. This behavior attributes to the variation of the ductility, which was a result of microstructural changes during the heat treatment and the varying temperature in fatigue tests.

Improving the fidelity of electrically heated nuclear systems testing using simulated neutronic feedback

International Nuclear Information System (INIS)

Bragg-Sitton, Shannon M.; Godfroy, Thomas J.; Webster, Kenny

2010-01-01

Nonnuclear test platforms and methodologies can be employed to reduce the overall cost, risk and complexity of testing nuclear systems while allowing one to evaluate the operation of an integrated nuclear system within a reasonable timeframe, providing valuable input to the overall system design. In a nonnuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Standard electric test techniques allow one to fully assess thermal, heat transfer, and stress related attributes of a given system, but these approaches fail to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. The integration of thermal hydraulic hardware tests with simulated neutronic response provides a bridge between electrically heated testing and testing with nuclear fuel elements installed. By implementing a neutronic response model to simulate the dynamic response that would be expected in a fueled reactor system, one can better understand system integration issues, characterize integrated system response times and response characteristics, and assess potential design improvements at a relatively small fiscal investment. This paper summarizes the results of initial system dynamic response testing for two electrically heated reactor concepts: a heat pipe-cooled reactor simulator with integrated heat exchanger and a gas-cooled reactor simulator with integrated Brayton power conversion system. Initial applications apply a simplified reactor kinetics model with either a single or an averaged measured state point. Preliminary results demonstrate the applicability of the dynamic test methodology to any reactor type, elucidating the variation in system response characteristics in different reactor concepts. These results suggest a need to further enhance the dynamic test approach by incorporating a more accurate model of the reactor dynamics and improved hardware instrumentation for better state estimation in application of the

Equipment for the emplacement of heat-producing waste in long horizontal boreholes

International Nuclear Information System (INIS)

Young, K.D.; Scully, L.W.; Fisk, A.; deBakker, P.; Friant, J.; Anderson, A.

1983-01-01

Emplacement of heat-producing waste in long horizontal holes may offer several technical and economic advantages over shallow vertical hole emplacement. Less of the host rock suffers damage as a result of drift construction; the heat from the waste can be isolated from the access drifts for long periods of time; and the amount of rock which must be excavated is much less than in traditional disposal scenarios. One of the major reasons that has been used to reject the long hole concept in the past and adhere to the shallow vertical hole concept is the equipment required to drill the holes and to emplace and retrieve the waste. Such equipment does not currently exist. It clearly is more difficult to drill a 600 to 1000 foot horizontal hole, possibly 3 to 4 feet in diameter, and place a canister of waste at the end of it than to drill a 30 foot vertical hole and lower the waste to the bottom. A liner, for emplacement hole stabilization, appears to be feasible by adapting existing technology for concrete slip forming or jacking in a steel liner. The conceptual design of the equipment to drill long horizontal holes, emplace waste and retrieve waste will be discussed. Various options in concept will be presented as well as their advantages and disadvantages. The operating scenario of the selected concept will be described as well as solutions to potential problems encountered

Equipment for the emplacement of heat-producing waste in long horizontal boreholes

International Nuclear Information System (INIS)

Young, K.D.; Fisk, A.; Friant, J.; Scully, L.W.

1983-01-01

Emplacement of heat-producing waste in long horizontal holes may offer several technical and economic advantages over shallow vertical hole emplacement. Less of the host rock suffers damage as a resul of drift construction; the heat from the waste can be isolated from the access drifts for long periods of time; and the amount of rock which must be excavated is much less than in traditional disposal scenarios. One of the major reasons that has been used to reject the long hole concept in the past and adhere to the shallow vertical hole concept is the equipment required to drill the holes and to emplace and retrieve the waste. Such equipment does not currently exist. It clearly is more difficult to drill a 600 to 100 foot horizontal hole, possibly 3 to 4 feet in diameter, and place a canister of waste at the end of it than to drill a 30 foot vertical hole and lower the waste to the bottom. A liner, for emplacement hole stabilization, appears to be feasible by adapting existing technology for concrete slip forming or jacking in a steel liner. The conceptual design of the equipment to drill long horizontal holes, emplace waste and retrieve waste is discussed. Various options in concept are presented as well as their advantages and disadvantages. The operating scenario of the selected concept is described as well as solutions to potential problems encountered

Safety characteristics of small heat producing reactors

International Nuclear Information System (INIS)

Seifritz, W.

1987-10-01

The primary objectives of protection in nuclear power plants are the possibility to shut the reactor down in case of emergency and keep it subcritical in the long run, the existence of a heat sink for post-decay heat removal in order to avoid overheating, let alone core meltdown, and the containment of radioactivity within the barriers designed for this purpose, thus preventing significant activity release. In principle, these objectives can be met in various ways, namely by active, passive or inherent technical safeguards systems. In practice, a mixture of these approaches is employed in almost all cases. What matters in the end is the assessment of the overall concept, not of some outstanding feature. Inherent characteristics are easier to achieve in small reactors. However, also in this case, inherent safety does not mean absolute safety. If inherent safety characteristics were all encompassing, they would have to include self-healing effects. However, inanimate matter is incapable of such self-organization. Consequently, inherent characteristics in nuclear technology by definition should include the increased use of dissipative processes in the thermal part of the plant. (author)

Impact of Improved Heat Sinking of an X-Ray Calorimeter Array on Crosstalk, Noise, and Background Events

Science.gov (United States)

Kilbourne, C. A.; Adams, J. S.; Brekosky, R. P.; Chervenak, J. A.; Chiao, M. P.; Kelley, R. L.; Kelly, D. P.; Porter, F. S.

2011-01-01

The x-ray calorimeter array of the Soft X-ray Spectrometer (SXS) of the Astro-H satellite will incorporate a silicon thermistor array produced during the development of the X-Ray Spectrometer (XRS) of the Suzaku satellite. On XRS, inadequate heat sinking of the array led to several non-ideal effects. The thermal crosstalk, while too small to be confused with x-ray signals, nonetheless contributed a noise term that could be seen as a degradation in energy resolution at high flux. When energy was deposited in the silicon frame around the active elements of the array, such as by a cosmic ray, the resulting pulse in the temperature of the frame resulted in coincident signal pulses on most of the pixels. In orbit, the resolution was found to depend on the particle background rate. In order to minimize these effects on SXS, heat-sinking gold was applied to areas on the front and back of the array die, which was thermally anchored to the gold of its fanout board via gold wire bonds. The thermal conductance from the silicon chip to the fanout board was improved over that of XRS by an order of magnitude. This change was sufficient for essentially eliminating frame events and allowing high-resolution to be attained at much higher counting rates. We will present the improved performance, the measured crosstalk, and the results of the thermal characterization of such arrays.

Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

International Nuclear Information System (INIS)

1982-01-01

The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

CFD Simulation and Experimental Analyses of a Copper Wire Woven Heat Exchanger Design to Improve Heat Transfer and Reduce the Size of Adsorption Beds

Directory of Open Access Journals (Sweden)

John White

2016-02-01

Full Text Available The chief objective of this study is the proposal design and CFD simulation of a new compacted copper wire woven fin heat exchanger and silica gel adsorbent bed used as part of an adsorption refrigeration system. This type of heat exchanger design has a large surface area because of the wire woven fin design. It is estimated that this will help improve the coefficient of performance (COP of the adsorption phase and increase the heat transfer in this system arrangement. To study the heat transfer between the fins and porous adsorbent reactor bed, two experiments were carried out and matched to computational fluid dynamics (CFD results.

Averthermodynamic analysis of waste heat recovery for cooling systems in hybrid and electric vehicles

Energy Technology Data Exchange (ETDEWEB)

Javani, N.; Dincer, I.; Naterer, G.F. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (Canada)], email: nader.javani@uoit.ca

2011-07-01

The transportation sector is a heavy consumer of energy and better energy use is needed to reduce fuel consumption. One way to improve energy usage is to recover waste heat for cabin heating, cooling, or to produce electricity. The aim of this paper is to examine the use of waste heat in hybrid electric vehicles (HEV) and electric vehicles for cooling purposes using an ejector cooling cycle and an absorption cooling cycle. Energy and exergy analyses were conducted using waste heat from the battery pack and the exhaust gases to power the boiler and generator. Results showed that waste energy from the battery pack does not provide enough energy to produce cabin cooling but that exhaust gases can produce 7.32 kW and 7.91 kW cooling loads in the ejector and absorption systems. This study demonstrated that both ejector and absorption systems can reduce energy consumption in vehicles through the use of waste heat from exhaust gases.

Improving the conductivity of single-walled carbon nanotubes films by heat treatment

Energy Technology Data Exchange (ETDEWEB)

Wang Jiaping [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Superfine Microstructures, 1295 Dingxi Road, Shanghai 200050 (China); Sun Jing, E-mail: jingsun@mail.sic.ac.c [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Superfine Microstructures, 1295 Dingxi Road, Shanghai 200050 (China); Gao Lian, E-mail: liangaoc@online.sh.c [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Superfine Microstructures, 1295 Dingxi Road, Shanghai 200050 (China); Liu Yangqiao; Wang Yan; Zhang Jing [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Superfine Microstructures, 1295 Dingxi Road, Shanghai 200050 (China); Kajiura, Hisashi; Li Yongming; Noda, Kazuhiro [Advanced Materials Laboratories, Sony Corporation, Atsugi Tec. No. 2, 4-16-1 Okata Atsugi, Kanagawa 243-0021 (Japan)

2009-10-19

A simple heat treatment method was applied to remove surfactants remaining in the single-walled carbon nanotubes (SWNTs) films at 300 deg. C for 5 h in air. Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and reflected light interference microscope (RLIM) were employed to verify the elimination of surfactants. The comprehensive performance, especially the conductivity, could be improved by more than one order after heat treatment. For example, using SDBS as dispersant, the sheet resistance decreased from 782,600 OMEGA/square to 40,460 OMEGA/square with the transmittance of about 99.5% at 550 nm.

Development of producing equipment of mixed butane-air with low dew point. Energy saving dewatering apparatus and 6A-Gas producing apparatus utilizing vaporization latent heat of butane and potential heat of air

Energy Technology Data Exchange (ETDEWEB)

Komine, Jin; Okada, Hiroto; Taniue, Nobuo; Tanoue, Keiju; Yamada, Tatsuhiko; Maekawa, Hisami; Murakami, Keiji

1988-02-10

A producing equipment of mixed butane-air with low dew point was developed. The dewatering was made during the period from the middle of May to the middle of October with high atmospheric humidity. The production capacity of the mixed gas is 3000 Nm/sup 3/ of 22% of butane and 78% of air per hour. The designed dew point is 18/sup 0/C or less under the pressure of 0.7 kg/cm/sup 2/G. The saturation temperature is 7.5/sup 0/C after the liquid butane is evacuated by a regulating valve. The air introduced into the dehumidifier through finned tubes is cooled to dewater based on those data. The partially vaporized butane is completely gasified by hot water in a vaporizer and mixed with the dewatered air by a venture mixer to produce the mixed butane-air. When the dewatering is incomplete, the spray nozzle must be just exchanged. The dew point of the produced gas was sufficiently below the designed value. The investment cost is low. The total operating cost is reduced by the remarkably decreased fuel cost though the power cost is increased. The noise level is low and the heat control is easy. (11 figs, 4 tabs, 1 photo)

Integration of a wood pellet burner and a Stirling engine to produce residential heat and power

International Nuclear Information System (INIS)

Cardozo, Evelyn; Erlich, Catharina; Malmquist, Anders; Alejo, Lucio

2014-01-01

The integration a Stirling engine with a pellet burner is a promising alternative to produce heat and power for residential use. In this context, this study is focused on the experimental evaluation of the integration of a 20 kW th wood pellet burner and a 1 kW e Stirling engine. The thermal power not absorbed by the engine is used to produce hot water. The evaluation highlights the effects of pellet type, combustion chamber length and cycling operation on the Stirling engine temperatures and thermal power absorbed. The results show that the position of the Stirling engine is highly relevant in order to utilize as much as possible of the radiative heat from the burner. Within this study, only a 5 cm distance change between the Stirling engine and the pellet burner could result in an increase of almost 100 °C in the hot side of the engine. However, at a larger distance, the temperature of the hot side is almost unchanged suggesting dominating convective heat transfer from the hot flue gas. Ash accumulation decreases the temperature of the hot side of the engine after some cycles of operation when a commercial pellet burner is integrated. The temperature ratio, which is the relation between the minimum and maximum temperatures of the engine, decreases when using Ø8 mm wood pellets in comparison to Ø6 mm pellets due to higher measured temperatures on the hot side of the engine. Therefore, the amount of heat supplied to the engine is increased for Ø8 mm wood pellets. The effectiveness of the engine regenerator is increased at higher pressures. The relation between temperature of the hot side end and thermal power absorbed by the Stirling engine is nearly linear between 500 °C and 660 °C. Higher pressure inside the Stirling engine has a positive effect on the thermal power output. Both the chemical and thermal losses increase somewhat when integrating a Stirling engine in comparison to a stand-alone boiler for only heat production. The overall efficiency

The effect of substrate conduction on boiling data on pin-fin heat sinks

International Nuclear Information System (INIS)

McNeil, D.A.; Raeisi, A.H.; Kew, P.A.; Hamed, R.S.

2015-01-01

as the distance from the onset increases. The effect of test-section design is investigated by repeating the analyses with smaller wall thickness and lower wall thermal conductivities. Lower wall thermal conductivity is shown to produce a uniform heat flux distribution at the expense of reduced extended surface effectiveness. Thinner substrate thicknesses are found to give limited improvements. These analyses demonstrate that an applied uniform heat flux to the heat sink base will not result in a uniform heat flux at the solid–liquid interface

Kinetic Hydration Heat Modeling for High-Performance Concrete Containing Limestone Powder

Directory of Open Access Journals (Sweden)

Xiao-Yong Wang

2017-01-01

Full Text Available Limestone powder is increasingly used in producing high-performance concrete in the modern concrete industry. Limestone powder blended concrete has many advantages, such as increasing the early-age strength, reducing the setting time, improving the workability, and reducing the heat of hydration. This study presents a kinetic model for modeling the hydration heat of limestone blended concrete. First, an improved hydration model is proposed which considers the dilution effect and nucleation effect due to limestone powder addition. A degree of hydration is calculated using this improved hydration model. Second, hydration heat is calculated using the degree of hydration. The effects of water to binder ratio and limestone replacement ratio on hydration heat are clarified. Third, the temperature history and temperature distribution of hardening limestone blended concrete are calculated by combining hydration model with finite element method. The analysis results generally agree with experimental results of high-performance concrete with various mixing proportions.

Waste heat recovery from the exhaust of a diesel generator using Rankine Cycle

International Nuclear Information System (INIS)

Hossain, Shekh Nisar; Bari, Saiful

2013-01-01

Highlights: • Diesel engine exhaust contains 40% energy which can be used to produce extra power. • Extra 11% power gained with optimized heat exchangers using water as working fluid. • As a result brake specific fuel consumption improved by 12%. • Parallel arrangement of heat exchangers showed better performance than series. • Optimum working fluid pressure varies with the engine power. - Abstract: Exhaust heat from diesel engines can be an important heat source to provide additional power using a separate Rankine Cycle (RC). In this research, experiments were conducted to measure the available exhaust heat from a 40 kW diesel generator using two ‘off-the-shelf’ heat exchangers. The effectiveness of the heat exchangers using water as the working fluid was found to be 0.44 which seems to be lower than a standard one. This lower performance of the existing heat exchangers indicates the necessity of optimization of the design of the heat exchangers for this particular application. With the available experimental data, computer simulations were carried out to optimize the design of the heat exchangers. Two heat exchangers were used to generate super-heated steam to expand in the turbine using two orientations: series and parallel. The optimized heat exchangers were then used to estimate additional power considering actual turbine isentropic efficiency. The proposed heat exchanger was able to produce 11% additional power using water as the working fluid at a pressure of 15 bar at rated engine load. This additional power resulted into 12% improvement in brake-specific fuel consumption (bsfc). The effects of the working fluid pressure were also investigated to maximize the additional power production. The pressure was limited to 15 bar which was constrained by the exhaust gas temperature. However, higher pressure is possible for higher exhaust gas temperatures from higher capacity engines. This would yield more additional power with further improvements in

Development of a Field Demonstration for Cost-Effective Low-Grade Heat Recovery and Use Technology Designed to Improve Efficiency and Reduce Water Usage Rates for a Coal-Fired Power Plant

Energy Technology Data Exchange (ETDEWEB)

Noble, Russell [Southern Company Services, Incorporated, Birmingham, AL (United States); Dombrowski, K. [AECOM Technical Services, Austin, TX (United States); Bernau, M. [AECOM Technical Services, Austin, TX (United States); Morett, D. [AECOM Technical Services, Austin, TX (United States); Maxson, A. [EPRI, Palo Alto, CA (United States); Hume, S. [EPRI, Palo Alto, CA (United States)

2016-06-30

Coal-based power generation systems provide reliable, low-cost power to the domestic energy sector. These systems consume large amounts of fuel and water to produce electricity and are the target of pending regulations that may require reductions in water use and improvements in thermal efficiency. While efficiency of coal-based generation has improved over time, coal power plants often do not utilize the low-grade heat contained in the flue gas and require large volumes of water for the steam cycle make-up, environmental controls, and for process cooling and heating. Low-grade heat recovery is particularly challenging for coal-fired applications, due in large part to the condensation of acid as the flue gas cools and the resulting potential corrosion of the heat recovery materials. Such systems have also not been of significant interest as recent investments on coal power plants have primarily been for environmental controls due to more stringent regulations. Also, in many regions, fuel cost is still a pass-through to the consumer, reducing the motivation for efficiency improvements. Therefore, a commercial system combining low-grade heat-recovery technologies and associated end uses to cost effectively improve efficiency and/or reduce water consumption has not yet been widely applied. However, pressures from potential new regulations and from water shortages may drive new interest, particularly in the U.S. In an effort to address this issue, the U.S. Department of Energy (DOE) has sought to identify and promote technologies to achieve this goal.

Improvements in or relating to heat exchangers

International Nuclear Information System (INIS)

Linning, D.L.

1976-01-01

A 'tube-in-shell' heat exchanger is described for effecting heat exchange between liquid metal and water. In conventional heat exchangers of this type a condition can arise wherein Na passing through the tube plate at the water inlet end of the heat exchanger may be above the saturation temperature of the water, and although resultant boiling of the water in the region of the tube plate would tend to counter stagnation there is a possibility that sub-cooled boiling associated with stagnation may occur in the central area of the tube plate, and this could be the source of corrosion. The design of heat exchanger described is directed towards a solution of this problem. The heat exchanger comprises an elongated shell having two spaced transverse tube plates sealed to the shell so as to provide end and intermediate chambers. A bundle of spaced parallel heat exchange tubes extends between the tube plates, interconnecting the end chambers with an inlet port for liquid metal flow to one of the end chambers and an outlet port for liquid metal flow from the other of the end chambers, and inlet and outlet ports for flow of water through the intermediate chamber, these ports being at opposite ends of the intermediate chamber. The intermediate chamber has a tube closed to liquid metal flow extending between the tube plates, this tube having an inlet port for water adjacent to the tube plate at the inlet region of the intermediate chamber and an outlet port at the outlet region. This tube has open ends and is laterally supported by neighbouring heat exchange tubes, or alternatively may have closed ends and be end supported by penetration of the tube plates, the inlet and outlet ports for flow of water being perforations in the wall of the tube. (U.K.)

Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

International Nuclear Information System (INIS)

Savulescu, Luciana Elena; Alva-Argaez, Alberto

2008-01-01

The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks

An improved CO_2-based transcritical Rankine cycle (CTRC) used for engine waste heat recovery

International Nuclear Information System (INIS)

Shu, Gequn; Shi, Lingfeng; Tian, Hua; Li, Xiaoya; Huang, Guangdai; Chang, Liwen

2016-01-01

Highlights: • Propose an improved CTRC system (PR-CTRC) for engine waste heat recovery. • The PR-CTRC achieves a significant increase in thermodynamic performance. • The PR-CTRC possesses a strong coupling capability for high and low grade waste heat. • The PR-CTRC uses smaller turbine design parameters than ORC systems. • Total cooling load analysis of combined engine and recovery system was conducted. - Abstract: CO_2-based transcritical Rankine cycle (CTRC) is a promising technology for the waste heat recovery of an engine considering its safety and environment friendly characteristics, which also matchs the high temperature of the exhaust gas and satisfies the miniaturization demand of recovery systems. But the traditional CTRC system with a basic configuration (B-CTRC) has a poor thermodynamic performance. This paper introduces an improved CTRC system containing both a preheater and regenerator (PR-CTRC), for recovering waste heat in exhaust gas and engine coolant of an engine, and compares its performance with that of the B-CTRC system and also with that of the traditional excellent Organic Rankine Cycle (ORC) systems using R123 as a working fluid. The utilization rate of waste heat, total cooling load, net power output, thermal efficiency, exergy loss, exergy efficiency and component size have been investigated. Results show that, the net power output of the PR-CTRC could reach up to 9.0 kW for a 43.8 kW engine, which increases by 150% compared with that of the B-CTRC (3.6 kW). The PR-CTRC also improves the thermal efficiency and exergy efficiency of the B-CTRC, with increases of 184% and 227%, respectively. Compared with the ORC system, the PR-CTRC shows the significant advantage of highly recycling the exhaust gas and engine coolant simultaneously due to the special property of supercritical CO_2’s specific heat capacity. The supercritical property of CO_2 also generates a better heat transfer and flowing performances. Meanwhile, the PR

High-performance heat pipes for heat recovery applications

Science.gov (United States)

Saaski, E. W.; Hartl, J. H.

1980-01-01

Methods to improve the performance of reflux heat pipes for heat recovery applications were examined both analytically and experimentally. Various models for the estimation of reflux heat pipe transport capacity were surveyed in the literature and compared with experimental data. A high transport capacity reflux heat pipe was developed that provides up to a factor of 10 capacity improvement over conventional open tube designs; analytical models were developed for this device and incorporated into a computer program HPIPE. Good agreement of the model predictions with data for R-11 and benzene reflux heat pipes was obtained.

Development of a Wind Directly Forced Heat Pump and Its Efficiency Analysis

Directory of Open Access Journals (Sweden)

Ching-Song Jwo

2013-01-01

Full Text Available The requirements of providing electric energy through the wind-forced generator to the heat pump for water cooling and hot water heating grow significantly by now. This study proposes a new technique to directly adopt the wind force to drive heat pump systems, which can effectively reduce the energy conversion losses during the processes of wind force energy converting to electric energy and electric energy converting to kinetic energy. The operation of heat pump system transfers between chiller and heat that are controlled by a four-way valve. The theoretical efficiency of the traditional method, whose heat pump is directly forced by wind, is 42.19%. The experimental results indicated average value for cool water producing efficiency of 54.38% in the outdoor temperature of 35°C and the indoor temperature of 25°C and the hot water producing efficiency of 52.25% in the outdoor temperature and the indoor temperature both of 10°C. We proposed a method which can improve the efficiency over 10% in both cooling and heating.

A demonstration of the improved efficiency of the canonical coordinates method using nonlinear combined heat and power economic dispatch problems

Science.gov (United States)

Chang, Hung-Chieh; Lin, Pei-Chun

2014-02-01

Economic dispatch is the short-term determination of the optimal output from a number of electricity generation facilities to meet the system load while providing power. As such, it represents one of the main optimization problems in the operation of electrical power systems. This article presents techniques to substantially improve the efficiency of the canonical coordinates method (CCM) algorithm when applied to nonlinear combined heat and power economic dispatch (CHPED) problems. The improvement is to eliminate the need to solve a system of nonlinear differential equations, which appears in the line search process in the CCM algorithm. The modified algorithm was tested and the analytical solution was verified using nonlinear CHPED optimization problems, thereby demonstrating the effectiveness of the algorithm. The CCM methods proved numerically stable and, in the case of nonlinear programs, produced solutions with unprecedented accuracy within a reasonable time.

Heat transfer enhancement

International Nuclear Information System (INIS)

Hasatani, Masanobu; Itaya, Yoshinori

1985-01-01

In order to develop energy-saving techniques and new energy techniques, and also most advanced techniques by making industrial equipment with high performance, heat transfer performance frequently becomes an important problem. In addition, the improvement of conventional heat transfer techniques and the device of new heat transfer techniques are often required. It is most proper that chemical engineers engage in the research and development for enhancing heat transfer. The research and development for enhancing heat transfer are important to heighten heat exchange efficiency or to cool equipment for preventing overheat in high temperature heat transfer system. In this paper, the techniques of enhancing radiative heat transfer and the improvement of radiative heat transfer characteristics are reported. Radiative heat transfer is proportional to fourth power of absolute temperature, and it does not require any heat transfer medium, but efficient heat-radiation converters are necessary. As the techniques of enhancing radiative heat transfer, the increase of emission and absorption areas, the installation of emissive structures and the improvement of radiative characteristics are discussed. (Kako, I.)

Impact of different improvement measures on the thermal performance of a solar collector field for district heating

DEFF Research Database (Denmark)

Bava, Federico; Furbo, Simon

2018-01-01

The paper describes the impact of different measures to improve the thermal performance of a solar heating plant for district heating applications. The impact of the different measures was evaluated through a validated TRNSYS-Matlab model. The model included details such as effect of the flow...... temperature of the collector field, control strategy based on weather forecast and use of different heat transfer fluids. The results showed that accurate input to the control strategy improved the yearly energy output of the plant by about 3%. If accurate input is not technically or economically feasible...... regime in the absorber pipes on the collector efficiency, flow distribution in the collector field, thermal capacity of the pipes and shadows from row to row. The improvement measures included variation of the operating temperatures, accurate input to the control strategy, feedback control on the outlet...

A review of chemical heat pumps, thermodynamic cycles and thermal energy storage technologies for low grade heat utilisation

International Nuclear Information System (INIS)

Chan, C.W.; Ling-Chin, J.; Roskilly, A.P.

2013-01-01

A major cause of energy inefficiency is a result of the generation of waste heat and the lack of suitable technologies for cost-effective utilisation of low grade heat in particular. The market potential for surplus/waste heat from industrial processes in the UK is between 10 TWh and 40 TWh, representing a significant potential resource which has remained unexploited to date. This paper reviews selected technologies suitable for utilisation of waste heat energy, with specific focus on low grade heat, including: (i) chemical heat pumps, such as adsorption and absorption cycles for cooling and heating; (ii) thermodynamic cycles, such as the organic Rankine cycle (ORC), the supercritical Rankine cycle (SRC) and the trilateral cycle (TLC), to produce electricity, with further focus on expander and zeotropic mixtures, and (iii) thermal energy storage, including sensible and latent thermal energy storages and their corresponding media to improve the performance of low grade heat energy systems. - Highlights: ► The review of various thermal technologies for the utilisation of under exploited low grade heat. ► The analyses of the absorption and adsorption heat pumps possibly with performance enhancement additives. ► The analyses of thermal energy storage technologies (latent and sensible) for heat storage. ► The analyses of low temperature thermodynamic cycles to maximise power production.

Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

The inaccuracy of heat transfer characteristics of insulated and non-insulated circular duct while neglecting the influence of heat radiation

International Nuclear Information System (INIS)

Hsien, T.-L.; Wong, K.-L.; Yu, S.-J.

2009-01-01

The non-insulated and insulated ducts are commonly applied in the industries and various buildings, because the heat radiation equation contains the 4th order exponential of temperature which is very complicate in calculations. Most heat transfer experts recognized from their own experiences that the heat radiation effect can be ignored due to the small temperature difference between insulated and non-insulated surface and surroundings. This paper studies in detail to check the inaccuracies of heat transfer characteristics non-insulated and insulated duct by comparing the results between considering and neglecting heat radiation effect. It is found that neglecting the heat radiation effect is likely to produce large errors of non-insulated and thin-insulated ducts in situations of ambient air with low external convection heat coefficients and larger surface emissivity, especially while the ambient air temperature is different from that of surroundings and greater internal fluid convection coefficients. It is also found in this paper that using greater duct surface emissivity can greatly improve the heat exchanger effect and using smaller insulated surface emissivity can obtain better insulation.

Environment-friendly heat supply with natural refrigerants. Large heat pumps use industrial waste heat and waste water; Umweltschonende Waermeversorgung mit natuerlichen Kaeltemitteln. Grosswaermepumpen nutzen industrielle Abwaerme und Abwaesser

Energy Technology Data Exchange (ETDEWEB)

Anon.

2011-01-15

Everywhere, where industrial processes occur or coldness is produced, simultaneously heat is produced. While many private houses use geothermal energy or ambient air for the production of heat, waste water and waste heat prove to be optimal energy sources for the industrial need due to higher output temperatures. By means of large heat pumps the residual heat is used for heating or the supply of hot water for example in local heat supply grids and makes an important contribution to climate protection.

Numerical simulation of a heat pump assisted regenerative solar still with PCM heat storage for cold climates of Kazakhstan

Directory of Open Access Journals (Sweden)

Shakir Yessen

2017-01-01

Full Text Available A numerical model has been proposed in this work for predicting the energy performances of the heat pump assisted regenerative solar still with phase changing material heat storage under Kazakhstan climates. The numerical model is based on energy and mass balance. A new regenerative heat pump configuration with phase changing material heat storage is proposed to improve the performance. A comparison of results has been made between the conventional solar still and heat pump assisted regenerative solar still with phase changing material. The numerical simulation was performed for wide range of ambient temperatures between -30 and 30°C with wide range of solar intensities between 100 and 900 W/m2. The numerical simulation results showed that heat pump assisted regenerative solar still is more energy efficient and produce better yield when compared to the conventional simple solar still. The influences of solar intensity, ambient temperature, different phase changing materials, heat pump operating temperatures are discussed. The predicted values were found to be in good agreement with experimental results reported in literature.

Short-term heat acclimation improves the determinants of endurance performance and 5-km running performance in the heat.

Science.gov (United States)

James, Carl A; Richardson, Alan J; Watt, Peter W; Willmott, Ashley G B; Gibson, Oliver R; Maxwell, Neil S

2017-03-01

This study investigated the effect of 5 days of controlled short-term heat acclimation (STHA) on the determinants of endurance performance and 5-km performance in runners, relative to the impairment afforded by moderate heat stress. A control group (CON), matched for total work and power output (2.7 W·kg -1 ), differentiated thermal and exercise contributions of STHA on exercise performance. Seventeen participants (10 STHA, 7 CON) completed graded exercise tests (GXTs) in cool (13 °C, 50% relative humidity (RH), pre-training) and hot conditions (32 °C, 60% RH, pre- and post-training), as well as 5-km time trials (TTs) in the heat, pre- and post-training. STHA reduced resting (p = 0.01) and exercising (p = 0.04) core temperature alongside a smaller change in thermal sensation (p = 0.04). Both groups improved the lactate threshold (LT, p = 0.021), lactate turnpoint (LTP, p = 0.005) and velocity at maximal oxygen consumption (vV̇O 2max ; p = 0.031) similarly. Statistical differences between training methods were observed in TT performance (STHA, -6.2(5.5)%; CON, -0.6(1.7)%, p = 0.029) and total running time during the GXT (STHA, +20.8(12.7)%; CON, +9.8(1.2)%, p = 0.006). There were large mean differences in change in maximal oxygen consumption between STHA +4.0(2.2) mL·kg -1 ·min -1 (7.3(4.0)%) and CON +1.9(3.7) mL·kg -1 ·min -1 (3.8(7.2)%). Running economy (RE) deteriorated following both training programmes (p = 0.008). Similarly, RE was impaired in the cool GXT, relative to the hot GXT (p = 0.004). STHA improved endurance running performance in comparison with work-matched normothermic training, despite equality of adaptation for typical determinants of performance (LT, LTP, vV̇O 2max ). Accordingly, these data highlight the ergogenic effect of STHA, potentially via greater improvements in maximal oxygen consumption and specific thermoregulatory and associated thermal perception adaptations absent in normothermic training.

Frontier technologies to improve efficiency

International Nuclear Information System (INIS)

Kalhammer, F.R.

1992-01-01

The author discusses conservation technology to improve the efficiency of energy production. Although coal is seen as the largest source of fuel for producing electricity until the year 2040, the heating value of coal is expected to be increased by using Integrated Gasification Combined Cycle (IGCC) technology. Use of fuel cells to produce electricity will be a viable option only if costs can be reduced to make the technology competitive. By coupling IGCC with fuel cells it may be possible to increase total conversion efficiency of coal to electricity at 50%. Photovoltaics technology is more likely to be used in developing countries. Electric utilities target power electronics, lighting fixtures, heat pumps, plasma processing, freeze concentration and application of superconductivity as electricity end use technologies that have the most potential for efficiency improvement. The impact of these technologies in coping with the greenhouse effect was not addressed

USING LIGA BASED MICROFABRICATION TO IMPROVE OVERALL HEAT TRANSFER EFFICIENCY OF PRESSURIZED WATER REACTOR: I. Effects of Different Micro Pattern on Overall Heat Transfer

International Nuclear Information System (INIS)

Zhang, M.; Ibekwe, S.; Li, G.; Pang, S.S.; Lian, K.

2006-01-01

The Pressurized Water Reactors (PWRs in Figure 1) were originally developed for naval propulsion purposes, and then adapted to land-based applications. It has three parts: the reactor coolant system, the steam generator and the condenser. The Steam generator (a yellow area in Figure 1) is a shell and tube heat exchanger with high-pressure primary water passing through the tube side and lower pressure secondary feed water as well as steam passing through the shell side. Therefore, a key issue in increasing the efficiency of heat exchanger is to improve the design of steam generator, which is directly translated into economic benefits. The past research works show that the presence of a pin-fin array in a channel enhances the heat transfer significantly. Hence, using microfabrication techniques, such as LIGA, micro-molding or electroplating, some special microstructures can be fabricated around the tubes in the heat exchanger to increase the heat-exchanging efficiency and reduce the overall size of the heat-exchanger for the given heat transfer rates. In this paper, micro-pin fins of different densities made of SU-8 photoresist are fabricated and studied to evaluate overall heat transfer efficiency. The results show that there is an optimized micro pin-fin configuration that has the best overall heat transfer effects

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...

Industrial Heat Pump for a High Temperature District Heating Application

DEFF Research Database (Denmark)

Poulsen, Claus Nørgaard

by excess thermal energy from thermal solar panels. An industrial heat pump system using the natural refrigerant ammonia, is extracting the thermal energy from the storage when needed, and produce hot water at 85°C, for the district heating grid. The heat pump also acts as contributor to electricity grid...

Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling

CERN Document Server

Barnes, M J; Calatroni, S; Day, H; Ducimetière, L; Garlaschè, M; Gomes Namora, V; Mertens, V; Sobiech, Z; Taborelli, M; Uythoven, J; Weterings, W

2013-01-01

The two LHC injection kicker systems produce an integrated field strength of 1.3 T·m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wakefields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrite yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. Various measures to improve the ferrite cooling have...

Advanced Heat/Mass Exchanger Technology for Geothermal and Solar Renewable Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Greiner, Miles [Univ. of Nevada, Reno, NV (United States); Childress, Amy [Univ. of Nevada, Reno, NV (United States); Hiibel, Sage [Univ. of Nevada, Reno, NV (United States); Kim, Kwang [Univ. of Nevada, Reno, NV (United States); Park, Chanwoo [Univ. of Nevada, Reno, NV (United States); Wirtz, Richard [Univ. of Nevada, Reno, NV (United States)

2014-12-16

Northern Nevada has abundant geothermal and solar energy resources, and these renewable energy sources provide an ample opportunity to produce economically viable power. Heat/mass exchangers are essential components to any energy conversion system. Improvements in the heat/mass exchange process will lead to smaller, less costly (more efficient) systems. There is an emerging heat transfer technology, based on micro/nano/molecular-scale surface science that can be applied to heat/mass exchanger design. The objective is to develop and characterize unique coating materials, surface configurations and membranes capable of accommodating a 10-fold increase in heat/mass exchanger performance via phase change processes (boiling, condensation, etc.) and single phase convective heat/mass transfer.

Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

Energy Technology Data Exchange (ETDEWEB)

Savulescu, Luciana Elena; Alva-Argaez, Alberto [Natural Resources (Canada)

2008-10-15

The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks. (author)

District heating by the Bohunice nuclear power plant

International Nuclear Information System (INIS)

Metke, E.; Skvarka, P.

1984-01-01

Technical and economical aspects of district heating by the electricity generating nuclear plants in Czechoslovakia are discussed. As a first stage of the project, 240 MW thermal power will be supplied using bleeding lines steam from the B-2 nuclear power plant at Jaslovske Bohunice to heat up water at a central station to 130 grad C. The maximal thermal power that can be produced for district heating by WWER type reactors with regular condensation turbines is estimated to be: 465 MW for a WWER-440 reactor with two 220 MWe turbines and 950 MW for a WWER-1000 reactor with a Skoda made 1000 MWe turbine using a three-stage scheme to heat up water from 60 grad C to 150 grad C. The use of satelite heating turbines connected to the steam collector is expected to improve the efficiency. District heating needs will de taken into account for siting of the new power plants

Improvements in or relating to heat exchangers

International Nuclear Information System (INIS)

Graham, L.W.; Sturge, D.W.J.; Ridealgh, F.

1978-01-01

A heat exchanger is described that is suitable for use with high temperature gas cooled reactors in which the heat is used as process heat. The construction which is of necessity of large size, is of much lighter weight than current constructions and is better able to withstand the high operating temperature (up to about 1000 0 C). Carbon fibre reinforced carbon materials are employed as constructional materials. A method of fabrication is described. The heat exchanger comprises a tube or bundle of tubes associated with a header plate, and the tube can be of helical form. The carbon materials may be formed by carbonisation of a thermosetting plastic such as a phenolic resin. The exchanger is rendered substantially impermeable to gas by an infiltration treatment of the carbon material using a cracked hydrocarbon gas. (U.K.)

Improvements in or relating to heat exchangers

Energy Technology Data Exchange (ETDEWEB)

Graham, L W; Sturge, D W.J.; Ridealgh, F

1978-04-05

A heat exchanger is described that is suitable for use with high temperature gas cooled reactors in which the heat is used as process heat. The construction which is of necessity of large size, is of much lighter weight than current constructions and is better able to withstand the high operating temperature (up to about 1000/sup 0/C). Carbon fibre reinforced carbon materials are employed as constructional materials. A method of fabrication is described. The heat exchanger comprises a tube or bundle of tubes associated with a header plate, and the tube can be of helical form. The carbon materials may be formed by carbonisation of a thermosetting plastic such as a phenolic resin. The exchanger is rendered substantially impermeable to gas by an infiltration treatment of the carbon material using a cracked hydrocarbon gas.

Luminaries-level structure improvement of LEDs for heat dissipation ...

Indian Academy of Sciences (India)

the natural convection heat transfer process of LED luminaries is simulated by compu- ... Heat dissipation has become one of the key problems limiting the large ... micro channel heat radiator, are able to reject heat efficiently, they may make LED ... convection heat transfer coefficient, for example, adopting finned surface to ...

Use of integral experiments to improve neutron propagation and gamma heating calculations

International Nuclear Information System (INIS)

Oceraies, Y.; Caumette, P.; Devillers, C.; Bussac, J.

1979-01-01

1) The studies to define and improve the accuracies of neutron propagation and gamma heating calculations from integral experiments are encompassed in the field of the fast reactor physics program at CEA. 2) A systematic analysis of neutron propagation in Fe-Na clean media, with variable volumic composition between 0 and 100% in sodium, has been performed on the HARMONIE source reactor. Gamma heating traverses in the core, the blankets and several control rods, have been measured in the R Z core program at MASURCA. The experimental techniques, the accuracies and the results obtained are given. The approximations of the calculational methods used to analyse these experiments and to predict the corresponding design parameters are also described. 3) Particular emphasis is given to the methods planned to improve fundamental data used in neutron propagation calculations, using the discrepancies observed between measured and calculated results in clean integral experiments. One of these approaches, similar to the techniques used in core physics, relies upon sensitivity studies and eventually on adjustment techniques applied to neutron propagation. (author)

Linking Quality Assurance to Performance Improvement to Produce a High Reliability Organization

International Nuclear Information System (INIS)

Silvey, Andrea B.; Warrick, Louise H.

2008-01-01

Three basic change management models are currently used in healthcare to produce and sustain quality improvement. We have presented the context to determine where any particular organization stands within these paradigms. We also have introduced a change-management tool used to assess, plan, and monitor leadership effort and commitment to quality improvement and culture change activities, tracked as 'momentum for change.' This 'momentum' is measured at eight discrete levels, from recognizing a performance gap to officially implementing changes intended to improve quality

Application of probabilistic event attribution in the summer heat extremes in the western US to emissions traced to major industrial carbon producers

Science.gov (United States)

Mera, R. J.; Allen, M. R.; Mote, P.; Ekwurzel, B.; Frumhoff, P. C.; Rupp, D. E.

2015-12-01

Heat waves in the western US have become progressively more severe due to increasing relative humidity and nighttime temperatures, increasing the health risks of vulnerable portions of the population, including Latino farmworkers in California's Central Valley and other socioeconomically disadvantaged communities. Recent research has shown greenhouse gas emissions doubled the risk of the hottest summer days during the 2000's in the Central Valley, increasing public health risks and costs, and raising the question of which parties are responsible for paying these costs. It has been argued that these costs should not be taken up solely by the general public through taxation, but that additional parties can be considered, including multinational corporations who have extracted and marketed a large proportion of carbon-based fuels. Here, we apply probabilistic event attribution (PEA) to assess the contribution of emissions traced to the world's 90 largest major industrial carbon producers to the severity and frequency of these extreme heat events. Our research uses very large ensembles of regional climate model simulations to calculate fractional attribution of policy-relevant extreme heat variables. We compare a full forcings world with observed greenhouse gases, sea surface temperatures and sea ice extent to a counter-factual world devoid of carbon pollution from major industrial carbon producers. The results show a discernable fraction of record-setting summer temperatures in the western US during the 2000's can be attributed to emissions sourced from major carbon producers.

Improving cancer treatment with cyclotron produced radionuclides

International Nuclear Information System (INIS)

Larson, S.M.; Finn, R.D.

1992-01-01

Our goal is to improve the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. The radiochemistry group seeks to develop innovative cyclotron targetry, radiopharmaceuticals, and radiolabeled antibodies, which are then used to assess important unanswered questions in tumor pharmacology and immunology. Examples include selected positron emitting radionuclides, such as Iodine-124, and Ga-66; I-124, I-123, I-131 labeled iododeoxyuridine, C-11 colchicine, and antimetabolites, like C-11 methotrexate; and radiolabeled antibodies, 3F8, M195, A33, and MRK16 for application in the pharmacology and immunology projects. The pharmacology program studies tumor resistance to chemotherapy, particularly the phenomenon of multidrug resistance and the relationship between tumor uptake and retention and the tumor response for anti-metabolite drugs. The immunology program studies the physiology of antibody localization at the tissue level as the basis for novel approaches to improving tumor localization such as through the use of an artificial lymphatic system which mechanically reduces intratumoral pressures in tumors in vivo. Quantitative imaging approaches based on PET and SPECT in radioimmunotherapy are studied to give greater insight into the physiology of tumor localization and dosimetry

Improved heat transfer on condensers with Ti tubes by means of granulate spheres

International Nuclear Information System (INIS)

Multer, I.

1985-01-01

Swedish power plants are located on the Baltic Sea coast and on the West coast. The cooling water is of high quality with low to medium impurity concentrations. In spite of this, pipe leakages occurred after a short period of operation, and the SoMs tubes had to be replaced by Ti tubes. Contrary to expectations, the heat transfer coefficient was higher by 10 to 20% with Ti tubes. This improvement is assumed to be due to the fact that Ti tube condensers are easier to clean by means of foamed rubber balls. As it was impossible to obtain a heat transfer coefficient of 100% with foamed rubber balls, experiments were carried out with granulate balls developed by Taprogge. In 6 series of experiments the overall heat transfer coefficient could be raised by 8%. Further experiments will follow. (orig.) [de

Transitions to improved core electron heat confinement in JT-II plasmas

International Nuclear Information System (INIS)

Estrada, T.; Medina, F.; Ascasibar, E.; Balbin, R.; Castejon, F.; Hidalgo, C.; Lopez-Bruna, D.; Petrov, S.

2008-01-01

Transitions to improved core electron heat confinement are triggered by low order rational magnetic surfaces in TJ-II ECH plasmas. Transitions triggered by the rational surface n=4/m=2 show an increase in the ion temperature synchronized with the increase in the electron temperature. SXR measurements demonstrate that, under certain circumstances, the rational surface positioned inside the plasma core region precedes and provides a trigger for the transition. (author)

Fast wave heating experiments in the ion cyclotron range of frequencies on ATF

Energy Technology Data Exchange (ETDEWEB)

Kwon, M; Shepard, T D; Goulding, R H [Oak Ridge National Lab., TN (United States); and others

1992-07-01

Fast wave heating experiments in the ion cyclotron range of frequencies (ICRF) were performed on target plasmas produced by 350 kW of electron cyclotron heating at 53 GHz and also by neutral beam injection in the Advanced Toroidal Facility (ATF). Various heating regimes were investigated in the frequency range between 9.2 MHz and 28.8 MHz with magnetic fields of 0.95 T and 1.9 T on axis. The nominal pulse lengths of up to 200 kW RF power were in the range between 100 and 400 ms. Data from spectroscopy, loading measurements, and edge RF and Langmuir probes were used to characterize the RF induced effects on the ATF plasma. In the hydrogen minority regime at low plasma density, large suprathermal ion tails were observed with a neutral particle analyser. At high density (n-bar{sub e} {>=} 5.0 x 10{sup 13} cm{sup -3}) substantial increases in antenna loading were observed, but ICRF power was insufficient to produce definitive heating results. A two-dimensional RF heating code, ORION, and a Fokker-Planck code, RFTRANS, were used to simulate these experiments. A simulation of future high power, higher density experiments in ATF indicates improved bulk heating results due to the improved loading and more efficient thermalization of the minority tail. (author). 29 refs, 16 figs, 3 tabs.

Enhanced performance on high current discharges in JET produced by ICRF heating during the current rise

International Nuclear Information System (INIS)

Bures, M.; Bhatnagar, V.; Cotrell, G.; Corti, S.; Christiansen, J.P.; Hellsten, T.; Jacquinot, J.; Lallia, P.; Lomas, P.; O'Rourke, J.; Taroni, A.; Tibone, F.; Start, D.F.H.

1989-01-01

The performance of high current discharges can be increased by applying central ICRF heating before or shortly after the onset of sawtooth activity in the plasma current rise phase. Sawtooth-free periods have been obtained resulting in the enhanced discharge performance. High T e (0) 9 - 10.5 keV with peaked profiles T e (0)/ e > = 3 - 4 were obtained giving values of n e (0)T e (0) up to 6x10 20 (keV m -3 ). Improvements in T i (0) and neutron production are observed. A 60 % enhancement in D-D reaction rate from 2nd harmonic deuterium (2ω CD ) heating appears to be present. In all current rise (CR) discharges radiation amounts to 25-50 % of total power. (author) 4 refs., 6 figs

Use of waste heat from a dairy for heating of a community house

Energy Technology Data Exchange (ETDEWEB)

Rehn, C

1976-01-01

In a dairy, a lot of cooling capacity is needed. This article describes how this waste heat can be used for heating a community house including a sport establishment and producing hot water for that house. Four different technical solutions are discussed; (1) floor heat, (2) heat transfer connected to the ventilation, (3) regenerative heat exchanger, and (4) use of heat pumps.

Direct currents produced by hf heating of plasma

International Nuclear Information System (INIS)

Klima, R.

1974-01-01

In addition to the well-known diffusion currents, toroidal direct currents arise in h.f. heated plasmas as a result of a momentum transfer from the h.f. field to plasma particles. The estimates of steady-state conditions are given for these currents. Particularly, the possibility of stationary operation of a Tokamak device is analyzed. (author)

Design and economic investigation of shell and tube heat exchangers using Improved Intelligent Tuned Harmony Search algorithm

Directory of Open Access Journals (Sweden)

Oguz Emrah Turgut

2014-12-01

Full Text Available This study explores the thermal design of shell and tube heat exchangers by using Improved Intelligent Tuned Harmony Search (I-ITHS algorithm. Intelligent Tuned Harmony Search (ITHS is an upgraded version of harmony search algorithm which has an advantage of deciding intensification and diversification processes by applying proper pitch adjusting strategy. In this study, we aim to improve the search capacity of ITHS algorithm by utilizing chaotic sequences instead of uniformly distributed random numbers and applying alternative search strategies inspired by Artificial Bee Colony algorithm and Opposition Based Learning on promising areas (best solutions. Design variables including baffle spacing, shell diameter, tube outer diameter and number of tube passes are used to minimize total cost of heat exchanger that incorporates capital investment and the sum of discounted annual energy expenditures related to pumping and heat exchanger area. Results show that I-ITHS can be utilized in optimizing shell and tube heat exchangers.

Cows exposed to heat stress during fetal life exhibit improved thermal tolerance.

Science.gov (United States)

Ahmed, B M S; Younas, U; Asar, T O; Dikmen, S; Hansen, P J; Dahl, G E

2017-08-01

Maternal heat stress during late gestation affects calf function during postnatal life. The objective of the present study was to evaluate whether calves that experience heat stress in utero have altered thermoregulatory responses to acute heat stress later in life. Specifically, the hypothesis was that heat stress in utero would improve the response to acute heat stress at maturity. Females were born to dams exposed to heat stress or cooled during late gestation preceding their birth. All animals were raised postnatally under identical management. Twelve lactating Holstein cows that were exposed to in utero heat stress (HT) and 12 that were exposed to in utero control (CON) were used. A heat stress challenge was conducted in 3 blocks using 4 HT and 4 CON cows matched according to milk yield, stage of lactation, and parity. Each challenge consisted of transfer from a barn with shade and evaporative cooling to one with shade but no additional cooling for 48 h. The challenge was replicated twice for each block. Sweating rate, respiration rate, rectal temperature (RT), and skin temperature were measured on each cow at 0900, 1100, 1300, 1500, and 1700 h for 2 consecutive days. Mean ambient temperature across 6 challenge days was 26.15 ± 4.75°C. Tendencies for differences at 1700 h were observed between treatments for RT (HT: 39.5 ± 0.1; CON: 39.6 ± 0.1°C; = 0.065), however, there was no difference in respiration rate (HT: 77.6 ± 1.6; CON: 79.5 ± 1.6 bpm; = 0.85). Sweating rate for shaved skin (HT: 29.4 ± 2.0; CON: 36.0 ± 2.0 g/mh; = 0.057) and for non-shaved skin (HT: 22.5 ± 1.5; CON: 29.2 ± 1.2 g/mh; = 0.01) differed between groups. However, there was no effect on skin temperature at the shaved location (HT: 36.2 ± 0.2; CON: 36.0 ± 0.2°C; = 0.81), but there was a tendency for differences for the non-shaved area (HT: 35.4 ± 0.2; CON: 34.9 ± 0.2°C; = 0.097). Cows that underwent in utero heat stress had greater skin temperature at 1700 h vs. in utero

Technical specification improvements to containment heat removal and emergency core cooling systems: Final report

International Nuclear Information System (INIS)

Sullivan, W.P.; Ha, C.; Pentzien, D.C.; Visweswaran, S.

1988-07-01

This report presents the results of an analysis for technical specification improvements to the emergency core cooling systems (ECCS) and containment heat removal systems (EPRI Research Project 2142-3). The objective of this project is to further develop a reliability- and risk-based methodology to provide improvements by considering groups of surveillance test intervals and allowed out-of-service times jointly. This was done for the technical specifications for the ECCS, containment heat removal equipment, and supporting systems of a boiling water reactor plant. The project (1) developed a methodology for optimizing groups of surveillance test intervals and allowed out-of-service times jointly, (2) applied the methodology in a case study of a specific operating plant, Hatch-2, and (3) evaluated benefits of the application. The results of the case study demonstrate that beneficial technical specification improvements can be realized with application of the methodology. By tightening a small group of sensitive surveillance test intervals (STIs) and allowed out-of-service times (AOTs), a larger group of less sensitive STIs and AOTs can be extended resulting in an overall plant operating cost improvement without reducing the plant safety. The reliability- and risk-based methodology and results from this project can be effectively applied for technical specification improvements at other operating plants

Evaluation of inductive heating energy of sub-size improved DPC-C conductor by calorimetric method

International Nuclear Information System (INIS)

Ito, Toshinobu; Koizumi, Norikiyo; Wakabayashi, Hiroshi; Miura, Yuushi; Fujisaki, Hiroshi; Matsui, Kunihiro; Takahashi, Yoshikazu; Tsuji, Hiroshi

1996-08-01

The improved DPC-U conductor consisting of 648 chrome plated NbTi strands was fabricated and its stability has been investigated using 1/24 sub-size conductor. In the stability experiment, the inductive heating method was applied to originate initial normal zone. Since it is difficult to calculate the inductive heating energy deposited on the conductor because of complicate geometry of the twisted multi-strand cable, inductive heating energy had to be experimentally evaluated using calorimetric method. The heating energy is in proportion to integration of square of an applied sinusoidal wave pulsed current over the heating period. The experimental result shows the proportional constants for the conductor and conduit are 2.062 x 10 -3 [J/A 2 s] and 0.771 x 10 -3 [J/A 2 s], respectively. The coupling between the eddy currents in the strands and conduit might take effect on the heating energy put in the strands. It was shown this effect was however small in this experiment. Consequently, the inductive heating energy applied in the strands was estimated to be the proportional constant of 1.291 x 10 -3 [J/A 2 s] from the difference of the heat energies in the conductor and conduit. (author)

Phase transformation based pyroelectric waste heat energy harvesting with improved practicality

International Nuclear Information System (INIS)

Jo, Hwan Ryul; Lynch, Christopher S

2016-01-01

In 2014, almost 60% of thermal energy produced in the United States was lost to the environment as waste heat. Ferroelectric based pyroelectric devices can be used to convert some of this waste heat into usable electrical energy using the Olsen cycle, an ideal thermodynamic cycle, but there are a number of barriers to its realization in a practical device. This study uses the Olsen cycle to benchmark a less efficient thermodynamic cycle that is more easily implemented in devices. The ferroelectric pyroelectric material used was (Pb 0.97 La 0.02 )(Zr 0.55 Sn 0.32 Ti 0.13 )O 3 ceramic, a ferroelectric material that undergoes a temperature driven phase transformation. A net energy density of 0.27 J cm −3 per cycle was obtained from the ferroelectric material using the modified cycle with a temperature change between 25°C and 180°C. This is 15.5% of the Olsen cycle result with the same temperature range and 1–8 MV m −1 applied electric field range. The power density was estimated to 13.5 mW cm −3 with given experimental conditions. A model is presented that quantitatively describes the effect of several parameters on output energy density and can be used to design ferroelectric based pyroelectric energy converters. The model indicates that optimization of material geometry and heating conditions can increase the output power by an order or magnitude. (paper)

Recent research and development of intermediate heat exchanger for VHTR plant

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Akira; Matsumura, Noboru; Nishikawa, Hidetsugu; Yamada, Seiya [Nagasaki Shipyard and Engine Works, Mitsubishi Heavy Industries, Ltd., Nagasaki (Japan)

1984-07-01

This paper describes recent tests which show progress in design of Intermediate Heat Exchanger (IHX) for high-temperature gas cooled reactor plants developed for process heat application utilizing nuclear thermal energy. As the IHX must have a large heat exchanging capacity, the most important consideration is to design a compact heat exchanger having high efficiency. For the improvement of heat transfer characteristics, tests were performed at Mitsubishi Heavy Industries such as, trial manufacturing, heat transfer characteristic tests and nondestructive inspection tests of finned tubes. Results are as follows; (1) Finned tubes produced by rolling were able to be wound helically by bending machine. (2) Laboratory tests showed this tube had good heat transfer characteristics. (3) There was not much difference between finned tubes and bare tubes for detection of defects by the eddy current tests. (4) A trial assembly using the same scale model showed that the present design is easy to assemble. (5) Automatic orbital welding can be adopted for the welding between tube and tube sheet. As the result of the experiences gained from these successful tests, the design of the IHX has been greatly improved. (author)

Fluid Analysis and Improved Structure of an ATEG Heat Exchanger Based on Computational Fluid Dynamics

Science.gov (United States)

Tang, Z. B.; Deng, Y. D.; Su, C. Q.; Yuan, X. H.

2015-06-01

In this study, a numerical model has been employed to analyze the internal flow field distribution in a heat exchanger applied for an automotive thermoelectric generator based on computational fluid dynamics. The model simulates the influence of factors relevant to the heat exchanger, including the automotive waste heat mass flow velocity, temperature, internal fins, and back pressure. The result is in good agreement with experimental test data. Sensitivity analysis of the inlet parameters shows that increase of the exhaust velocity, compared with the inlet temperature, makes little contribution (0.1 versus 0.19) to the heat transfer but results in a detrimental back pressure increase (0.69 versus 0.21). A configuration equipped with internal fins is proved to offer better thermal performance compared with that without fins. Finally, based on an attempt to improve the internal flow field, a more rational structure is obtained, offering a more homogeneous temperature distribution, higher average heat transfer coefficient, and lower back pressure.

Heat treated 9 Cr-1 Mo steel material for high temperature application

Science.gov (United States)

Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

2012-08-21

The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

Flexibility of Large-Scale Solar Heating Plant with Heat Pump and Thermal Energy Storage

DEFF Research Database (Denmark)

Luc, Katarzyna Marta; Heller, Alfred; Rode, Carsten

2017-01-01

to decrease biomass use in a district heating system. The paper focuses on the renewable energy-based district heating system in Marstal, Denmark, with heat produced in central solar heating plant, wood pellet boiler, heat pump and bio-oil boiler. The plant has been the object of research and developments...

A numerical study of vorticity-enhanced heat transfer

Science.gov (United States)

Wang, Xiaolin; Alben, Silas

2012-11-01

The Glezer lab at Georgia Tech has found that vorticity produced by vibrated reeds can improve heat transfer in electronic hardware. Vortices enhance forced convection by boundary layer separation and thermal mixing in the bulk flow. In this work, we simulate the heat transfer process in a 3-dimensional plate-fin heat sink. We propose a simplified model by considering flow and temperature in a 2-D channel, and extend the model to the third dimension using a 1-D heat fin model. We simulate periodically steady-state solutions. We determine how the global Nusselt number is increased, depending on the vortices' strengths and spacings, in the parameter space of Reynolds and Peclet numbers. We find a surprising spatial oscillation of the local Nusselt number due to the vortices. Support from NSF-DMS grant 1022619 is acknowledged.

Nuclear fuel assembly with improved spectral shift-producing rods

International Nuclear Information System (INIS)

Ferrari, H.M.

1987-01-01

This patent describes a nuclear reactor having fuel assemblies and a moderator-coolant liquid flowing through the fuel assemblies, each fuel assembly including an organized array of nuclear fuel rods wherein the moderator-coolant liquid flows along the fuel rods, at least one improved spectral shift-producing rod disposed among the fuel rods. The spectra shift-producing rod consists of: (a) an elongated hollow hermetically-sealed tubular member; (b) a weakened region formed in a portion of the member, the portion being subject to rupture at a given level of internal pressure; and (c) burnable poison material contained in the member which generates gas in the member as operation of the reactor proceeds normally, the material being soluble in the moderator-coolant liquid when brought into contact therewith; (d) the given level of internal pressure being less than the maximum level of internal pressure normally expected to be generated within the member by the poison material by normal operation of the reactor

Comparative Evaluation of Marginal Adaptation and Fracture Strength of Different Ceramic Inlays Produced by CEREC Omnicam and Heat-Pressed Technique

Directory of Open Access Journals (Sweden)

F. D. Oz

2018-01-01

Full Text Available Objective. The aim of this in vitro study was to evaluate marginal adaptation and fracture strength of inlays produced by CEREC Omnicam using different types of blocs and heat-pressed technique. Methods: Seventy-five extracted human mandibular molars were divided randomly into 5 groups (n=15. 60 molars in four groups received MOD inlay preparations. Experimental groups were CO: Intact teeth, EC: IPS e.max CAD and CEREC, LU: Lava Ultimate and CEREC, EL: IPS Empress CAD and CEREC, EP: IPS Empress Esthetic ingots and heat-pressed technique. Marginal gap measurements were taken with a stereomicroscope. Restorations were cemented with Variolink N and stored in distilled water at 37°C for 24 hours. All samples were subjected to thermocycling. The fracture strength of specimens was determined at a 0.5 mm/min crosshead speed until fracture. Fracture modes were determined. Statistical analyses were performed using one-way analysis of variance for fracture strength data and Kruskal–Wallis for marginal gap data (p=0.05. Results. The mean marginal gap size of EC, LU, EL, and EP were 33.54 µm, 33.77 µm, 34.23 µm, and 85.34 µm, respectively. EP had statistically higher values than other groups. The fracture strength values were significantly higher in the intact teeth group (3959,00 ± 1279,79 N than those of restored groups EC (2408,00 ± 607,97 N, LU (2206,73 ± 675,16, EL (2573.27 ± 644,73 ve EP (2879,53 ± 897,30. Conclusion. Inlays fabricated using CEREC Omnicam demonstrated better marginal adaptation than inlays produced with heat-pressed technique, whereas fracture strength values of inlays fabricated with different type of blocks using CEREC Omnicam exhibited similarity to those fabricated with heat-pressed technique.

Comparative Evaluation of Marginal Adaptation and Fracture Strength of Different Ceramic Inlays Produced by CEREC Omnicam and Heat-Pressed Technique.

Science.gov (United States)

Oz, F D; Bolay, S

2018-01-01

The aim of this in vitro study was to evaluate marginal adaptation and fracture strength of inlays produced by CEREC Omnicam using different types of blocs and heat-pressed technique. Methods: Seventy-five extracted human mandibular molars were divided randomly into 5 groups ( n =15). 60 molars in four groups received MOD inlay preparations. Experimental groups were CO: Intact teeth, EC: IPS e.max CAD and CEREC, LU: Lava Ultimate and CEREC, EL: IPS Empress CAD and CEREC, EP: IPS Empress Esthetic ingots and heat-pressed technique. Marginal gap measurements were taken with a stereomicroscope. Restorations were cemented with Variolink N and stored in distilled water at 37°C for 24 hours. All samples were subjected to thermocycling. The fracture strength of specimens was determined at a 0.5 mm/min crosshead speed until fracture. Fracture modes were determined. Statistical analyses were performed using one-way analysis of variance for fracture strength data and Kruskal-Wallis for marginal gap data ( p =0.05). The mean marginal gap size of EC, LU, EL, and EP were 33.54  µ m, 33.77  µ m, 34.23  µ m, and 85.34  µ m, respectively. EP had statistically higher values than other groups. The fracture strength values were significantly higher in the intact teeth group (3959,00 ± 1279,79 N) than those of restored groups EC (2408,00 ± 607,97 N), LU (2206,73 ± 675,16), EL (2573.27 ± 644,73) ve EP (2879,53 ± 897,30). Inlays fabricated using CEREC Omnicam demonstrated better marginal adaptation than inlays produced with heat-pressed technique, whereas fracture strength values of inlays fabricated with different type of blocks using CEREC Omnicam exhibited similarity to those fabricated with heat-pressed technique.

Improved HYLIFE-II heat transport system and steam power plant: Impact on performance and cost of electricity

International Nuclear Information System (INIS)

Hoffman, M.A.; Lee, Ying T.

1992-12-01

The HYLIFE-II conceptual design has evolved and improved continually over the past four years to its present form. This paper describes the latest FY92 versions, Reference Case H1 (nominally 1 GWe net output) and the Enhanced Case HE (nominally 2 GWe net output), which take advantage of improvements in the tritium management system to eliminate the intermediate loop and the intermediate heat exchangers (IHX's). The improvements in the heat transport system and the steam power plant are described and the resulting cost reductions are evaluated. The new estimated cost of electricity (in 1990 dollars) is 6.6 cents/kWh for Reference Case H1 and 4.7 cents/kWh for the Enhanced Case

An investigation of heat transfer between a microcantilever and a substrate for improved thermal topography imaging

International Nuclear Information System (INIS)

Somnath, Suhas; King, William P

2014-01-01

This paper reports the numerical and experimental investigation of heat transfer from a heated microcantilever to a substrate and uses the resulting insights to improve thermal topography imaging. The cantilever sensitivity, defined as change in thermal signal due to changes in the topography height, is relatively constant for feature heights in the range 100–350 nm. Since the cantilever-substrate heat transfer is governed by thermal conduction through the air, the cantilever sensitivity is nearly constant across substrates of varying thermal conductivity. Surface features with lateral size larger than 2.5 μm can induce artifacts in the cantilever signal resulting in measurement errors as large as 28%. These artifacts arise from thermal conduction from the cantilever in the lateral direction, parallel to the surface. We show how these artifacts can be removed by accounting for this lateral conduction and removing it from the thermal signal. This technique reduces the measurement error by as much as 26%, can be applied to arbitrary substrate topographies, and can be scaled to arrays of heated cantilevers. These results could lead to improvements in nanometer-scale thermal measurements including scanning thermal microscopy and tip-based nanofabrication. (paper)

Measurement improvements of heat flux probes for internal combustion engine; Nainen kikan ni okeru netsuryusokukei no kaihatsu to kento

Energy Technology Data Exchange (ETDEWEB)

Tajima, H; Tasaka, H [Miyazaki University, Miyazaki (Japan)

1997-10-01

In heat flux measurement in engines, material properties of a heat flux probe and numerical prediction of those influence have been discussed rather than practical measurement accuracy. This study featured the process for the quantitative examination of heat flux probes. Although the process required direct comparison among all the probes and additional measurements in a constant volume bomb, precision of heat flux measurement was greatly improved so that the essential characteristics of heat transfer in engines can be detected. 9 refs., 8 figs., 1 tab.

Microbiota-Produced Succinate Improves Glucose Homeostasis via Intestinal Gluconeogenesis

DEFF Research Database (Denmark)

De Vadder, Filipe; Kovatcheva-Datchary, Petia; Zitoun, Carine

2016-01-01

Beneficial effects of dietary fiber on glucose and energy homeostasis have long been described, focusing mostly on the production of short-chain fatty acids by the gut commensal bacteria. However, bacterial fermentation of dietary fiber also produces large amounts of succinate and, to date......, no study has focused on the role of succinate on host metabolism. Here, we fed mice a fiber-rich diet and found that succinate was the most abundant carboxylic acid in the cecum. Dietary succinate was identified as a substrate for intestinal gluconeogenesis (IGN), a process that improves glucose...

Improvement of the decay heat removal characteristics of the generation IV gas-cooled fast reactor

International Nuclear Information System (INIS)

Epiney, A.S.

2010-01-01

Gas cooling in nuclear power plants (NPPs) has a long history, the corresponding reactor types developed in France, the UK and the US having been thermal neutron spectrum systems using graphite as the moderator. The majority of NPPs worldwide, however, are currently light water reactors, using ordinary water as both coolant and moderator. These NPPs - of the so-called second generation - will soon need replacement, and a third generation is now being made available, offering increased safety while still based on light water technology. For the longer-term future, viz. beyond the year 2030, R and D is currently ongoing on Generation IV NPPs, aimed at achieving closure of the nuclear fuel cycle, and hence both drastically improved utilization of fuel resources and minimization of long-lived radioactive wastes. Like the SFR, the GFR is an efficient breeder, also able to work as iso-breeder using simply natural uranium as feed and producing waste which is predominantly in the form of fission products. The main drawback of the GFR is the difficulty to evacuate decay heat following a loss-of-coolant accident (LOCA) due to the low thermal inertia of the core, as well as to the low coolant density. The present doctoral research focuses on the improvement of decay heat removal (DHR) for the Generation-IV GFR. The reference GFR system design considered in the thesis is the 2006 CEA concept, with a power of 2400 MWth. The CEA 2006 DHR strategy foresees, in all accidental cases (independent of the system pressure), that the reactor is shut down. For high pressure events, dedicated DHR loops with blowers and heat exchangers are designed to operate when the power conversion system cannot be used to provide acceptable core temperatures under natural convection conditions. For de-pressurized events, the strategy relies on a dedicated small containment (called the guard containment) providing an intermediate back-up pressure. The DHR blowers, designed to work under these pressure

Improvement of the decay heat removal characteristics of the generation IV gas-cooled fast reactor

International Nuclear Information System (INIS)

Epiney, A. S.

2010-09-01

The majority of NPPs worldwide are currently light water reactors, using ordinary water as both coolant and moderator. (...) For the longer-term future, viz. beyond the year 2030, Research and Development is currently ongoing on Generation IV NPPs, aimed at achieving closure of the nuclear fuel cycle, and hence both drastically improved utilization of fuel resources and minimization of long-lived radioactive wastes. Since the very beginning of the international cooperation on Generation IV, viz. the year 2000, the main research interest in Europe as regards the advanced fast-spectrum systems needed for achieving complete fuel cycle closure, has been for the Sodium-cooled Fast Reactor (SFR). However, the Gas-cooled Fast Reactor (GFR) is currently considered as the main back-up solution. Like the SFR, the GFR is an efficient breeder, also able to work as iso-breeder using simply natural uranium as feed and producing waste which is predominantly in the form of fission products. The main drawback of the GFR is the difficulty to evacuate decay heat following a loss-of-coolant accident (LOCA) due to the low thermal inertia of the core, as well as to the low coolant density. The present doctoral research focuses on the improvement of decay heat removal (DHR) for the Generation-IV GFR. The reference GFR system design considered in the thesis is the 2006 CEA concept, with a power of 2400 MWth. The CEA 2006 DHR strategy foresees, in all accidental cases (independent of the system pressure), that the reactor is shut down. For high pressure events, dedicated DHR loops with blowers and heat exchangers are designed to operate when the power conversion system cannot be used to provide acceptable core temperatures under natural convection conditions. For depressurized events, the strategy relies on a dedicated small containment (called the guard containment) providing an intermediate back-up pressure. The DHR blowers, designed to work under these pressure conditions, need to be

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 ...

Modeling of heat transfer into a heat pipe for a localized heat input zone

International Nuclear Information System (INIS)

Rosenfeld, J.H.

1987-01-01

A general model is presented for heat transfer into a heat pipe using a localized heat input. Conduction in the wall of the heat pipe and boiling in the interior structure are treated simultaneously. The model is derived from circumferential heat transfer in a cylindrical heat pipe evaporator and for radial heat transfer in a circular disk with boiling from the interior surface. A comparison is made with data for a localized heat input zone. Agreement between the theory and the model is good. This model can be used for design purposes if a boiling correlation is available. The model can be extended to provide improved predictions of heat pipe performance

Heat storage in forest biomass significantly improves energy balance closure particularly during stable conditions

Science.gov (United States)

Lindroth, A.; Mölder, M.; Lagergren, F.

2009-08-01

Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation nearly perfectly. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy

Modeling and Control of Heat Networks with Storage : the Single-Producer Multiple-Consumer Case

NARCIS (Netherlands)

Scholten, Tjeert Wobko; De Persis, Claudio; Tesi, Pietro

2015-01-01

In heat networks, energy storage is a viable approach to balance demand and supply. In such a network, a heat carrier is used in the form of water, where heat is injected and extracted through heat exchangers. The network can transport and store heated water in stratification tanks to shift loads in

Modeling and control of heat networks with storage: The single-producer multiple-consumer case.

NARCIS (Netherlands)

Scholten, Tjardo; De Persis, Claudio; Tesi, Pietro

2015-01-01

In heat networks, energy storage is a viable approach to balance demand and supply. In such a network, a heat carrier is used in the form of water, where heat is injected and extracted through heat exchangers. The network can transport and store heated water in stratification tanks to shift loads in

Improved Design Concept for ensuring the Passive Decay Heat Removal Performance of an SFR

International Nuclear Information System (INIS)

Eoh, Jae Hyuk; Lee, Tae Ho; Han, Ji Woong; Kim, Seong O

2011-01-01

In order to enhance the operational reliability of a purely passive decay heat removal system in KALIMER, which is named as PDRC, three design options to prevent a sodium freezing in an intermediate decay heat removal circuit were proposed, and their feasibilities was quantitatively evaluated. For all the options, more specific design considerations were made to confirm their feasibility to properly materialize their concepts in a practical system design procedure, and the general definitions for a purely passive concept and its design features have been discussed. A numerical study to evaluate the coastdown flow effect of the primary pump was performed to figure out the early stage DHR capability inside reactor pool during a loss of normal heat sink accident. The thermal-hydraulic calculations have been made by using the COMMIX-1AR/P code, and it was found that the initiation of heat removal by DHX could be accelerated by the increase of the coastdown time but it needs a large-sized flywheel. For the demonstration of the innovative concept, a large scale sodium thermal-hydraulic test facility is currently being designed. It is very difficult to reproduce both a hydrodynamic and a thermodynamic similarity to the prototype plant if the thermal driving head is determined by structure-to-fluid heat transfer under natural circulation flow. Hence the similitude requirements for the sodium thermal-hydraulic test facility employing natural convection heat transfer were developed, and the preliminary design data of the test facility by implementing proper scaling methodologies was produced. The design restrictions imposed on the test facility and the scaling distortions of the design data to the full-scale system were also discussed

Heated humidification improves clinical outcomes, compared to a heat and moisture exchanger in children with tracheostomies.

Science.gov (United States)

McNamara, David G; Asher, M Innes; Rubin, Bruce K; Stewart, Alistair; Byrnes, Catherine A

2014-01-01

The upper airway humidifies and warms inspired gases before they reach the trachea, a process bypassed by the insertion of a tracheostomy, necessitating humidification of inspired gases. The optimal method of humidification is not known. We conducted a short-term 20-hour study and a long-term 10-week randomized crossover study comparing a heated humidifier (HH) to a heat and moisture exchanger (HME) in children with established tracheostomies. Subjects were assessed for clinical events, clinical examination findings, airway cytokine levels, and airway secretion viscoelasticity. For the short-term study, 15 children were recruited; for the long-term study, 14 children were recruited. Children using the HH had decreased respiratory examination score (P < .001) but no change in clinical events over the short term. There was a decrease in acute clinical events (P = .008) in the long-term study. No differences were found in airway secretion viscoelasticity results or cytokine levels in either study, but these sample numbers were limited. Over 20 hours use, HH, compared to HME, improved work of breathing. Over a longer 10 week treatment period HH resulted in decreased adverse clinical events.

Heat cascading regenerative sorption heat pump

Science.gov (United States)

Jones, Jack A. (Inventor)

1995-01-01

A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

Acoustic heating produced in the thermoviscous flow of a Bingham plastic

Science.gov (United States)

Perelomova, Anna

2011-02-01

This study is devoted to the instantaneous acoustic heating of a Bingham plastic. The model of the Bingham plastic's viscous stress tensor includes the yield stress along with the shear viscosity, which differentiates a Bingham plastic from a viscous Newtonian fluid. A special linear combination of the conservation equations in differential form makes it possible to reduce all acoustic terms in the linear part of of the final equation governing acoustic heating, and to retain those belonging to the thermal mode. The nonlinear terms of the final equation are a result of interaction between sounds and the thermal mode. In the field of intense sound, the resulting nonlinear acoustic terms form a driving force for the heating. The final governing dynamic equation of the thermal mode is valid in a weakly nonlinear flow. It is instantaneous, and does not imply that sounds be periodic. The equations governing the dynamics of both sounds and the thermal mode depend on sign of the shear rate. An example of the propagation of a bipolar initially acoustic pulse and the evolution of the heating induced by it is illustrated and discussed.

Heat from renewable energy. Comparison of heating systems and fuels concerning environmental aspects; Waerme aus regenerativen Energien. Heizungssysteme und Brennstoffe im oekologischen Vergleich

Energy Technology Data Exchange (ETDEWEB)

Weinberg, Jana; Stegelmeier, Marina; Kaltschmitt, Martin [TU Hamburg-Harburg (Germany). Inst. fuer Umwelttechnik und Energiewirtschaft

2013-02-01

So far, residential buildings in Germany are mainly heated with fossil fuels like heating oil and natural gas. Those fuels are burned in more or less efficient conversion plants and in doing so produce besides noteworthy amounts of greenhouse gas emissions also nitrogen oxides and particulate matter. Those emissions are not being tolerated any longer with society growing more and more environmentally-conscious. Consequently more environmentally friendly alternatives of supplying heat for residential buildings are in public discussion. For instance this is true for the use of geothermal energy, renewable fuels like biogas or wood and solar energy. Further improvement in the standard on thermal insulation of buildings to lower the absolute heating demand is discussed in parallel. To be able to evaluate these different possibilities concerning selected environmental impacts, the following work focuses on such heating options by means of life-cycle analysis. (orig.)

Heat-Treated TiO2 Plasma Spray Deposition for Bioactivity Improvement in Ti-6Al-4V Alloy

Science.gov (United States)

Kumari, Renu; Majumdar, Jyotsna Dutta

2017-12-01

In the present study, titanium di-oxide (TiO2) coating has been developed on Ti-6Al-4V substrate by plasma spray deposition. Followed by plasma spraying, heat treatment of the sprayed sample has been carried out by isothermally holding it at 823 K (550 °C) for 2 h. Microstructural analysis shows the presence of porosity and unmelted particles on the as-sprayed surface, the area fraction of which reduces after heat treatment. X-ray diffraction analysis shows the phase transformation from anatase (in precursor powder) to rutile (in as-sprayed coating and the same after heat treatment). There is an improvement in nano-hardness, "Young's modulus" and wear resistance in plasma-sprayed TiO2 coating (as-sprayed as well as post-heat-treated condition) as compared to as-received Ti-6Al-4V, though post-heat treatment offers a superior hardness, "young's modulus" and wear resistance as compared to as-sprayed coating. The corrosion behavior in "hank's solution" shows decrease in corrosion resistance after plasma spraying and post-heat treatment as compared to as-received substrate. A significant decrease in contact angle and improvement in bioactivity (in terms of apatite deposition) were observed in TiO2-coated surface as compared to as-received Ti-6Al-4V.

Method and Apparatus for the Portable Identification of Material Thickness and Defects Using Spatially Controlled Heat Application

Science.gov (United States)

Cramer, K. Elliott (Inventor); Winfree, William P. (Inventor)

1999-01-01

A method and a portable apparatus for the nondestructive identification of defects in structures. The apparatus comprises a heat source and a thermal imager that move at a constant speed past a test surface of a structure. The thermal imager is off set at a predetermined distance from the heat source. The heat source induces a constant surface temperature. The imager follows the heat source and produces a video image of the thermal characteristics of the test surface. Material defects produce deviations from the constant surface temperature that move at the inverse of the constant speed. Thermal noise produces deviations that move at random speed. Computer averaging of the digitized thermal image data with respect to the constant speed minimizes noise and improves the signal of valid defects. The motion of thermographic equipment coupled with the high signal to noise ratio render it suitable for portable, on site analysis.

Simulation of nonlinear dynamics of a PWR core by an improved lumped formulation for fuel heat transfer

International Nuclear Information System (INIS)

Su, Jian; Cotta, Renato M.

2000-01-01

In this work, thermohydraulic behaviour of PWR, during reactivity insertion and partial loss-of-flow, is simulated by using a simplified mathematical model of reactor core and primary coolant. An improved lumped parameter formulation for transient heat conduction in fuel rod is used for core heat transfer modelling. Transient temperature response of fuel, cladding and coolant is analysed. (author)

Renewable-based heat supply of multi-apartment buildings with varied heat demands

International Nuclear Information System (INIS)

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

2015-01-01

This study investigates the cost and primary energy use to heat an existing multi-apartment building in Sweden, before and after deep energy efficiency renovation, with different types of renewable-based systems. District heating systems of different scales as well as local heat production based on bioelectric boilers, ground-source bioelectric heat pumps and wood pellet boilers with or without solar heating are considered. The annual energy demand of the building, calculated hour by hour, with and without energy efficiency improvements, are matched against the renewable-based heat supply options by techno-economic modeling to minimize cost for each considered heat supply option. The results show that the availability of heating technologies at the building site and the scale of the building's heat demand influence the cost and the primary energy efficiency of the heating options. District heat from large-scale systems is cost efficient for the building without energy-efficiency improvement, whereas electric heat pumps and wood pellet boilers are more cost efficient when implementing energy-efficiency improvement. However, the cost difference is small between these alternatives and sensitive to the size of building. Large-scale district heating with cogeneration of power is most primary energy efficient while heat pumps and medium-scale district heating are nearly as efficient. - Highlights: • Heating technologies influence costs and primary energy use of a building. • Large-scale district heating with cogeneration of power is primary energy efficient. • Large-scale district heating is cost efficient for buildings with large heat demand. • Heat pumps and pellet boilers are cost competitive in energy-efficient buildings.

Using geothermal energy to heat a portion of a formation for an in situ heat treatment process

Science.gov (United States)

Pieterson, Roelof; Boyles, Joseph Michael; Diebold, Peter Ulrich

2010-06-08

Methods of using geothermal energy to treat subsurface formations are described herein. Methods for using geothermal energy to treat a subsurface treatment area containing or proximate to hydrocarbons may include producing geothermally heated fluid from at least one subsurface region. Heat from at least a portion of the geothermally heated fluid may be transferred to the subsurface treatment area to heat the subsurface treatment area. At least some hydrocarbon fluids may be produced from the formation.

Improved dental implant drill durability and performance using heat and wear resistant protective coatings.

Science.gov (United States)

Er, Nilay; Alkan, Alper; İlday, Serim; Bengu, Erman

2018-03-02

Dental implant drilling procedure is an essential step for implant surgery and frictional heat appeared in bone during drilling is a key factor affecting the success of an implant. The aim of this study is to increase the dental implant drill lifetime and performance using heat- and wear-resistant protective coatings hence to decrease the alveolar bone temperature caused by the dental implant drilling procedure. Commercially obtained stainless steel drills were coated with titanium aluminum nitride, diamond-like carbon, titanium boron nitride, and boron nitride coatings via magnetron-sputter deposition. Drilling procedure was performed on a bovine femoral cortical bone under the conditions mimicking clinical practice, where the tests were performed both under water-assisted cooling and under the conditions without any cooling was applied. Coated drill performances and durabilities were compared to that of three commonly used commercial drills which surfaces are made from namely; zirconia, black diamond and stainless steel. Protective coatings with boron nitride, titanium boron nitride and diamond-like carbon have significantly improved drill performance and durability. Especially boron nitride-coated drills have performed within safe bone temperature limits for 50 drillings even without any cooling is applied. Titanium aluminium nitride coated drills did not show any improvement over commercially obtained stainless steel drills. Surface modification using heat and wear resistant coatings is an easy and highly effective way to improve implant drill performance and durability, which can reflect positively on surgical procedure and healing period afterwards. The noteworthy success of different types of coatings is novel and likely to be applicable to various other medical systems.

Using microwave heating to improve the desorption efficiency of high molecular weight VOC from beaded activated carbon.

Science.gov (United States)

Fayaz, Mohammadreza; Shariaty, Pooya; Atkinson, John D; Hashisho, Zaher; Phillips, John H; Anderson, James E; Nichols, Mark

2015-04-07

Incomplete regeneration of activated carbon loaded with organic compounds results in heel build-up that reduces the useful life of the adsorbent. In this study, microwave heating was tested as a regeneration method for beaded activated carbon (BAC) loaded with n-dodecane, a high molecular weight volatile organic compound. Energy consumption and desorption efficiency for microwave-heating regeneration were compared with conductive-heating regeneration. The minimum energy needed to completely regenerate the adsorbent (100% desorption efficiency) using microwave regeneration was 6% of that needed with conductive heating regeneration, owing to more rapid heating rates and lower heat loss. Analyses of adsorbent pore size distribution and surface chemistry confirmed that neither heating method altered the physical/chemical properties of the BAC. Additionally, gas chromatography (with flame ionization detector) confirmed that neither regeneration method detectably altered the adsorbate composition during desorption. By demonstrating improvements in energy consumption and desorption efficiency and showing stable adsorbate and adsorbent properties, this paper suggests that microwave heating is an attractive method for activated carbon regeneration particularly when high-affinity VOC adsorbates are present.

CAD/CAM produces dentures with improved fit.

Science.gov (United States)

Steinmassl, Otto; Dumfahrt, Herbert; Grunert, Ingrid; Steinmassl, Patricia-Anca

2018-02-22

Resin polymerisation shrinkage reduces the congruence of the denture base with denture-bearing tissues and thereby decreases the retention of conventionally fabricated dentures. CAD/CAM denture manufacturing is a subtractive process, and polymerisation shrinkage is not an issue anymore. Therefore, CAD/CAM dentures are assumed to show a higher denture base congruence than conventionally fabricated dentures. It has been the aim of this study to test this hypothesis. CAD/CAM dentures provided by four different manufacturers (AvaDent, Merz Dental, Whole You, Wieland/Ivoclar) were generated from ten different master casts. Ten conventional dentures (pack and press, long-term heat polymerisation) made from the same master casts served as control group. The master casts and all denture bases were scanned and matched digitally. The absolute incongruences were measured using a 2-mm mesh. Conventionally fabricated dentures showed a mean deviation of 0.105 mm, SD = 0.019 from the master cast. All CAD/CAM dentures showed lower mean incongruences. From all CAD/CAM dentures, AvaDent Digital Dentures showed the highest congruence with the master cast surface with a mean deviation of 0.058 mm, SD = 0.005. Wieland Digital Dentures showed a mean deviation of 0.068 mm, SD = 0.005, Whole You Nexteeth prostheses showed a mean deviation of 0.074 mm, SD = 0.011 and Baltic Denture System prostheses showed a mean deviation of 0.086 mm, SD = 0.012. CAD/CAM produces dentures with better fit than conventional dentures. The present study explains the clinically observed enhanced retention and lower traumatic ulcer-frequency in CAD/CAM dentures.

Heat-resistant, extended-spectrum β-lactamase-producing Klebsiella pneumoniae in endoscope-mediated outbreak

DEFF Research Database (Denmark)

Jørgensen, S.B.; Bojer, Martin Saxtorph; Boll, E.J.

2016-01-01

disinfection in a decontaminator designated for such use. The genetic marker clpK, which increases microbial heat resistance, has previously been described in K. pneumoniae outbreak strains. Aim To investigate the role of clpK in biofilm formation and heat-shock stability in the outbreak strain. Methods...... construction and heat-shock assays. Findings Five patients and one intubation endoscope contained K. pneumoniae with the same amplified fragment length polymorphism pattern. The outbreak strain contained the clpK genetic marker, which rendered the strain its increased heat resistance. The survival rate....... Heat resistance of certain K. pneumoniae strains may facilitate survival in biofilms on medical equipment and hence increase the potential of those strains to persist and disperse in the hospital environment....

Living in cold homes after heating improvements: Evidence from Warm-Front, England's Home Energy Efficiency Scheme

International Nuclear Information System (INIS)

Critchley, Roger; Gilbertson, Jan; Grimsley, Michael; Green, Geoff

2007-01-01

Objective: To investigate explanatory factors for persistent cold temperatures in homes which have received heating improvements. Design: Analysis of data from a national survey of dwellings and households (in England occupied by low-income residents) that had received heating improvements or repairs under the Warm Front Scheme. Methods: Over the winters of 2001-02 and 2002-03, householders recorded living room and main bedroom temperatures in a diary. Entries were examined for 888 households, which had received high level heating interventions. Two hundred and twenty-two households were identified as occupying cold homes, with mean bedroom temperature below 16 deg. C or mean living room temperatures below 18 deg. C. Binary logistic regression was used to model dwelling and household features and then occupants' behaviour and attitudes in the 'cold homes' sub-set compared with the remainder of the high intervention group. Seventy-nine supplementary, structured telephone interviews explored reasons given for lower temperatures. Using graphical and tabular methods, householders preferring cooler homes were distinguished from those who felt constrained in some way. Results: Cold homes predominate in pre-1930 properties where the householder remains dissatisfied with the heating system despite major improvements funded by Warm Front. Residents of cold homes are less likely to have long-standing illness or disability, but more likely to experience anxiety or depression. A small sample of telephone interviews reveals those preferring lower temperatures for health or other reasons, report less anxiety and depression than those with limited control over their home environment. Their 'thermal resistance' to higher temperatures challenges orthodox definitions of comfort and fuel poverty

Various methods to improve heat transfer in exchangers

Directory of Open Access Journals (Sweden)

Pavel Zitek

2015-01-01

Full Text Available The University of West Bohemia in Pilsen (Department of Power System Engineering is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors. For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production. In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective.

Science.gov (United States)

Gao, C; Kuklane, K; Wang, F; Holmér, I

2012-12-01

The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home. © 2012 John Wiley & Sons A/S.

Development of a nonazeotropic heat pump for crew hygiene water heating

Science.gov (United States)

Walker, David H.; Deming, Glenn I.

1991-01-01

A heat pump system is currently under development to produce hot water for crew hygiene on future manned space missions. The heat pump uses waste heat sources and a nonazeotropic working fluid in a highly efficient cycle. The potential benefits include a reduction in peak power draw from 2 to 5 kW for electric cartridge heaters to just more than 100 W for the heat pump. As part of the heat pump development project, a unique high efficiency compressor was developed to maintain lubrication in a zero-gravity environment.

Mapping of potential heat sources for heat pumps for district heating in Denmark

International Nuclear Information System (INIS)

Lund, Rasmus; Persson, Urban

2016-01-01

The ambitious policy in Denmark on having a 100% renewable energy supply in 2050 requires radical changes to the energy systems to avoid an extensive and unsustainable use of biomass resources. Currently, wind power is being expanded and the increasing supply of electricity is slowly pushing the CHP (combined heat and power) plants out of operation, reducing the energy efficiency of the DH (district heating) supply. Here, large heat pumps for district heating is a frequently mentioned solution as a flexible demand for electricity and an energy efficient heat producer. The idea is to make heat pump use a low temperature waste or ambient heat source, but it has so far been very unclear which heat sources are actually available for this purpose. In this study eight categories of heat sources are analysed for the case of Denmark and included in a detailed spatial analysis where the identified heat sources are put in relation to the district heating areas and the corresponding demands. The analysis shows that potential heat sources are present near almost all district heating areas and that sea water most likely will have to play a substantial role as a heat source in future energy systems in Denmark. - Highlights: • The availability of heat sources for heat pumps in Denmark are mapped and quantified. • A novel methodology for assessment of low temperature industrial excess heat is presented. • There are heat sources available for 99% of district heating networks in Denmark. • The concentration of heat sources is generally bigger around bigger cities than smaller. • Ambient temperature heat sources will be more needed in district heating of big cities.

Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

KAUST Repository

Nouh, Mostafa A.; Arafa, Nadim M.; Abdel-Rahman, Ehab

2014-01-01

A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack's position, length and plate spacing are the three main parameters that have been investigated in this study. Stack's position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine's most powerful operating point.

Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

KAUST Repository

Nouh, Mostafa A.

2014-01-01

A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack\\'s position, length and plate spacing are the three main parameters that have been investigated in this study. Stack\\'s position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine\\'s most powerful operating point.

Economic and safety aspects of using moderator heat for feed water heating in a nuclear power plant

International Nuclear Information System (INIS)

Patwegar, I.A.; Dutta, Anu; Chaki, S.K.; Venkat Raj, V.

2002-01-01

Full text: In the proposed advanced heavy water reactor (AHWR), coolant and moderator are separated by the coolant channel. The coolant absorbs most of the fission heat produced in the reactor core. However, the moderator absorbs about 5 to 6 % of the fission heat. In a reactor producing 750 MW(th) power, this moderator heat is about 40 MW. In the present Indian PHWR (pressurized heavy water reactor) systems, this moderator heat is lost to a sink through the moderator heat exchangers, which are cooled by process water. This paper presents the results of the steam cycle analysis carried out for AHWR using moderator heat exchangers as part of the feed heating system. The present study is an attempt to determine the gain in electrical output (MW) if moderator heat is utilized for feed water heating. The operational and safety aspects of using moderator heat are also discussed in the paper

Efficiency improvement of a concentrated solar receiver for water heating system using porous medium

Science.gov (United States)

Prasartkaew, Boonrit

2018-01-01

This experimental study aims at investigating on the performance of a high temperature solar water heating system. To approach the high temperature, a porous-medium concentrated solar collector equipped with a focused solar heliostat were proposed. The proposed system comprised of two parts: a 0.7x0.7-m2 porous medium receiver, was installed on a 3-m tower, and a focused multi-flat-mirror solar heliostat with 25-m2 aperture area. The porous medium used in this study was the metal swarf or metal waste from lathing process. To know how the system efficiency could be improved by using such porous medium, the proposed system with- and without-porous medium were tested and the comparative study was performed. The experimental results show that, using porous medium for enhancing the heat transfer mechanism, the system thermal efficiency was increased about 25%. It can be concluded that the efficiency of the proposed system can be substantially improved by using the porous medium.

Differences of hormones involved in adipose metabolism and lactation between high and low producing Holstein cows during heat stress

Directory of Open Access Journals (Sweden)

Mingzi Qu

2015-12-01

Full Text Available The experiment was conducted to evaluate hormonal involvement in the adipose metabolism and lactation between high and low producing dairy cows in a hot environment. Forty Holstein healthy cows with a similar parity were used and assigned into high producing group (average production 41.44 ± 2.25 kg/d and low producing group (average production 29.92 ± 1.02 kg/d with 20 cows in each group. Blood samples were collected from caudal vein to determine the difference of hormones related to adipose metabolism and lactation. The highest, lowest, and average temperature humidity index (THI, recorded as 84.02, 79.35 and 81.89, respectively, indicated that cows were at the state of high heat stress. No significant differences between high and low producing groups were observed in the levels of nonestesterified fatty acid (NEFA, β-hydroxybutyrate (β-OHB, total cholesterol (TCHO, and insulin (INS (P > 0.05. However, the very low density lipoprotein (VLDL, apolipoprotein B100 (apoB-100, high-density lipoprotein (HDL-C and estrogen (E2 concentrations in high producing group were significantly higher than those of low producing group (P  0.05, whereas high producing group had a rise in the insulin-like growth factor-1 (IGF-1 level compared with low producing group (P < 0.05. These results indicated that, during summer, high and low producing dairy cows have similar levels of lipid catabolism, but high producing dairy cows have advantages in outputting hepatic triglyceride (TG.

Seasonal heat stress: Clinical implications and hormone treatments for the fertility of dairy cows.

Science.gov (United States)

De Rensis, F; Garcia-Ispierto, I; López-Gatius, F

2015-09-15

Heat stress has consequences on both the physiology and reproductive performance of cows, but the most dramatic effect for dairy producers is the decrease produced in fertility. The effects of heat stress on fertility include an increased number of days open, reduced conception rate, and larger number of cows suffering different types of anestrus. Once becomes pregnant, heat stress affects also the reproductive success of the cow through its direct effects on the ovary, uterus, gametes, embryo, and early fetus. This article reviews current knowledge of the effects of heat stress on fertility in dairy cows and the hormonal strategies used to mitigate these effects at the farm level. Administration of GnRH at the moment of artificial insemination can improve the conception rate. Breeding synchronization protocols for fixed-time insemination may reduce the calving conception interval and the number of services per conception. Progesterone-based protocols seem resolve better the reproductive disorders related to a hot environment (anestrus) than GnRH-based protocols. The use of combinations of GnRH, eCG, and hCG in progesterone-based protocols can improve results. Progesterone supplementation during the late embryonic and/or early fetal period would be useful in curtailing pregnancy losses, mainly in single pregnancies, whereas a more positive effect of treatment with GnRH than progesterone has been found in twin pregnancies. Melatonin therapy is emerging as a promising strategy to improve the natural reproductive performance of cows suffering conditions of heat stress. Copyright © 2015 Elsevier Inc. All rights reserved.

Towards an Experimental Protocol for the Study of Induction Heating in Asphalt Mastics

NARCIS (Netherlands)

Apostolidis, P.; Liu, X.; Scarpas, Athanasios; van Bochove, G; van de Ven, M.F.C.

2016-01-01

The development of asphalt mixtures with improved electrical and thermal properties is crucial in terms of producing suitable mixtures for the induction heating without losing their durability. The main scope of this research is to evaluate experimentally the impact of filler-sized electrically

Promotional study for joint implementation program. Energy conservation and efficiency improvement for district heating system in Tashkent, Uzbekistan

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

For the purpose of reducing greenhouse effect gas emissions, a study was carried out for repair/improvement of the district heating system in Tashkent City, the Republic of Uzbekistan. In the project, the following were studied: heightening of electrical insulation of the total pipeline, improvement in efficient utilization of heat energy in the thermal plant. As to the existing pipeline, heat loss is improved by 0-5% by changing it to electrical insulation pipe. In relation to the thermal plant, studied were cogeneration facility A using three 4MW gas turbines and combined cycle cogeneration facility B using two 40MW gas turbines. As a result, the amount of energy saving was 11,370 toe/y in pipeline, 12,750 toe/y in facility A and 69,000 toe/y in facility B. Further, the reduction amount of greenhouse effect gas emissions was 27,200t-CO2/y in pipeline, 30,500t-CO2/y in facility A and 164,900t-CO2/y in facility B. (NEDO)

Temporary heat storage by using combined heat and power in supplementary lighted greenhouses Proceedings of the Third International Symposium on Artificial Lighting in Horticulture

NARCIS (Netherlands)

Huijs, J.P.G.

1997-01-01

Because of better utilization possibilities of the produced heat, decentrally located combined heat and power installations achieve a higher energetic efficiency than producing heat and power separately. However, efficiency depends considerably on synchronism of heat and electricity demand. Using a

Estimating Nitrogen Availability of Heat-Dried Bio solids

International Nuclear Information System (INIS)

Cogger, C.G.; Bary, A.I.; Myhre, E.A.

2011-01-01

As heat-dried bio solids become more widely produced and marketed, it is important to improve estimates of N availability from these materials. Objectives were to compare plant-available N among three different heat-dried bio solids and determine if current guidelines were adequate for estimating application rates. Heat-dried bio solids were surface applied to tall fescue (Festuca arundinacea Schreb.) in Washington State, USA, and forage yield and N uptake measured for two growing seasons following application. Three rates of urea and a zero-N control were used to calculate N fertilizer efficiency regressions. Application year plant-available N (estimated as urea N equivalent) for two bio solids exceeded 60% of total N applied, while urea N equivalent for the third bio solids was 45%. Residual (second-year) urea N equivalent ranged from 5 to 10%. Guidelines for the Pacific Northwest USA recommend mineralization estimates of 35 to 40% for heat-dried bio solids, but this research shows that some heat-dried materials fall well above that range.

Improving cancer treatment with cyclotron produced radionuclides. Progress report

Energy Technology Data Exchange (ETDEWEB)

Larson, S.M.; Finn, R.D.

1993-11-01

This report describes our continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section will be employed in the Pharmacology and Immunology sections during the next year. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

Electrical energy use in different heating systems for early weaned piglets

Energy Technology Data Exchange (ETDEWEB)

Sarubbi, J. [Federal Univ. of Santa Maria, Palmeira das Missoes, RS (Brazil). Dept. of Animal Science; Campinas State Univ., Sao Paulo (Brazil). College of Agricultural Engineering; Rossi, L.A.; Moura, D.J.; Oliveira, R.A.; David, E. [Campinas State Univ., Sao Paulo (Brazil). College of Agricultural Engineering

2010-07-01

This study compared the electrical energy use and thermal comfort conditions associated with 3 heating technologies used in piglet farms. Heating systems for piglets in nursery and farrowing can be improved to conserve energy without affecting the welfare of the animals. The evaluation was conducted at a commercial farm in a subtropical climate area of Brazil. Each treatment involved 150 weaned piglets at 21 days-old. The systems were designed to keep the piglets at 28 to 30 degrees C for 14 days. Suspended electrical resistors, heated floors and convection heating were the 3 heating technologies examined during this study which evaluated the electrical energy consumption, maximum power demand requirements and dry-bulb temperature. The study also assessed the specific consumption in terms of kWh/kg of live produced body mass as well as the efficiency of heating system in terms of degrees C per cubic metre of air. In terms of electrical energy use, the best heating system was the heated floor. However, the electrical resistance heating system was the best in terms of thermal comfort.

Improving the Material Response for Slow Heat of Energetic Materials

Energy Technology Data Exchange (ETDEWEB)

Nichols, A L

2010-03-08

The goal of modern high explosive slow heat cookoff modeling is to understand the level of mechanical violence. This requires understanding the coupled thermal-mechanical-chemical system that such an environment creates. Recent advances have improved our ability to predict the time to event, and we have been making progress on predicting the mechanical response. By adding surface tension to the product gas pores in the high explosive, we have been able to reduce the current model's tendency to overpressurize confinement vessels. We describe the model and demonstrate how it affects a LX-10 STEX experiment. Issues associated with current product gas equations of state are described and examined.

Carbonate Precipitates During Heat Evolution in FP-Type Cells

International Nuclear Information System (INIS)

Bruce L. Cain

2000-01-01

In previous work, we reported measurement of large amounts of heat generated during experiments using an FP-type open cell with concentrated LiOH/D 2 O electrolytes and thin-film Pd cathodes. During the heat evolution in several runs, which produced >100 W for more than 20 h, we consistently observed the concomitant evolution of gases from the electrolyte and the precipitation of large amounts of lithium carbonate. The carbonate production was clearly visible during production of heat, creating an opaque electrolyte even during long periods with no electrolysis current. These results indicated an unusual chemical reaction, either catalyzed by the heating process or possibly creating the heat itself. The total energy released during the earlier experiments was ∼7 MJ, while the heat of formation for the lithium carbonate in the cell was only 0.8 MJ. Hence, only ∼10% of the heat signatures from these experiments can be attributed to the precipitate formation, the balance of the heat presumably arising from nonchemical sources in the cells. The earlier experiments that produced heat also suffered from problems of reproducibility, with only 5 of 38 runs producing any heat at all. The unsuccessful runs also did not produce precipitates, and the only gas produced in these cells was due to the normal electrolysis of D 2 O to produce oxygen and deuterium in the electrodes. Recent work has focused on recreating the chemical precipitation reaction, in efforts to understand and/or trigger the heat production process. With findings from these experiments, new experiments were conducted using larger (1 L LiOH/D 2 O) cells with Pt anodes and Pd film cathodes immersed but left open-circuited. After the addition of H 2 O 2 , and subsequent heating and cooling, these cells visually reproduced the precipitation and gas evolution of the earlier heat-producing runs. However, these new runs only produced a few watts of power for several minutes, consistent with the normal exothermal

Solar heating system

Science.gov (United States)

Schreyer, James M.; Dorsey, George F.

1982-01-01

An improved solar heating system in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75.degree. to 180.degree. F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing and releasing heat for distribution.

Thermal Profile of the Lunar Interior Constrained by Revised Estimates of Concentrations of Heat Producing Elements

Science.gov (United States)

Fuqua-Haviland, H.; Panovska, S.; Mallik, A.; Bremner, P. M.; McDonough, W. F.

2017-12-01

Constraining the heat producing element (HPE) concentrations of the Moon is important for understanding the thermal state of the interior. The lunar HPE budget is debated to be suprachondritic [1] to chondritic [2]. The Moon is differentiated, thus, each reservoir has a distinct HPE signature complicating this effort. The thermal profile of the lunar interior has been constructed using HPE concentrations of an ordinary chondrite (U = 0.0068 ppm; Th = 0.025 ppm; K = 17 ppm) which yields a conservative low estimate [2, 3, 4]. A later study estimated the bulk lunar mantle HPE concentrations (U = 0.039 ppm; Th = 0.15 ppm; K = 212 ppm) based on measurements of Apollo pyroclastic glasses [5] assuming that these glasses represent the least fractionated, near-primary lunar mantle melts, hence, are the best proxies for capturing mantle composition. In this study, we independently validate the revised estimate by using HPE concentrations [5] to construct a conductive lunar thermal profile, or selenotherm. We compare our conductive profile to the range of valid temperatures. We demonstrate the HPE concentrations reported by [5], when used in a simple 1D spherical thermal conduction equation, yield an impossibly hot mantle with temperatures in excess of 4,000 K (Fig 1). This confirms their revised estimate is not representative of the bulk lunar mantle, and perhaps only representative of a locally enriched mantle domain. We believe that their Low-Ti avg. source estimate (Th = 0.055 ppm, Th/U=4; K/U=1700), with the least KREEP assimilation is the closest representation of the bulk lunar mantle, producing 3E-12 W/kg of heat. This estimate is close to that of the Earth (5E-12 W/kg), indicating that the bulk Earth and lunar mantles are similar in their HPE constituents. We have used the lunar mantle heat production, in conjunction with HPE estimates of the Fe-Ti-rich cumulates (high Ti-source estimate from [5]) and measurements of crustal ferroan anorthite [6], to capture the

Compression Pad Cavity Heating Augmentation on Orion Heat Shield

Science.gov (United States)

Hollis, Brian R.

2011-01-01

An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion Crew Exploration Vehicle heat shield. Testing was conducted in Mach 6 and 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The effects of cavity dimensions on boundary-layer transition and heating augmentation levels were studied. Correlations were developed for transition onset and for the average cavity-heating augmentation.

Crawl space assisted heat pump. [using stored ground heat

Science.gov (United States)

Ternes, M. P.

1980-01-01

A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described.

Method for reducing excess heat supply experienced in typical Chinese district heating systems by achieving hydraulic balance and improving indoor air temperature control at the building level

International Nuclear Information System (INIS)

Zhang, Lipeng; Gudmundsson, Oddgeir; Thorsen, Jan Eric; Li, Hongwei; Li, Xiaopeng; Svendsen, Svend

2016-01-01

A common problem with Chinese district heating systems is that they supply more heat than the actual heat demand. The reason for this excess heat supply is the general failure to use control devices to adjust the indoor temperature and flow in the building heating systems in accordance with the actual heat demand. This results in 15–30% of the total supplied heat being lost. This paper proposes an integrated approach that aims to reduce the excess heat loss by introducing pre-set thermostatic radiator valves combined with automatic balancing valves. Those devices establish hydraulic balance, and stabilize indoor temperatures. The feasibility and the energy consumption reduction of this approach were verified by means of simulation and a field test. By moving the system from centrally planned heat delivery to demand-driven heat delivery, excess heat loss can be significantly reduced. Results show that once the hydraulic balance is achieved and indoor temperatures are controlled with this integrated approach, 17% heat savings and 42.8% pump electricity savings can be achieved. The energy savings will also have a positive environmental effect with seasonal reductions of 11 kg CO_2, 0.1 kg SO_2, and 0.03 kg NO_x per heating square meter for a typical case in Harbin. - Highlights: • Two real cases reflect the temperature and flow control situation of heating systems in China. • Pre-set radiator valves with automatic balancing valves create dynamic hydraulic balance. • IDA-ICE simulation shows 17% heat saving and 48% pump electricity saving. • This approach can improve the comfort level of multi-storey/high-rise residential buildings. • This approach can reduce excess heat supply and bring out positive environmental impacts.

Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine

Science.gov (United States)

Ma, Zheshu; Chen, Hua; Zhang, Yong

2017-09-01

The increase of ship's energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO) is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI) and energy efficiency operational indicator (EEOI) aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.

Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine

Directory of Open Access Journals (Sweden)

Ma Zheshu

2017-09-01

Full Text Available The increase of ship’s energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI and energy efficiency operational indicator (EEOI aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.

Study of temperature distribution of pipes heated by moving rectangular gauss distribution heat source. Development of pipe outer surface irradiated laser stress improvement process (L-SIP)

International Nuclear Information System (INIS)

Ohta, Takahiro; Kamo, Kazuhiko; Asada, Seiji; Terasaki, Toshio

2009-01-01

The new process called L-SIP (outer surface irradiated Laser Stress Improvement Process) is developed to improve the tensile residual stress of the inner surface near the butt welded joints of pipes in the compression stress. The temperature gradient occurs in the thickness of pipes in heating the outer surface rapidly by laser beam. By the thermal expansion difference between the inner surface and the outer surface, the compression stress occurs near the inner surface of pipes. In this paper, the theoretical equation for the temperature distributions of pipes heated by moving rectangular Gauss distribution heat source on the outer surface is derived. The temperature histories of pipes calculated by theoretical equation agree well with FEM analysis results. According to the theoretical equation, the controlling parameters of temperature distributions and histories are q/2a y , vh, a x /h and a y /h, where q is total heat input, a y is heat source length in the axial direction, a x is Gaussian radius of heat source in the hoop direction, ν is moving velocity, and h is thickness of the pipe. The essential variables for L-SIP, which are defined on the basis of the measured temperature histories on the outer surface of the pipe, are Tmax, F 0 =kτ 0 /h 2 , vh, W Q and L Q , where Tmax is maximum temperature on the monitor point of the outer surface, k is thermal diffusivity coefficient, τ 0 is the temperature rise time from 100degC to maximum temperature on the monitor point of the outer surface, W Q is τ 0 x ν, and L Q is the uniform temperature length in the axial direction. It is verified that the essential variables for L-SIP match the controlling parameters by the theoretical equation. (author)

Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

Directory of Open Access Journals (Sweden)

Minwei Yao

2017-01-01

Full Text Available Electrospun membranes are gaining interest for use in membrane distillation (MD due to their high porosity and interconnected pore structure; however, they are still susceptible to wetting during MD operation because of their relatively low liquid entry pressure (LEP. In this study, post-treatment had been applied to improve the LEP, as well as its permeation and salt rejection efficiency. The post-treatment included two continuous procedures: heat-pressing and annealing. In this study, annealing was applied on the membranes that had been heat-pressed. It was found that annealing improved the MD performance as the average flux reached 35 L/m2·h or LMH (>10% improvement of the ones without annealing while still maintaining 99.99% salt rejection. Further tests on LEP, contact angle, and pore size distribution explain the improvement due to annealing well. Fourier transform infrared spectroscopy and X-ray diffraction analyses of the membranes showed that there was an increase in the crystallinity of the polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP membrane; also, peaks indicating the α phase of polyvinylidene fluoride (PVDF became noticeable after annealing, indicating some β and amorphous states of polymer were converted into the α phase. The changes were favorable for membrane distillation as the non-polar α phase of PVDF reduces the dipolar attraction force between the membrane and water molecules, and the increase in crystallinity would result in higher thermal stability. The present results indicate the positive effect of the heat-press followed by an annealing post-treatment on the membrane characteristics and MD performance.

THE EFFECT OF HEAT TREATMENT ON THE DURABILITY OF BAMBOO Gigantochloa scortechinii

Directory of Open Access Journals (Sweden)

Norashikin Kamarudin

2012-07-01

Full Text Available Bamboo signifies as one of the fastest growing plants and it can be used for various products. In tropical countries such as Indonesia and Malaysia, bamboo is abundantly available at reasonable prices, therefore it is used for numerous purposes. However, as lignocellulosic material, bamboo is susceptible to fungal and insect attacks. Heat treatment is an option to improve bamboo's durability. The objective of this study was to improve the durability of bamboo using hot oil palm treatment. A Malaysian grown bamboo species, Buluh Semantan (Gigantochloa scortechinii, as a study material was soaked in hot oil palm for various temperatures and soaking time, before being inoculated with the basidiomycete Coriolus versicolor in an agar block test. The results demonstrated that the longer the heating time, the more improved the durability of bamboo. Altering the temperature in the palm oil treatment produced varying results. Bamboo blocks that heated in hot oil palm at 100°C for 60 minutes shows considerably less weight eduction that indicates less fungal attack. Overall, the higher the temperature, the better the durability of bamboo. Please indicates what the meaning of heat treatment in this experiment, it is not clear.

Improving Heat Transfer Performance of Printed Circuit Boards

Science.gov (United States)

Schatzel, Donald V.

2009-01-01

This paper will explore the ability of printed circuit boards laminated with a Carbon Core Laminate to transfer heat vs. standard printed circuit boards that use only thick layers of copper. The paper will compare the differences in heat transfer performance of printed circuit boards with and without CCL.

Review, modeling, Heat Integration, and improved schemes of Rectisol®-based processes for CO2 capture

International Nuclear Information System (INIS)

Gatti, Manuele; Martelli, Emanuele; Marechal, François; Consonni, Stefano

2014-01-01

The paper evaluates the thermodynamic performances and the energy integration of alternative schemes of a methanol absorption based acid gas removal process designed for CO 2 Capture and Storage. More precisely, this work focuses the attention on the Rectisol ® process specifically designed for the selective removal of H 2 S and CO 2 from syngas produced by coal gasification. The study addresses the following issues: (i) perform a review of the Rectisol ® schemes proposed by engineers and researchers with the purpose of determining the best one for CO 2 capture and storage; (ii) calibrate the PC-SAFT equation of state for CH 3 OH–CO 2 –H 2 S–H 2 –CO mixtures at conditions relevant to the Rectisol ® process; (iii) evaluate the thermodynamic performances and optimize the energy integration of a “Reference” scheme derived from those available in the literature; (iv) identify and assess alternative Rectisol ® schemes with optimized performance for CO 2 Capture and Storage and Heat Integration with utilities. On the basis of the analysis of the Composite Curves of the integrated process, we propose some possible improvements at the level of the process configuration, like the introduction of mechanical vapor recompression and the development of a two stage regeneration arrangement. - Highlights: • Comprehensive review of the Rectisol ® process configurations and applications. • Calibration of PC-SAFT equation of state for Rectisol ® -relevant mixtures. • Detailed process simulation and optimized Heat Integration, and utility design. • Development of alternative Rectisol ® schemes optimized for CO 2 Capture

Effect of Filling Type and Heating Method on Prevalence of Listeria species and Listeria monocytogenes in Dumplings Produced in Poland.

Science.gov (United States)

Szymczak, Barbara; Dąbrowski, Waldemar

2015-05-01

The count of Listeria monocytogenes was determined, before and after heat treatment, in 200 samples of dumplings of 9 brands and with different types of stuffing. Analyses were conducted according to ISO 11290-1 standard and with real-time PCR method. The highest count of L. monocytogenes was found in meat dumplings (10(2) to 10(4) CFU/g), whereas products with white cheese-potato stuffing and vegetable-mushroom stuffing contained significantly less Listeria, 20 to 80 and 5 to 32 CFU/g, respectively. In cooled meat dumplings the extent of contamination depended significantly on the producer. In addition, a significant (P monocytogenes in meat dumplings. In contrast, the microwave heating applied for 2 min at 600 W only reduced the count of L. monocytogenes by 1 to 2 logs. Hence, the microwave heating failed to reduce the risk of infection with this pathogen below the level permissible in the EU regulation, especially in the most contaminated samples. In this case, the efficacy of microwave heating was significantly (P monocytogenes (rho = 0.626), then by meat content in the stuffing (0.476), and to the lowest extent--by the type of meat (0.415 to 0.425). However, no Listeria sp. and L. monocytogenes were isolated from cooked dumplings with fruits (strawberries or blueberries). © 2015 Institute of Food Technologists®

State of the art on nuclear heating measurement methods and expected improvements in zero power research reactors

International Nuclear Information System (INIS)

Le Guillou, M.; Gruel, A.; Destouches, C.; Blaise, P.

2017-01-01

The paper focuses on the recent methodological advances suitable for nuclear heating measurements in zero power research reactors. This bibliographical work is part of an experimental approach currently in progress at CEA Cadarache, aiming at optimizing photon heating measurements in low-power research reactors. It provides an overview of the application fields of the most widely used detectors, namely thermoluminescent dosimeters (TLDs) and optically stimulated luminescent dosimeters. Starting from the methodology currently implemented at CEA, the expected improvements relate to the experimental determination of the neutron component, which is a key point conditioning the accuracy of photon heating measurements in mixed n-γ field. A recently developed methodology based on the use of "7Li and "6Li-enriched TLDs, pre-calibrated both in photon and neutron fields, is a promising approach to de-convolute the 2 components of nuclear heating. We also investigate the different methods of optical fiber dosimetry, with a view to assess the feasibility of online photon heating measurements, whose primary benefit is to overcome constraints related to the withdrawal of dosimeters from the reactor immediately after irradiation. Moreover, a fiber-using setup could allow measuring the instantaneous dose rate during irradiation, as well as the delayed photon dose after reactor shutdown. Some insights from potential further developments are given. Obviously, any improvement of the technique has to lead to a measurement uncertainty at least equal to that of the currently used methodology (∼5% at 1 σ). (authors)

State of the art on nuclear heating measurement methods and expected improvements in zero power research reactors

Directory of Open Access Journals (Sweden)

Le Guillou Mael

2017-01-01

Full Text Available The paper focuses on the recent methodological advances suitable for nuclear heating measurements in zero power research reactors. This bibliographical work is part of an experimental approach currently in progress at CEA Cadarache, aiming at optimizing photon heating measurements in low-power research reactors. It provides an overview of the application fields of the most widely used detectors, namely thermoluminescent dosimeters (TLDs and optically stimulated luminescent dosimeters. Starting from the methodology currently implemented at CEA, the expected improvements relate to the experimental determination of the neutron component, which is a key point conditioning the accuracy of photon heating measurements in mixed n–γ field. A recently developed methodology based on the use of 7Li and 6Li-enriched TLDs, precalibrated both in photon and neutron fields, is a promising approach to deconvolute the two components of nuclear heating. We also investigate the different methods of optical fiber dosimetry, with a view to assess the feasibility of online photon heating measurements, whose primary benefit is to overcome constraints related to the withdrawal of dosimeters from the reactor immediately after irradiation. Moreover, a fibered setup could allow measuring the instantaneous dose rate during irradiation, as well as the delayed photon dose after reactor shutdown. Some insights from potential further developments are given. Obviously, any improvement of the technique has to lead to a measurement uncertainty at least equal to that of the currently used methodology (∼5% at 1σ.

Analysis of an optimal resorption cogeneration using mass and heat recovery processes

International Nuclear Information System (INIS)

Lu, Yiji; Wang, Yaodong; Bao, Huashan; Yuan, Ye; Wang, Liwei; Roskilly, Anthony Paul

2015-01-01

Highlights: • Resorption cogeneration for electricity and refrigeration generation. • Mass and heat recovery to further improve the performance. • The first and second law analysis. - Abstract: This paper presents an optimised resorption cogeneration using mass and heat recovery to improve the performance of a novel resorption cogeneration fist proposed by Wang et al. This system combines ammonia-resorption technology and expansion machine into one loop, which is able to generate refrigeration and electricity from low-grade heat sources such as solar energy and industrial waste heat. Two sets of resorption cycle are designed to overcome the intermittent performance of the chemisorption and produce continuous/simultaneous refrigeration and electricity. In this paper, twelve resorption working pairs of salt complex candidates are analysed by the first law analysis using Engineering Equation Solver (EES). The optimal resorption working pairs from the twelve candidates under the driven temperature from 100 °C to 300 °C are identified. By applying heat/mass recovery, the coefficient of performance (COP) improvement is increased by 38% when the high temperature salt (HTS) is NiCl 2 and by 35% when the HTS is MnCl 2 . On the other hand, the energy efficiency of electricity has also been improved from 8% to 12% with the help of heat/mass recovery. The second law analysis has also been applied to investigate the exergy utilisation and identify the key components/processes. The highest second law efficiency is achieved as high as 41% by the resorption working pair BaCl 2 –MnCl 2 under the heat source temperature at 110 °C.

Heat Pipes

Science.gov (United States)

1990-01-01

Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than 57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was 28,706, and that figures out to a cost reduction.

Improving Energy Efficiency In Thermal Oil Recovery Surface Facilities

Energy Technology Data Exchange (ETDEWEB)

Murthy Nadella, Narayana

2010-09-15

Thermal oil recovery methods such as Cyclic Steam Stimulation (CSS), Steam Assisted Gravity Drainage (SAGD) and In-situ Combustion are being used for recovering heavy oil and bitumen. These processes expend energy to recover oil. The process design of the surface facilities requires optimization to improve the efficiency of oil recovery by minimizing the energy consumption per barrel of oil produced. Optimization involves minimizing external energy use by heat integration. This paper discusses the unit processes and design methodology considering thermodynamic energy requirements and heat integration methods to improve energy efficiency in the surface facilities. A design case study is presented.

Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells.

Directory of Open Access Journals (Sweden)

Sae Tanaka

Full Text Available Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble and SAHS (Secretory Abundant Heat Soluble proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble, as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments.

Electron cyclotron heating (ECH) of tokamak plasmas

International Nuclear Information System (INIS)

Hoshino, Katsumichi

1990-01-01

Electron cyclotron heating (ECH) is one of the intense methods of plasma heating, and which utilizes the collisionless electron-cyclotron-resonance-interaction between the launched electromagnetic waves (called electron cyclotron waves) and electrons which are one of the constituents of the high temperature plasmas. Another constituent, namely the ions which are subject to nuclear fusion, are heated indirectly but strongly and instantly (in about 0.1 s) by the collisions with the ECH-heated electrons in the fusion plasmas. The recent progress on the development of high-power and high-frequency millimeter-wave-source enabled the ECH experiments in the middle size tokamaks such as JFT-2M (Japan), Doublet III (USA), T-10 (USSR) etc., and ECH has been demonstrated to be the sure and intense plasma heating method. The ECH attracts much attention for its remarkable capabilities; to produce plasmas (pre-ionization), to heat plasmas, to drive plasma current for the plasma confinement, and recently especially by the localization and the spatial controllability of its heating zone, which is beneficial for the fine controls of the profiles of plasma parameters (temperature, current density etc.), for the control of the magnetohydrodynamic instabilities, or for the optimization/improvement of the plasma confinement characteristics. Here, the present status of the ECH studies on tokamak plasmas are reviewed. (author)

Design heating test section HeaTiNG-02

International Nuclear Information System (INIS)

Riswan Djambiar; Sagino; Dedy Haryanto; Joko Prasetio Witoko

2013-01-01

HeaTiNG-02 is a component test loop BETA which serves as a heater in conducting experimental heat transfer processes in two-phase flow in narrow slit-shaped plate, considering this phenomenon is one of the conditions postulated accident scenarios a NPP type PWR. To produce heat for the heating component takes the AC power the source voltage can be set from 0 Volts to 220 Volts with no more than a maximum power of 25 KVA. To obtain the thermal conditions on HeaTiNG-02 heating wire dimensions need to be determined and the corresponding voltage so that it will an expected power. Determination of the dimensions of the heater wire through calculations using electricity formulations. Retrieved draft heater test BETA (UUB) HeaTiNG-02 use material super kanthal (FeCuAl) in diameter (Ø) = 2 mm and wire length 3770 mm. Voltage regulators with a maximum power of 25 kVA with a minimum voltage of 0 volts and a maximum of 220 volts. Heater is used as the base to form refractory stone trench. (author)

Flat plate solar air heater with latent heat storage

Science.gov (United States)

Touati, B.; Kerroumi, N.; Virgone, J.

2017-02-01

Our work contains two parts, first is an experimental study of the solar air heater with a simple flow and forced convection, we can use thatlaste oneit in many engineering's sectors as solardrying, space heating in particular. The second part is a numerical study with ansys fluent 15 of the storage of part of this solar thermal energy produced,using latent heat by using phase change materials (PCM). In the experimental parts, we realize and tested our solar air heater in URER.MS ADRAR, locate in southwest Algeria. Where we measured the solarradiation, ambient temperature, air flow, thetemperature of the absorber, glasses and the outlet temperature of the solar air heater from the Sunrise to the sunset. In the second part, we added a PCM at outlet part of the solar air heater. This PCM store a part of the energy produced in the day to be used in peak period at evening by using the latent heat where the PCMs present a grateful storagesystem.A numerical study of the fusion or also named the charging of the PCM using ANSYS Fluent 15, this code use the method of enthalpies to solve the fusion and solidification formulations. Furthermore, to improve the conjugate heat transfer between the heat transfer fluid (Air heated in solar plate air heater) and the PCM, we simulate the effect of adding fins to our geometry. Also, four user define are write in C code to describe the thermophysicalpropriety of the PCM, and the inlet temperature of our geometry which is the temperature at the outflow of the solar heater.

Heat transfer problems for the production of hydrogen from geothermal energy

International Nuclear Information System (INIS)

Sigurvinsson, J.; Mansilla, C.; Arnason, B.; Bontemps, A.; Marechal, A.; Sigfusson, T.I.; Werkoff, F.

2006-01-01

Electrolysis at low temperature is currently used to produce Hydrogen. From a thermodynamic point of view, it is possible to improve the performance of electrolysis while functioning at high temperature (high temperature electrolysis: HTE). That makes it possible to reduce energy consumption but requires a part of the energy necessary for the dissociation of water to be in the form of thermal energy. A collaboration between France and Iceland aims at studying and then validating the possibilities of producing hydrogen with HTE coupled with a geothermal source. The influence of the exit temperature on the cost of energy consumption of the drilling well is detailed. To vaporize the water to the electrolyser, it should be possible to use the same technology currently used in the Icelandic geothermal context for producing electricity by using a steam turbine cycle. For heating the steam up to the temperature needed at the entrance of the electrolyser three kinds of heat exchangers could be used, according to specific temperature intervals

Energy efficiency improvements utilising mass flow control and a ring topology in a district heating network

International Nuclear Information System (INIS)

Laajalehto, Tatu; Kuosa, Maunu; Mäkilä, Tapio; Lampinen, Markku; Lahdelma, Risto

2014-01-01

Heating and cooling have a major role in the energy sector, covering 46% of total final energy use worldwide. District heating (DH) is a significant technology for improving the energy efficiency of heating systems in communities, because it enables waste heat sources to be utilised economically and therefore significantly reduces the environmental impacts of power generation. As a result of new and more stringent construction regulations for buildings, the heat demands of individual buildings are decreasing and more energy-efficient heating systems have to be developed. In this study, the energy efficiency of a new DH system which includes both a new control system called mass flow control and a new network design called a ring network is examined. A topology in the Helsinki region is studied by using a commercial DH network modelling tool, Grades Heating. The district heating network is attached to a wood-burning heat station which has a heat recovery system in use. Examination is performed by means of both technical and economic analysis. The new non-linear temperature programme that is required is adopted for supply and return temperatures, which allows greater temperature cooling and smaller flow rates. Lower district heating water temperatures are essential when reducing the heat losses in the network and heat production. Mass flow control allows smaller pressure drops in the network and thus reduces the pumping power. The aim of this study was to determine the most energy-efficient DH water supply temperatures in the case network. If the ring network design is utilised, the district heating system is easier to control. As a result the total heat consumption within the heating season is reduced compared to traditional DH systems. On the basis of the results, the new DH system is significantly more energy-efficient in the case network that was examined than the traditional design. For example, average energy losses within the constraints (which consist of heat

Absorption-heat-pump system

Science.gov (United States)

Grossman, G.; Perez-Blanco, H.

1983-06-16

An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

Heat simulation via Scilab programming

Science.gov (United States)

Hasan, Mohammad Khatim; Sulaiman, Jumat; Karim, Samsul Arifin Abdul

2014-07-01

This paper discussed the used of an open source sofware called Scilab to develop a heat simulator. In this paper, heat equation was used to simulate heat behavior in an object. The simulator was developed using finite difference method. Numerical experiment output show that Scilab can produce a good heat behavior simulation with marvellous visual output with only developing simple computer code.

Cyclic process for producing methane from carbon monoxide with heat removal

Science.gov (United States)

Frost, Albert C.; Yang, Chang-lee

1982-01-01

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Method for producing bio-fuel that integrates heat from carbon-carbon bond-forming reactions to drive biomass gasification reactions

Science.gov (United States)

Cortright, Randy D [Madison, WI; Dumesic, James A [Verona, WI

2011-01-18

A low-temperature catalytic process for converting biomass (preferably glycerol recovered from the fabrication of bio-diesel) to synthesis gas (i.e., H.sub.2/CO gas mixture) in an endothermic gasification reaction is described. The synthesis gas is used in exothermic carbon-carbon bond-forming reactions, such as Fischer-Tropsch, methanol, or dimethylether syntheses. The heat from the exothermic carbon-carbon bond-forming reaction is integrated with the endothermic gasification reaction, thus providing an energy-efficient route for producing fuels and chemicals from renewable biomass resources.

Resorption heat pump

International Nuclear Information System (INIS)

Vasiliev, L.L.; Mishkinis, D.A.; Antukh, A.A.; Kulakov, A.G.; Vasiliev, L.L.

2004-01-01

Resorption processes are based on at least two solid-sorption reactors application. The most favorable situation for the resorption heat pumps is the case, when the presence of a liquid phase is impossible. From simple case--two reactors with two salts to complicated system with two salts + active carbon fiber (fabric) and two branch of the heat pump acting out of phase to produce heat and cold simultaneously, this is the topic of this research program

Resin impregnation process for producing a resin-fiber composite

Science.gov (United States)

Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

1994-01-01

Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

Preparation of functions of computer code GENGTC and improvement for two-dimensional heat transfer calculations for irradiation capsules

International Nuclear Information System (INIS)

Nomura, Yasushi; Someya, Hiroyuki; Ito, Haruhiko.

1992-11-01

Capsules for irradiation tests in the JMTR (Japan Materials Testing Reactor), consist of irradiation specimens surrounded by a cladding tube, holders, an inner tube and a container tube (from 30mm to 65mm in diameter). And the annular gaps between these structural materials in the capsule are filled with liquids or gases. Cooling of the capsule is done by reactor primary coolant flowing down outside the capsule. Most of the heat generated by fission in fuel specimens and gamma absorption in structural materials is directed radially to the capsule container outer surface. In thermal performance calculations for capsule design, an one(r)-dimensional heat transfer computer code entitled (Generalyzed Gap Temperature Calculation), GENGTC, originally developed in Oak Ridge National Laboratory, U.S.A., has been frequently used. In designing a capsule, are needed many cases of parametric calculations with respect to changes materials and gap sizes. And in some cases, two(r,z)-dimensional heat transfer calculations are needed for irradiation test capsules with short length fuel rods. Recently the authors improved the original one-dimensional code GENGTC, (1) to simplify preparation of input data, (2) to perform automatic calculations for parametric survey based on design temperatures, ect. Moreover, the computer code has been improved to perform r-z two-dimensional heat transfer calculation. This report describes contents of the preparation of the one-dimensional code GENGTC and the improvement for the two-dimensional code GENGTC-2, together with their code manuals. (author)

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

Design and evaluation of a heat recuperator for steel slags

International Nuclear Information System (INIS)

Gutiérrez Trashorras, Antonio J.; Álvarez, Eduardo Álvarez; Río González, José Luis; Suarez Cuesta, José Manuel; Bernat, Jorge Xiberta

2013-01-01

New techniques for emissions reduction and energy efficiency are important challenges of the steel industry. Although great advantages have been reached in these fields, there are still new opportunities. One of them is the possible development of systems to recover energy from slags. The recent policies that encourage the use of renewable and alternative energies determine a favorable scenario for the development of new techniques of heat recovering. In this context, this article presents a new heat recuperation system for the slags produced in the factories of Arcelor–Mittal in Asturias (Spain) and study in detail the design of an innovative slags heat exchanger. To adjust its performance and to determine the influence of the geometric and flow design parameters, the heat exchanger has been simulated using numerical analysis software (CFD). -- Highlights: • A new design of a heat recuperator for slags energy recovery is presented. • The effects of the design parameters have been studied with a numerical model. • Refractory materials with high thermal conductivity improve heat recuperation

Improvement of Xylose Fermentation Ability under Heat and Acid Co-Stress in Saccharomyces cerevisiae Using Genome Shuffling Technique

Directory of Open Access Journals (Sweden)

Kentaro Inokuma

2017-12-01

Full Text Available Xylose-assimilating yeasts with tolerance to both fermentation inhibitors (such as weak organic acids and high temperature are required for cost-effective simultaneous saccharification and cofermentation (SSCF of lignocellulosic materials. Here, we demonstrate the construction of a novel xylose-utilizing Saccharomyces cerevisiae strain with improved fermentation ability under heat and acid co-stress using the drug resistance marker-aided genome shuffling technique. The mutagenized genome pools derived from xylose-utilizing diploid yeasts with thermotolerance or acid tolerance were shuffled by sporulation and mating. The shuffled strains were then subjected to screening under co-stress conditions of heat and acids, and the hybrid strain Hyb-8 was isolated. The hybrid strain displayed enhanced xylose fermentation ability in comparison to both parental strains under co-stress conditions of heat and acids. Hyb-8 consumed 33.1 ± 0.6 g/L xylose and produced 11.1 ± 0.4 g/L ethanol after 72 h of fermentation at 38°C with 20 mM acetic acid and 15 mM formic acid. We also performed transcriptomic analysis of the hybrid strain and its parental strains to screen for key genes for multiple stress tolerances. We found that 13 genes, including 5 associated with cellular transition metal ion homeostasis, were significantly upregulated in Hyb-8 compared to levels in both parental strains under co-stress conditions. The hybrid strain Hyb-8 has strong potential for cost-effective SSCF of lignocellulosic materials. Moreover, the transcriptome data gathered in this study will be useful for understanding the mechanisms of multiple tolerance to high temperature and acids in yeast and facilitate the development of robust yeast strains for SSCF.

Heat buffers improve capacity and exploitation degree of geothermal energy sources

NARCIS (Netherlands)

Ooster, A.van t; Wit, J. de; Janssen, E.G.O.N.; Ruigrok, J.

2008-01-01

This research focuses on the role of heat buffers to support optimal use of combinations of traditional and renewable heat sources like geothermal heat for greenhouse heating. The objective was to determine the contribution of heat buffers to effective new combinations of resources that satisfy

Space Launch System Base Heating Test: Experimental Operations & Results

Science.gov (United States)

Dufrene, Aaron; Mehta, Manish; MacLean, Matthew; Seaford, Mark; Holden, Michael

2016-01-01

NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Test methodology and conditions are presented, and base heating results from 76 runs are reported in non-dimensional form. Regions of high heating are identified and comparisons of various configuration and conditions are highlighted. Base pressure and radiometer results are also reported.

The improving of the heat networks operating process under the conditions of the energy efficiency providing

Directory of Open Access Journals (Sweden)

Blinova Tatiana

2016-01-01

Full Text Available Among the priorities it is important to highlight the modernization and improvement of energy efficiency of housing and communal services, as well as the transition to the principle of using the most efficient technologies used in reproduction (construction, creation of objects of municipal infrastructure and housing modernization. The main hypothesis of this study lies in the fact that in modern conditions the realization of the most important priorities of the state policy in the sphere of housing and communal services, is possible in the conditions of use of the most effective control technologies for the reproduction of thermal networks. It is possible to raise the level of information security Heat Distribution Company, and other market participants by improving business processes through the development of organizational and economic mechanism in the conditions of complex monitoring of heat network operation processes

Heat-stable, FE-dependent alcohol dehydrogenase for aldehyde detoxification

Science.gov (United States)

Elkins, James G.; Clarkson, Sonya

2018-04-24

The present invention relates to microorganisms and polypeptides for detoxifying aldehydes associated with industrial fermentations. In particular, a heat-stable, NADPH- and iron-dependent alcohol dehydrogenase was cloned from Thermoanaerobacter pseudethanolicus 39E and displayed activity against a number of aldehydes including inhibitory compounds that are produced during the dilute-acid pretreatment process of lignocellulosic biomass before fermentation to biofuels. Methods to use the microorganisms and polypeptides of the invention for improved conversion of bio mass to biofuel are provided as well as use of the enzyme in metabolic engineering strategies for producing longer-chain alcohols from sugars using thermophilic, fermentative microorganisms.

Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

KAUST Repository

Katterbauer, Klemens

2014-01-01

Enhanced recovery methods have become significant in the industry\\'s drive to increase recovery rates from oil and gas reservoirs. For heavy oil reservoirs, the immobility of the oil at reservoir temperatures, caused by its high viscosity, limits the recovery rates and strains the economic viability of these fields. While thermal recovery methods, such as steam injection or THAI, have extensively been applied in the field, their success has so far been limited due to prohibitive heat losses and the difficulty in controlling the combustion process. Electromagnetic (EM) heating via high-frequency EM radiation has attracted attention due to its wide applicability in different environments, its efficiency, and the improved controllability of the heating process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase recovery rates. Limited research has been undertaken so far to capture the nonlinear reservoir dynamics and significantly varying flow rates for thermally heated heavy oil reservoir that may notably change production rates and render conventional history matching frameworks more challenging. We present a new history matching framework for EM heated heavy oil reservoirs incorporating cross-well seismic imaging. Interfacing an EM heating solver to a reservoir simulator via Andrade’s equation, we couple the system to an ensemble Kalman filter based history matching framework incorporating a cross-well seismic survey module. With increasing power levels and heating applied to the heavy oil reservoirs, reservoir dynamics change considerably and may lead to widely differing production forecasts and increased uncertainty. We have shown that the incorporation of seismic observations into the EnKF framework can significantly enhance reservoir simulations, decrease forecasting

Biological effects of intracorporeal radioisotope heat sources

International Nuclear Information System (INIS)

Gillis, M.F.; Decker, J.R.; Karagianes, M.T.

1976-01-01

A surface heat flux of 0.04 watts/cm 2 from a retroperitoneal implant with healthy surface ingrowth of tissue prior to generation of heat is intolerable, producing gross tissue necrosis. Percutaneous cooling of hot implants during the post-operative healing period is a feasible technique, but our current plutonium heat source implant design has been proven of inadequate size and a new design is described. Rough calculations based on tissue conductivity and conductance values suggest that even with this larger device, added heat to proximate tissues may produce long-term changes even though the heat burden may be tolerable over relatively short periods

Transitions to improved core electron heat confinement triggered by low order rational magnetic surfaces in the stellarator TJ-II

International Nuclear Information System (INIS)

Estrada, T.; Medina, F.; Lopez-Bruna, D.; AscasIbar, E.; BalbIn, R.; Cappa, A.; Castejon, F.; Eguilior, S.; Fernandez, A.; Guasp, J.; Hidalgo, C.; Petrov, S.

2007-01-01

Transitions to improved core electron heat confinement are triggered by low order rational magnetic surfaces in TJ-II electron cyclotron heated (ECH) plasmas. Experiments are performed changing the magnetic shear around the rational surface n = 3/m = 2 to study its influence on the transition; ECH power modulation is used to look at transport properties. The improvement in the electron heat confinement shows no obvious dependence on the magnetic shear. Transitions triggered by the rational surface n = 4/m = 2 show, in addition, an increase in the ion temperature synchronized with the increase in the electron temperature. Ion temperature changes had not been previously observed either in TJ-II or in any other helical device. SXR measurements demonstrate that, under certain circumstances, the rational surface positioned inside the plasma core region precedes and provides a trigger for the transition

Additional heating experiments of FRC plasmas

International Nuclear Information System (INIS)

Okada, S.; Asai, T.; Kodera, F.; Kitano, K.; Suzuki, T.; Yamanaka, K.; Kanki, T.; Inomoto, M.; Yoshimura, S.; Okubo, M.; Sugimoto, S.; Ohi, S.; Goto, S.

2001-01-01

Additional heating experiments of neutral beam (NB) injection and application of low frequency wave on a plasma with extremely high averaged beta value of about 90% - a field reversed configuration (FRC) plasma - are carried out on the FRC Injection experiment (FIX) apparatus. These experiments are made possible by translating the FRC plasma produced in a formation region of a theta pinch to a confinement region in order to secure better accessibility to heating facilities and to control plasma density. By appropriate choice of injection geometry and the mirror ratio of the confinement region, the NB with the energy of 14keV and the current of 23A is enabled to be injected into the FRC in the solenoidal confining field of only 0.04-0.05T. Confinement is improved by this experiment. Ion heating is observed by the application of low frequency (80kHz ; about 1/4 of the ion gyro frequency) compressional wave. A shear wave, probably mode converted from the compressional wave, is detected to propagate axially. (author)

Improved damp heat stability of Ga-Doped ZnO thin film by pretreatment of the polyethylene terephthalate substrate

Science.gov (United States)

Kim, B. B.; Seo, S. G.; Lim, Y. S.; Choi, H.-S.; Seo, W.-S.; Park, H.-H.

2013-09-01

A study on the damp heat stability of transparent conducting ZnO thin film grown on a polyethylene terephthalate substrate (PET) is reported. By thermal annealing of the PET substrate at 100°C with Ar flow in a vacuum chamber prior to the sputtering growth of Ga-doped ZnO (GZO) thin film, significantly enhanced damp heat stability was achieved at 60°C with a 90% relative humidity. Electrical and structural characterizations of the GZO thin films were carried out and the effects of the pretreatment on the improved damp heat stability are discussed.

Variable electricity and steam from salt, helium and sodium cooled base-load reactors with gas turbines and heat storage - 15115

International Nuclear Information System (INIS)

Forsberg, C.; McDaniel, P.; Zohuri, B.

2015-01-01

Advances in utility natural-gas-fired air-Brayton combed cycle technology is creating the option of coupling salt-, helium-, and sodium-cooled nuclear reactors to Nuclear air-Brayton Combined Cycle (NACC) power systems. NACC may enable a zero-carbon electricity grid and improve nuclear power economics by enabling variable electricity output with base-load nuclear reactor operations. Variable electricity output enables selling more electricity at times of high prices that increases plant revenue. Peak power is achieved using stored heat or auxiliary fuel (natural gas, bio-fuels, hydrogen). A typical NACC cycle includes air compression, heating compressed air using nuclear heat and a heat exchanger, sending air through a turbine to produce electricity, reheating compressed air, sending air through a second turbine, and exhausting to a heat recovery steam generator (HRSG). In the HRSG, warm air produces steam that is used to produce added electricity. For peak power production, auxiliary heat (natural gas, stored heat) is added before the air enters the second turbine to raise air temperatures and power output. Like all combined cycle plants, water cooling requirements are dramatically reduced relative to other power cycles because much of the heat rejection is in the form of hot air. (authors)

Performance of casting aluminum-silicon alloy condensing heating exchanger for gas-fired boiler

Science.gov (United States)

Cao, Weixue; Liu, Fengguo; You, Xue-yi

2018-01-01

Condensing gas boilers are widely used due to their high heat efficiency, which comes from their ability to use the recoverable sensible heat and latent heat in flue gas. The condensed water of the boiler exhaust has strong corrosion effect on the heat exchanger, which restricts the further application of the condensing gas boiler. In recent years, a casting aluminum-silicon alloy (CASA), which boasts good anti-corrosion properties, has been introduced to condensing hot water boilers. In this paper, the heat transfer performance, CO and NOx emission concentrations and CASA corrosion resistance of a heat exchanger are studied by an efficiency bench test of the gas-fired boiler. The experimental results are compared with heat exchangers produced by Honeywell and Beka. The results show that the excess air coefficient has a significant effect on the heat efficiency and CO and NOx emission of the CASA water heater. When the excess air coefficient of the CASA gas boiler is 1.3, the CO and NOx emission concentration of the flue gas satisfies the design requirements, and the heat efficiency of water heater is 90.8%. In addition, with the increase of heat load rate, the heat transfer coefficient of the heat exchanger and the heat efficiency of the water heater are increased. However, when the heat load rate is at 90%, the NOx emission in the exhaust gas is the highest. Furthermore, when the temperature of flue gas is below 57 °C, the condensation of water vapor occurs, and the pH of condensed water is in the 2.5 5.5 range. The study shows that CASA water heater has good corrosion resistance and a high heat efficiency of 88%. Compared with the heat exchangers produced by Honeywell and Beka, there is still much work to do in optimizing and improving the water heater.

Gum Producers Can Improve Quality Of Gum Marketed and Get Higher Prices

Science.gov (United States)

Ralph W. Clements

1979-01-01

Acid waste from over-treatment and old, wornout iron cups have contributed significantly to the generally poor quality of gum marketed. Today producers are reluctant to purchase new cups and gutters and invest up to $1.80 per tree for production when the market price for gum averages 14.54 per pound annually. Guidelines are given for improving the quality by...

NLP model and stochastic multi-start optimization approach for heat exchanger networks

International Nuclear Information System (INIS)

Núñez-Serna, Rosa I.; Zamora, Juan M.

2016-01-01

Highlights: • An NLP model for the optimal design of heat exchanger networks is proposed. • The NLP model is developed from a stage-wise grid diagram representation. • A two-phase stochastic multi-start optimization methodology is utilized. • Improved network designs are obtained with different heat load distributions. • Structural changes and reductions in the number of heat exchangers are produced. - Abstract: Heat exchanger network synthesis methodologies frequently identify good network structures, which nevertheless, might be accompanied by suboptimal values of design variables. The objective of this work is to develop a nonlinear programming (NLP) model and an optimization approach that aim at identifying the best values for intermediate temperatures, sub-stream flow rate fractions, heat loads and areas for a given heat exchanger network topology. The NLP model that minimizes the total annual cost of the network is constructed based on a stage-wise grid diagram representation. To improve the possibilities of obtaining global optimal designs, a two-phase stochastic multi-start optimization algorithm is utilized for the solution of the developed model. The effectiveness of the proposed optimization approach is illustrated with the optimization of two network designs proposed in the literature for two well-known benchmark problems. Results show that from the addressed base network topologies it is possible to achieve improved network designs, with redistributions in exchanger heat loads that lead to reductions in total annual costs. The results also show that the optimization of a given network design sometimes leads to structural simplifications and reductions in the total number of heat exchangers of the network, thereby exposing alternative viable network topologies initially not anticipated.

Plans for improvements to the ATF ECH system

International Nuclear Information System (INIS)

Bigelow, T.S.; Goldfinger, R.C.; Murakami, M.; Schaich, C.R.; Wilgen, J.B.

1993-01-01

The Advanced Toroidal Facility (ATF) stellarator experiment at Oak Ridge National Laboratory (ORNL) uses electron cyclotron waves for plasma formation and heating. Although the existing systems are quite reliable and produce acceptable plasmas, a few deficiencies should be corrected. Therefore, several possible upgrades to the electron cyclotron heating (ECH) systems have been planned. Some of the desirable changes are (1) improving the launcher to make power deposition in the plasma more centralized, (2) improving the gyrotron power waveform monitoring diagnostics, (3) building a high-field launch system for higher density operation at 53-GHz (4) building a separate transmission line for the 35-GHz gyrotron, and (5) installing a higher frequency, higher power (84- or 110-GHz) gyrotron system for improved plasma density and temperature capability. This paper discusses options for these improvements and conceptual designs. (orig.)

Improving the yield from fermentative hydrogen production.

Science.gov (United States)

Kraemer, Jeremy T; Bagley, David M

2007-05-01

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.

Development of heat resistant concrete and its application to concrete casks. Improvement of neutron shielding performance of concrete in high temperature environment

International Nuclear Information System (INIS)

Owaki, Eiji; Hata, Akihito; Sugihara, Yutaka; Shimojo, Jun; Taniuchi, Hiroaki; Mantani, Kenichi

2003-01-01

Heat resistant concrete with hydrogen, which is able to shield neutron at more than 100degC, was developed. Using this new type concrete, a safety concrete cask having the same concept of metal casks was designed and produced. The new type cask omitted the inhalation and exhaust vent of the conventional type concrete casks. The new concrete consists of Portland cement added calcium hydroxide, iron powder and iron fiber. It showed 2.17 g/cm 3 density, 10.8 mass% water content, 1.4 W/(m·K) thermal conductivity at 150degC. Increasing of heat resistance made possible to produce the perfect sealing type structure, which had high shielding performance of radiation no consideration for streaming of radiation. Moreover, a monitor of sealing can be set. General view of concrete casks, outer view of 1/3 scaled model, cask storage system in the world, properties of new developed heat resistant concrete, results of shielding calculation are contained. (S.Y.)

Comparative Evaluation of Marginal Adaptation and Fracture Strength of Different Ceramic Inlays Produced by CEREC Omnicam and Heat-Pressed Technique

OpenAIRE

Oz, F. D.; Bolay, S.

2018-01-01

Objective. The aim of this in vitro study was to evaluate marginal adaptation and fracture strength of inlays produced by CEREC Omnicam using different types of blocs and heat-pressed technique. Methods: Seventy-five extracted human mandibular molars were divided randomly into 5 groups (n=15). 60 molars in four groups received MOD inlay preparations. Experimental groups were CO: Intact teeth, EC: IPS e.max CAD and CEREC, LU: Lava Ultimate and CEREC, EL: IPS Empress CAD and CEREC, EP: IPS Empr...

Nuclear heat source design for an advanced HTGR process heat plant

International Nuclear Information System (INIS)

McDonald, C.F.; O'Hanlon, T.W.

1983-01-01

A high-temperature gas-cooled reactor (HTGR) coupled with a chemical process facility could produce synthetic fuels (i.e., oil, gasoline, aviation fuel, methanol, hydrogen, etc.) in the long term using low-grade carbon sources (e.g., coal, oil shale, etc.). The ultimate high-temperature capability of an advanced HTGR variant is being studied for nuclear process heat. This paper discusses a process heat plant with a 2240-MW(t) nuclear heat source, a reactor outlet temperature of 950 0 C, and a direct reforming process. The nuclear heat source outputs principally hydrogen-rich synthesis gas that can be used as a feedstock for synthetic fuel production. This paper emphasizes the design of the nuclear heat source and discusses the major components and a deployment strategy to realize an advanced HTGR process heat plant concept

Greenhouse cooling and heat recovery using fine wire heat exchangers in a closed pot plant greenhouse: design of an energy producing greenhouse

NARCIS (Netherlands)

Bakker, J.C.; Zwart, de H.F.; Campen, J.B.

2006-01-01

A greenhouse cooling system with heat storage for completely closed greenhouses has been designed, based on the use of a fine wire heat exchanger. The performance of the fine wire heat exchangers was tested under laboratory conditions and in a small greenhouse compartment. The effects of the system

Improvement in ductility of high strength polycrystalline Ni-rich Ni{sub 3}Al alloy produced by EB-PVD

Energy Technology Data Exchange (ETDEWEB)

Sun, J.Y.; Pei, Y.L.; Li, S.S.; Zhang, H.; Gong, S.K., E-mail: gongsk@buaa.edu.cn

2014-11-25

Highlights: • High strength and high ductility of polycrystalline Ni-rich Ni{sub 3}Al alloy sheets were produced. • The elongation could be enhanced from ∼0.5% to ∼14.6% by microstructural control. • The fracture strength (∼820 MPa) was enhanced by the precipitation strengthening. • This work provides a general processing for repairing the worn single crystal blades. - Abstract: A 300 μm Ni-rich Ni{sub 3}Al sheet was produced by electron beam physical vapor deposition (EB-PVD) and followed by different heat treatments to obtain fine γ′/γ two-phase structures with large elongation. Tensile testing was performed at room-temperature, and the corresponding mechanisms were investigated in detail. Results indicated that the as-deposited Ni{sub 3}Al alloy exhibited non-equilibrium directional columnar crystal, and transited to equiaxed crystal with uniformly distributed tough γ phase after heat treatment. Meanwhile, the fracture mechanism transited from brittleness to a mixture of ductility and brittleness modes. With an appropriate heat treatment, high strength (ultimate tensile strength obtained 828 MPa) and high ductility (elongation obtained 14.6%) Ni{sub 3}Al alloy has been achieved, which was due to the mesh network microstructure. A series of transmission electron microscope (TEM) characterizations confirmed that the increasing flow stress of Ni{sub 3}Al alloy was attributed to the cubical secondary γ′ phase precipitates (25–50 nm) within the γ phase. This work provides a potential strategy for repairing the worn tip of single crystal engine blades using Ni-rich Ni{sub 3}Al alloy by EB-PVD.

Load Management in District Heating Operation

OpenAIRE

Li, Hongwei; Wang, Stephen Jia

2015-01-01

Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensuresecurity of supply during severe heating seasons. The peak heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance withoutjeopardizing the consumer thermal co...

Sleeving repair of heat exchanger tubes

International Nuclear Information System (INIS)

Street, Michael D.; Schafer, Bruce W.

2000-01-01

Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat

Nanoscale heat transfer in carbon nanotube - sugar alcohol composites as heat storage materials

NARCIS (Netherlands)

Zhang, H.; Rindt, C.C.M.; Smeulders, D.M.J.; Gaastra - Nedea, S.V.

2016-01-01

Nanoscale carbon structures such as graphene and carbon nanotubes (CNTs) can greatly improve the effective thermal conductivity of thermally sluggish heat storage materials, such as sugar alcohols (SAs). The specific improvement depends on the heat transfer rate across the carbon structure. Besides,

Neck-cooling improves repeated sprint performance in the heat

Directory of Open Access Journals (Sweden)

Caroline eSunderland

2015-11-01

Full Text Available The present study evaluated the effect of neck-cooling during exercise on repeated sprint ability in a hot environment. Seven team-sport playing males completed two experimental trials involving repeated sprint exercise (5 x 6 s before and after two 45 min bouts of a football specific intermittent treadmill protocol in the heat (33.0  0.2 ºC; 53 ± 2% relative humidity. Participants wore a neck-cooling collar in one of the trials (CC. Mean power output and peak power output declined over time in both trials but were higher in CC (540 ± 99 v 507 ± 122W, d = 0.32; 719 ± 158 v 680 ± 182 W, d = 0.24 respectively. The improved power output was particularly pronounced (d = 0.51 – 0.88 after the 2nd 45 min bout but the CC had no effect on % fatigue. The collar lowered neck temperature and the thermal sensation of the neck (P 0.05. There were no trial differences but interaction effects were demonstrated for prolactin concentration and rating of perceived exertion (RPE. Prolactin concentration was initially higher in the collar cold trial and then was lower from 45 minutes onwards (interaction trial x time P=0.04. RPE was lower during the football intermittent treadmill protocol in the collar cold trial (interaction trial x time P = 0.01. Neck-cooling during exercise improves repeated sprint performance in a hot environment without altering physiological or neuroendocrinological responses. RPE is reduced and may partially explain the performance improvement.

Comparison of tubeside condensation and evaporation characteristics of smooth and enhanced heat transfer 1EHT tubes

International Nuclear Information System (INIS)

Kukulka, David J.; Smith, Rick; Li, Wei

2015-01-01

Results are presented here from an experimental investigation that was performed to evaluate the inside condensation and evaporation heat transfer of R410A, R22 and R32 that took place in a 12.7 mm (0.5 in) O.D. horizontal copper tube at low mass fluxes. Tubes considered in this evaluation consisted of a smooth tube (inner diameter 11.43 mm) and a newly developed enhanced surface Vipertex™ 1EHT tube. Heat transfer enhancement is an important factor in obtaining energy efficiency improvements in a variety of heat transfer applications. Utilization of enhanced heat transfer tubes is often utilized in the development of high performance air conditioning and refrigeration systems. Vipertex™ has designed and produced these surfaces through three dimensional material surface modifications which produces flow optimized, enhanced heat transfer tubes that increase heat transfer. Heat transfer enhancement plays an important role in improving energy efficiencies and developing high performance thermal systems. This study details the evaluation of the in-tube evaporation and condensation that takes place in these tubes over a wide range of conditions. The test apparatus utilized included a straight horizontal test section with an active length heated by water circulated in the surrounding annulus. Constant heat flux was maintained and refrigerant quality varied. In-tube evaporation measurements of R22, R32 and R410A are reported for evaporation at 10 °C with mass flow rates in the range of 15–40 kg h"−"1. Single phase measurements are reported for mass flow rates from 15 kg h"−"1 to 80 kg h"−"1. Condensation tests were conducted at a saturation temperature of 47 °C, with an inlet quality of 0.8 and an outlet quality of 0.1. In a comparison to smooth tubes, the average heat transfer coefficients for the Vipertex 1EHT tube exceeded those of a smooth tube. Average evaporation and condensation heat transfer coefficients for R22, R32 and R410A in the 1EHT

Using AlN-Coated Heat Sink to Improve the Heat Dissipation of LED Packages

Directory of Open Access Journals (Sweden)

Jean Ming-Der

2016-01-01

Full Text Available This study optimizes aluminum nitride (AlN ceramics, in order to enhance the thermal performance of light-emitting diode (LED packages. AlN coatings are grown on copper/ aluminum substrates as a heat interface material, using an electrostatic spraying process. The effect of the deposition parameters on the coatings is determined. The thermal performance of AlN coated Cu/Al substrates is evaluated in terms of the heat dissipated and compared by measuring the LED case temperature. The structure and properties of the coating are also examined a scanning electron microscopy (SEM. In sum, the thermal performance of the LED is increased and good heat resistance characteristics are obtained. The results show that using AlN ceramic coating on a copper/aluminum substrate increases the thermal performance.

A high performance cocurrent-flow heat pipe for heat recovery applications

Science.gov (United States)

Saaski, E. W.; Hartl, J. C.

1980-01-01

By the introduction of a plate-and-tube separator assembly into a heat pipe vapor core, it has been demonstrated that axial transport capacity in reflux mode can be improved by up to a factor of 10. This improvement is largely the result of eliminating the countercurrent shear that commonly limits reflux heat pipe axial capacity. With benzene, axial heat fluxes up to 1800 W/sq cm were obtained in the temperature range 40 to 80 C, while heat flux densities up to 3000 W/sq cm were obtained with R-11 over the temperature range 40 to 80 C. These very high axial capacities compare favorably with liquid metal limits; the sonic limit for liquid sodium, for example, is 3000 W/sq cm at 657 C. Computational models developed for these cocurrent flow heat pipes agreed with experimental data within + or - 25%.

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

Urban Heat Wave Hazard Assessment

Science.gov (United States)

Quattrochi, D. A.; Jedlovec, G.; Crane, D. L.; Meyer, P. J.; LaFontaine, F.

2016-12-01

Heat waves are one of the largest causes of environmentally-related deaths globally and are likely to become more numerous as a result of climate change. The intensification of heat waves by the urban heat island effect and elevated humidity, combined with urban demographics, are key elements leading to these disasters. Better warning of the potential hazards may help lower risks associated with heat waves. Moderate resolution thermal data from NASA satellites is used to derive high spatial resolution estimates of apparent temperature (heat index) over urban regions. These data, combined with demographic data, are used to produce a daily heat hazard/risk map for selected cities. MODIS data are used to derive daily composite maximum and minimum land surface temperature (LST) fields to represent the amplitude of the diurnal temperature cycle and identify extreme heat days. Compositing routines are used to generate representative daily maximum and minimum LSTs for the urban environment. The limited effect of relative humidity on the apparent temperature (typically 10-15%) allows for the use of modeled moisture fields to convert LST to apparent temperature without loss of spatial variability. The daily max/min apparent temperature fields are used to identify abnormally extreme heat days relative to climatological values in order to produce a heat wave hazard map. Reference to climatological values normalizes the hazard for a particular region (e.g., the impact of an extreme heat day). A heat wave hazard map has been produced for several case study periods and then computed on a quasi-operational basis during the summer of 2016 for Atlanta, GA, Chicago, IL, St. Louis, MO, and Huntsville, AL. A hazard does not become a risk until someone or something is exposed to that hazard at a level that might do harm. Demographic information is used to assess the urban risk associated with the heat wave hazard. Collectively, the heat wave hazard product can warn people in urban

Heat transfer from two-side heated helical channels

International Nuclear Information System (INIS)

Shimonis, V.; Ragaishis, V.; Poshkas, P.

1995-01-01

Experimental results are presented on the heat transfer from two-side heated helical channels to gas (air) flows. The study covered six configurations and wide ranges of geometrical (D/h=5.5 to 84.2) and performance (Re=10 3 to 2*10 5 ) parameters. Under the influence of Re and of the channel curvature, the heat transfer from both the convex and the concave surfaces for two-side heating (q w1 ≅ q w2 ) is augmented by 20-30% over one-side heating. Improved relations to predict the critical values of Reynolds Re cr1 and Re cr2 are suggested. They enable more exact predictions of the heat transfer from convex surface in transient flows for one-side heating. The relation for annular channels is suggested for the turbulent heat transfer from the convex and concave surfaces of two-side heated helical channels. It can be adapted by introducing earlier expresions for one-side heated helical channels. (author). 6 refs., 2 tabs., 3 figs

Chronic heat improves mechanical and metabolic response of trained rat heart on ischemia and reperfusion.

Science.gov (United States)

Levy, E; Hasin, Y; Navon, G; Horowitz, M

1997-05-01

Cardiac mechanics and metabolic performance were studied in isolated perfused hearts of rats subjected to a combined chronic stress of heat acclimation and swimming training (EXAC) or swimming training alone (EX). Diastolic (DP) and systolic pressures (SP), coronary flow (CF), and oxygen consumption were measured during normoperfusion (80 mmHg), and the appearance of ischemic contracture (IC), DP, and SP were measured during progressive graded ischemia, total ischemia (TI), and reperfusion insults. ATP, phosphocreatine, and intracellular pH were measured during TI and reperfusion with 31P nuclear magnetic resonance spectroscopy. During normoperfusion, SP and cardiac efficiency (derived from rate-pressure product-oxygen consumption relationships) were the highest in the 2-mo EXAC hearts (P pool and there was a delayed decline in intracellular pH. On reperfusion, these hearts also displayed improved ATP and phosphocreatine recovery, the 2-mo EXAC heart demonstrating significantly faster high-energy phosphate salvage, improved diastolic function, and pulse pressure recovery. The data attest to the beneficial effects of heat acclimation on cardiac mechanics of trained rats during normoperfusion and cardiac protection on ischemia and reperfusion. Possibly, energy sparing, lesser acidosis, and shorter duration of IC on ischemia and improved energy salvage on reperfusion contribute synergistically to this potent beneficial effect.

An assessment tool to help producers improve cow comfort on their farms.