WorldWideScience

Sample records for areas heat shinku

  1. Comprehensive assessments of measures mitigating heat island phenomena in urban areas; Heat shinku wo riyoshita daikibo reibo system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, T.; Yamamoto, S.; Yoshikado, H.; Kondo, H.; Kaneho, N.; Saegusa, N.; Inaba, A. [National Institute for Resources and Environment, Tsukuba (Japan); Inoue, M. [New Energy and Industrial Technology Development Organization, Tokyo, (Japan)

    1997-02-01

    This paper describes the assessment method of measures mitigating heat island phenomena in urban areas. The heat island phenomena were classified into meso-scale with 100 km-scale, block-scale with several km-scale, and building-scale with 100 m-scale. Urban thermal environment simulation model was developed in response to each scale. For the development, regional data using aircraft and artificial satellite observations, surface observation and thermal environment observation at Shinjuku new central city of Tokyo, and artificial waste heat actual survey data in the southern Kanto district were utilized. Results of the urban thermal environment simulation were introduced as an application of this model. Temperature distributions of the heat island in the Kanto district were simulated with considering urban conditions near Tokyo and without considering it. Daily changes of wall surfaces of high buildings and road surface were calculated. Increase in the air temperature in the back stream of building roofs with increased temperature was determined. 4 figs.

  2. Comprehensive assessments of measures mitigating heat island phenomena in urban areas; Heat shinku wo riyoshita daikibo reibo system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishitani, H.; Yamada, K.; Yamaji, K.; Matsuhashi, T.; Iizuka, E.; Suzuki, T.; Genchi, H.; Komiyama, H. [The University of Tokyo, Tokyo (Japan)

    1997-02-01

    This paper describes actual condition and measures against heat island (HI) phenomena in large urban areas with buildings. Tokyo was selected as a model. To extract typical pattern of daily change of air temperature, statistic analysis was conducted using the existing air temperature data at 100 points in and near the city of Tokyo. As a result, five patterns were obtained, i.e., central city, sea/land water affecting zone, thickly settled suburbs, garden city, and countryside. Each one point was selected in each pattern, to measure the underground temperature. It was found that the effect of HI can be easily evaluated from the underground temperature. It was suggested that the HI effect in the central city is estimated to be around 3.6 {degree}C. The measures mitigating HI were divided into the thermal balance improvement in the whole district and the temperature improvement of living space by homogenization or inhomogenization. Energy conservation was investigated for improving the thermal balance which can be practically conducted. According to the measures, it was found that the air temperature in the central city can be decreased by about 0.5 {degree}C at maximum. 3 figs., 1 tab.

  3. Heat transfer from oriented heat exchange areas

    Science.gov (United States)

    Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej

    2014-03-01

    This paper deals with the transfer of heat-driven heat transfer surface area in relation to the construction of the criterion equation for "n" horizontal pipe one about another. On the bases of theoretical models have been developed for calculating the thermal performance of natural convection by Churilla and Morgan, for various pipe diameters and temperatures. These models were compared with models created in CFD-Fluent Ansys the same boundary conditions. The aim of the analyse of heat and fluxional pipe fields "n" pipes one about another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. At presence a sum of criterion equations exists for simple geometrical shapes of individual oriented geometrical areas but the criterion equation which would consider interaction of fluxional field generated by free convection from multiple oriented areas is not mentioned in standardly accessible technical literature and other magazine publications.

  4. Entanglement area law from specific heat capacity

    CERN Document Server

    Brandao, Fernando G S L

    2014-01-01

    We study the scaling of entanglement in low-energy states of quantum many-body lattice models in arbitrary dimensions. We show that if at low enough temperatures the specific heat capacity of the model decays exponentially with inverse temperature, the entanglement in every low-energy state satisfies an area law (with a logarithmic correction). This behaviour of the heat capacity is typically observed in gapped systems. Assuming merely that the low-temperature specific heat decays polynomially with temperature, we find a subvolume scaling of entanglement. Our results give experimentally verifiable conditions for area laws, and show that they are a generic property of low-energy states of matter.

  5. Mapping Heat Health Risks in Urban Areas

    Directory of Open Access Journals (Sweden)

    Margaret Loughnan

    2012-01-01

    Full Text Available Periods of extreme heat pose a risk to the health of individuals, especially the elderly, the very young, and the chronically ill. Risk factors include housing characteristics, and socioeconomic factors, or environmental risk factors such as urban heat islands. This study developed an index of population vulnerability in an urban setting using known environmental, demographic, and health-related risk factors for heat stress. The spatial variations in risk factors were correlated with spatial variation in heat-related health outcomes in urban Melbourne. The index was weighted using measured health outcomes during heatwave periods. The index was then mapped to produce a spatial representation of risk. The key risk factors were identified as areas with aged care facilities, higher proportions of older people living alone, living in suburban rather than inner city areas, and areas with larger proportions of people who spoke a language other than English at home. The maps of spatial vulnerability provide information to target heat-related health risks by aiding policy advisors, urban planners, healthcare professionals, and ancillary services to develop heatwave preparedness plans at a local scale.

  6. Future Heat Waves in Paris Metropolitan Area

    Science.gov (United States)

    Beaulant, A.; Lemonsu, A.; Somot, S.; Masson, V.

    2010-12-01

    Cities are particularly vulnerable to heat waves, firstly because they concentrate the majority of the population and, secondly because the heat island that characterizes the urban climate exacerbates heat wave effects. This work is part of the interdisciplinary VURCA project (Vulnerability of cities to heat waves), which deals with the evolution of heat wave events in the context of global warming, urban vulnerability and adaptation strategies. The aim of this study is to analyse urban heat wave events in present climate (1950-2009) and their evolution in an enhanced greenhouse gazes future climate (2010-2100). We used daily observations of temperature from several stations covering Paris metropolitan area and climate projections following three different IPCC-SRES scenarios (B1, A1B, A2) and issued from several ENSEMBLES regional climate models. The heat wave definition is based on the indexes of the operational French warning system. A heat wave is detected within observed or simulated time-series by a heat wave peak, when the temperatures exceed the value of the 99.9th percentile. Its duration is determined by all adjacent days to this peak, for which the temperatures are not durably smaller than the 99.9th percentile value minus 2 °C. The 99.9th percentile threshold is inferred from quantile-quantile plots produced for each climate model in comparison with observations for the reference period 1950-2000. Heat waves have been extracted within observations and 12 climatic simulations. The number of heat wave events and cumulated HW days per year have been calculated, the maximum being seven heat waves cumulating more than 60 HW days in one year in the case of the A2 scenario and until 50 days in the case of the more moderate A1B scenario. From 2050, the occurrence of three or four HW events per year is becoming the norm all scenarios taken together. The evolution of heat wave features has been analysed, highlighting the large variability of the climatic

  7. Mapping Heat Health Risks in Urban Areas

    OpenAIRE

    Margaret Loughnan; Neville Nicholls; Tapper, Nigel J.

    2012-01-01

    Periods of extreme heat pose a risk to the health of individuals, especially the elderly, the very young, and the chronically ill. Risk factors include housing characteristics, and socioeconomic factors, or environmental risk factors such as urban heat islands. This study developed an index of population vulnerability in an urban setting using known environmental, demographic, and health-related risk factors for heat stress. The spatial variations in risk factors were correlated with spatial ...

  8. Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings: A case study of the Copenhagen district heating area in Denmark

    International Nuclear Information System (INIS)

    The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized heating plants that are too expensive to build in comparison with the potential energy savings in buildings. Long-term strategies for the existing building stock must ensure that costs are minimized and that investments in energy savings and new heating capacity are optimized and carried out at the right time. - Highlights: • We investigate how much heating consumption needs to be reduced in a district heating area. • We examine fossil-fuel-free supply vs. energy conservations in the building stock. • It is slightly cost-beneficial to invest in energy renovation from today for a societal point of view. • It is economically beneficial for district heating companies to invest in energy renovations from today. • The cost per delivered heat unit is lower when energy renovations are carried out from today

  9. Note: Anodic bonding with cooling of heat-sensitive areas

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; Olsen, Jakob Lind; Henriksen, Toke Riishøj;

    2010-01-01

    Anodic bonding of silicon to glass always involves heating the glass and device to high temperatures so that cations become mobile in the electric field. We present a simple way of bonding thin silicon samples to borosilicate glass by means of heating from the glass side while locally cooling heat......-sensitive areas from the silicon side. Despite the high thermal conductivity of silicon, this method allows a strong anodic bond to form just millimeters away from areas essentially at room temperature....

  10. Long-term impacts of heat demand reductions within the Aarhus district heating area

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    in the expected production facilities of 2016 and the implementation of heat savings in three different scenarios, where heat savings of 50% are carried out gradually until 2050. The costs in all scenarios are compared though net present value calculations based on socio-economic costs. The results show...... the current heat price that is taken into account. Often the long-term costs are not reflected in the heat price and since the benefits of investing in heat saving measures last for a long time, the decision should be based on long-term planning taking reinvestments in production capacity and distribution...... is decided on the basis of short-term decisions based on the payback time of the investments compared to the current heat price. Since a large share of the Danish buildings are within district heating areas with a low marginal heat price, heat saving measures have a long payback time if it is only...

  11. Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings

    DEFF Research Database (Denmark)

    Harrestrup, Maria; Svendsen, S.

    2014-01-01

    the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper...... is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized......The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce...

  12. District Heating in Areas with Low Energy Houses

    DEFF Research Database (Denmark)

    Tol, Hakan Ibrahim

    This PhD thesis presents a summary of a three-year PhD project involving three case studies, each pertaining to a typical regional Danish energy planning scheme with regard to the extensive use of low-energy district heating systems, operating at temperatures as low as 55°C for supply and 25°C...... for return, and with the aim of intensive exploitation of renewable energy sources. The hypothesis is that a detailed analysis of energy performance and cost of construction and operation of low energy district heating systems can be used as a rational basis for planning use of district heating in areas...... with low energy houses. The first case study focus was concerned with developing a method for the designing of low-energy district heating systems for new settlements in which low-energy houses were to be built. The method involved primarily the development of a novel pipe dimensioning method based...

  13. Exergetic Optimization of the Heat Recovery Steam Generators by Imposing the Total Heat Transfer Area

    OpenAIRE

    Cenuşă, Victor-Eduard; Feidt, Michel; Badea, Adrian; Benelmir, Riad

    2004-01-01

    The paper presents an original and fast method for the heat recovery steam generator (HRSG) exergetic optimization. The objective is maximizing the exergy transfer to the water / steam circuit. The proposed approach, different from the classical method that fixes the pinch point, is essentially thermodynamic but it considers also the economics by imposing the total heat transfer area of HRSG. The HRSG may have one or two steam pressures, without reheat. The input data from the gas turbine are...

  14. Urban heat evolution in a tropical area utilizing Landsat imagery

    Science.gov (United States)

    Amanollahi, Jamil; Tzanis, Chris; Ramli, Mohammad Firuz; Abdullah, Ahmad Makmom

    2016-01-01

    Cloud cover is the main limitation of using remote sensing to study Land Use and Land Cover (LULC) change, and Land Surface Temperature (LST) in tropical area like Malaysia. In order to study LULC change and its effect on LST, the Landsat images were utilized within Geographical Information System (GIS) with the aim of removing the effect of cloud cover and image's gaps on the Digital Number (DN) of the pixels. 5356 points according to pixels coordinate which represent the 960 m to 960 m area were created in GIS environment and matched with thermal bands of the study area in remote sensing environment. The DNs of these points were processed to extract LST and imported in GIS environment to derive the temperature maps. Temperature was found to be generally higher in 2010 than in 2000. The comparison of the highest temperature area in the temperature maps with ground stations data showed that the topographical characteristics of the area, and the wind speed, and direction influence the occurrence of Urban Heat Island (UHI) effect. This study concludes that integration of remote sensing data and GIS is a useful tool in urban LST detection in tropical area.

  15. Scaling Flux Tower Observations of Sensible Heat Flux Using Weighted Area-to-Area Regression Kriging

    Directory of Open Access Journals (Sweden)

    Maogui Hu

    2015-07-01

    Full Text Available Sensible heat flux (H plays an important role in characterizations of land surface water and heat balance. There are various types of H measurement methods that depend on observation scale, from local-area-scale eddy covariance (EC to regional-scale large aperture scintillometer (LAS and remote sensing (RS products. However, methods of converting one H scale to another to validate RS products are still open for question. A previous area-to-area regression kriging-based scaling method performed well in converting EC-scale H to LAS-scale H. However, the method does not consider the path-weighting function in the EC- to LAS-scale kriging with the regression residue, which inevitably brought about a bias estimation. In this study, a weighted area-to-area regression kriging (WATA RK model is proposed to convert EC-scale H to LAS-scale H. It involves path-weighting functions of EC and LAS source areas in both regression and area kriging stages. Results show that WATA RK outperforms traditional methods in most cases, improving estimation accuracy. The method is considered to provide an efficient validation of RS H flux products.

  16. Exergetic Optimization of the Heat Recovery Steam Generators by Imposing the Total Heat Transfer Area

    Directory of Open Access Journals (Sweden)

    Michel Feidt

    2004-09-01

    Full Text Available The paper presents an original and fast method for the heat recovery steam generator (HRSG exergetic optimization. The objective is maximizing the exergy transfer to the water / steam circuit. The proposed approach, different from the classical method that fixes the pinch point, is essentially thermodynamic but it considers also the economics by imposing the total heat transfer area of HRSG. The HRSG may have one or two steam pressures, without reheat. The input data from the gas turbine are: the mass flow rate, the temperature and the molar composition of flue gases. The results are the optimum pressures of the superheated steam. The numerical computations were realized in Delphi programming utility. The obtained results are in agreement with the recent literature.

  17. Temperature patterns in the gas infrared radiator heating area

    Directory of Open Access Journals (Sweden)

    Kurilenko N.I.

    2015-01-01

    Full Text Available The obtained results of experimental studies provide the basis for the heat transfer mechanism specification on the studied conditions that are typical for many practical applications. It was proved appropriateness of the natural convection and heat conduction process simulation while analyzing the heat transfer in rectangular enclosures with the radiant heating sources at the high bound.

  18. Minimizing investment cost for multi-period heat exchanger network retrofit by matching heat transfer areas with different strategies

    Institute of Scientific and Technical Information of China (English)

    Lixia Kang; Yongzhong Liu

    2015-01-01

    Multi-period heat exchanger network (HEN) retrofit is usually performed by targeting and matching heat trans-fer areas. In this paper, based on the reverse order matching method we proposed previously, three strategies of matching heat transfer areas are proposed to minimize the investment cost for the retrofit of HEN in multi-period, in which replacement of heat exchangers, addition of heat exchangers and addition of heat transfer areas are performed. We demonstrate the procedures through three scenarios, including maximum number of substituted heat exchangers after retrofit, minimum additional heat transfer areas in the retrofitted HEN, and minimum investment cost for retrofit. The strategies are extended to a single period HEN retrofit problem. The results of multi-period and single period HEN retrofit problems indicate the effectiveness of the strategies. More-over, these results are better than those reported in literature. The strategies are simple and easy to implement, which are of great benefit to large-scale HEN retrofit in practice.

  19. District heating supply for low energy areas. second edition; Fjernvarmeforsyning af lavenergiomraeder. 2 udgave

    Energy Technology Data Exchange (ETDEWEB)

    Kristjansson, H.; Buus, F. [Carl Bro as, Glostrup (Denmark); Boehm, B.; Vejen, N.K. [Danmarks Tekniske Univ., Kgs. Lyngby (Denmark); Rasmussen, J. [Star Pipe, Fredericia (Denmark); Paaske Christensen, K. [Nykoebing Falster Kommune, Nykoebing Falster (Denmark); Bidstrup, N. [Grundfos A/S, Broendby (Denmark)

    2004-08-01

    This report presents recommendations for design of district heating distribution systems in low energy buildings or in other areas with low heating density. For a joint heat supply of areas with low heat density distribution costs are high compared to heat sale. At the same time district heating flow pipes and pumps have developed significantly during the last decade. The project aims at identifying the optimal district heating distribution design for these conditions. The optimal design is dependent on heat price, price level and economic timeframe. Furthermore, savings are dependent of choice of frame of reference. Conditions can vary significantly from one area to another, but preconditions have been adapted to a reasonable level. (BA)

  20. The potential to supply low temperature district heating to existing building area

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2013-01-01

    Low-temperature district heating (LTDH) has the advantages as reduced network heat loss, improved quality match between energy supply and energy demand, and increased utilization of low-grade waste heat and renewable energy. The LTDH represents the next generation district heating (DH) system...... to supply existing building areas which are characterized with high heating demand needs to be examined. In this paper, the DH network deliverable capacity to supply LTDH to an existing building area is studied based on building thermal performance and DH network hydraulic performance simulation....

  1. Electricity demand profile with high penetration of heat pumps in Nordic area

    DEFF Research Database (Denmark)

    Liu, Zhaoxi; Wu, Qiuwei; Nielsen, Arne Hejde;

    2013-01-01

    This paper presents the heat pump (HP) demand profile with high HP penetration in the Nordic area in order to achieve the carbon neutrality power system. The calculation method in the European Standard EN14825 was used to estimate the HP electricity demand profile. The study results show...... there will be high power demand from HPs and the selection of supplemental heating for heat pumps has a big impact on the peak electrical power load of heating. The study in this paper gives an estimate of the scale of the electricity demand with high penetration of heat pumps in the Nordic area....

  2. Full Scale Investigation of the Dynamic Heat Storage of Concrete Decks with PCM and Enhanced Heat Transfer Surface Area

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...... can result in the increased heat amount that can be transferred and stored in the heavy construction element during the diurnal indoor temperature fluctuations.......The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...

  3. Climate change and heat waves in Paris and London metropolitan areas

    Science.gov (United States)

    Dousset, B.

    2010-12-01

    Summer warming trends in Western and Central Europe and in Mediterranean regions are increasing the incidence, intensity, and duration of heat waves. Those extreme events are especially deadly in large cities, owing to high population densities, surface characteristics, heat island effects, anthropogenic heat and pollutants. In August 2003, a persistent anticyclone over Western Europe generated a heat wave of exceptional strength and duration with an estimated death toll of 70,000, including 4678 in the Paris region. A series of NOAA-AVHRR satellite thermal images over the Paris and London metropolitan areas, were used to analyze Land Surface Temperature (LST) and its related mortality. In the Paris region, LSTs were merged with land use and cover data to identify risk areas, and thermal indicators were produced at the addresses of ~ 500 elderly people to assess diurnal heat exposure. Results indicate: (i) contrasting night time and daytime heat island patterns related to land use and surface characteristics; (ii) the relation between night-time heat islands and heat waves intensity; (iii) the impact of elevated minimal temperatures on excess mortality, with a 0.5 °C increase doubling the risk of death, (in the temperature range of the heatwave); iv) the correlation between the spatial distribution of highest night-time LSTs and that of highest mortality ratios; and v) the significant impact of urban parks in the partitioning between latent and sensible surface heat fluxes, despite a prior warm and dry spring. Near-real time satellite monitoring of heat waves in urban areas improve our understanding of the LST processes and spatial variability, and of the related heat stress and mortality. These observations provide criteria for warning systems, contingency policies and planning, and climate adaptation and mitigation strategies.

  4. Technical and economical analysis of concepts for using the heat of biogas plants in rural areas

    International Nuclear Information System (INIS)

    Since the implementation of the EEG in Germany the biogas production becomes an independent branch of industry in the agriculture. At this time more than 90 percent of the biogas plants work with co-generation plant for heat and power with a thermal engine efficiencies of more than 50 percent. Because of the location in the rural area heat costumers with a continuous demand of heat over the whole year are rare. This research had a closer look how to use the heat of biogas production efficiently and also generating profit. The aim of the study was to use heat over the whole year, a profitable heat concept without counting the KWK-bonus and an added value on the farm. During the study the following concepts were analyzed: asparagus production using soil heating, drying equipment for different products, the production of fish in aquaculture, the poultry production and the heated production of tomatoes. The results showed different concepts using heat of biogas plants as efficient for farmers. However with only one concept the aims - to use the heat over the whole year, generating a profitable heat concept without counting the KWK-bonus, add an value on the farm - mostly can not be achieved. The combination of different heat concepts is necessary. In this analysis the poultry production in combination with the dryer can be considered as the most efficient concept. Bearing in mind the benefit which can be generated with a heat concept as well as the higher income and the higher technical efficiency of biogas plants operators should implement an individual concept for their heat.

  5. The Discuss of the Heat Allocation by Heating Time and Heating Area%时间面积通断法进行热计量探讨

    Institute of Scientific and Technical Information of China (English)

    孙丽婧; 侯宇; 宋平

    2012-01-01

    时间面积通断法作为一种有效的热计量手段已经逐渐被接受,其热计量的公平性已比其他热计量方法改进不少,但仍有值得改进的地方。本文根据典型住宅户间传热的模拟计算,认为完全以用热量为计量标准,不能完全反映出热量的实际使用情况,同时根据计算情况,给出了按住房面积分摊热费和以实际用热量分摊热费的比例。%As an effective method of heat allocation by heating time and heating area, it has come to be widely accepted. The faimess of the method has improved a lot than many other thermal measurements, but it is still worth of improvement. This article based on a typical residential simulation of the heat transfer between adjacent rooms, considered to be entirely to measure the use of heat cannot fully reflect the actual use of the heat. This article also gives the ratio of sharing housing costs and the actual use of thermal energy heating cost.

  6. Excess heat production of future net zero energy buildings within district heating areas in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    2012-01-01

    Denmark’s long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and netzeroenergybuildings (NZEBs) has increased. Most...... buildings in Denmark are connected to electricity grids and around half are connected to districtheating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper’s objective is to examine how excess heat production from NZEBs...

  7. Rapid heat-flowing surveying of geothermal areas, utilizing individual snowfalls as calorimeters

    Science.gov (United States)

    White, Donald E.

    1969-01-01

    Local differences in rate of heat transfer in vapor and by conduction through the ground in hot spring areas are difficult and time-consuming to measure quantitatively. Individual heavy snowfalls provide a rapid low-cost means of measuring total heat flow from such ground. After a favorable snowfall (heavy, brief duration, little wind, air temperature near 0°C), contacts between snow-covered and snow-free ground are mapped on a suitable base. Each mapped contact, as time elapses after a specific snowfall, is a heat-flow contour representing a decreasing rate of flow. Calibration of each mapped contact or snow line is made possible by the fact that snow remains on insulated surfaces (such as the boardwalks of Yellowstone's thermal areas) long after it has melted on adjacent warm ground. Heat-flow contours mapped to date range from 450 to 5500 μcal/cm2 sec, or 300 to 3700 times the world average of conductive heat flow. The very high rates of heat flow (2000 to > 10,000 μcal/cm2 sec) are probably too high, and the lower heat flows determinable by the method (2 sec) may be too low. Values indicated by the method are, however, probably within a factor of 2 of the total conductive and convective heat flow. Thermal anomalies from infrared imagery are similar in shape to heat-flow contours of a test area near Old Faithful geyser. Snowfall calorimetry provides a rapid means for evaluating the imagery and computer-derived products of the infrared data in terms of heat flow.

  8. Heat Mismatch of future Net Zero Energy Buildings within district heating areas in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    The long-term goal for Denmark is to develop an energy system solely based on renewable energy sources (RES) in 2050. To reach this goal energy savings in buildings are essential. Therefore, a focus on energy efficient measures in buildings and net zero energy buildings (NZEBs) have increased...... systems enables them to send or receive energy from these systems. This is beneficial for NZEBs because even though they have an annual net exchange of zero, there is a temporal mismatch in regard to the energy consumption of buildings and the production from the renewable energy units added to them....... NZEBs are characterized by having a greatly reduced energy demand that on an annual basis can be balanced out by an equivalent generation of energy from RES. Most buildings in Denmark are connected electricity grids and around half to district heating (DH) systems. Connecting buildings to larger energy...

  9. Temporal & Spatial Distribution of Extreme Heat Event in NYC Metro-Area

    Science.gov (United States)

    Alvi, M. N.

    2012-12-01

    Recent studies indicate an increase in extreme summer weather events that may be linked to global warming. Heat wave intensity and frequency trends are a relatively unexplored topic that may demonstrate a more pronounced global warming manifestation than general climate change. Extreme heat events have adverse effects on both, ecosystems and human health, killing over 70,000 in 2003 alone. This study aims to validate that extreme heat events have been increasing in intensity, frequency, duration and affected-area over the past 40 years. The importance of properly defining heat events is stressed. As there is no exact definition, this study uses the adjusted NOAA National Weather Service definition, in terms of heat index, a reference to human comfort as defined by temperature and humidity. A heat wave is defined when maximum outside conditions of human comfort levels are present for consecutive days. Complex cities such as New York (NYC) are also expected to experience more intense heat events when considering the Urban Heat Island Effect. To observe the extent of recent heat events in NYC, heat event trends were produced using data from up to 59 NYCMetNet surface weather stations covering all five boroughs of the City. Map comparisons of heat events from recent years (2010-2012) demonstrate an increase in the effected metro areas with concentrated maximums in the northwest part of the city, attributed to the dense urban landscape and a converging wind zone. To investigate temporal trends of heat waves in NYC, four NOAA-NCDC weather stations in the NYC Metro Area were used, providing data from 1973-2012. The time series results indicate that heat wave maximum intensities are increasing in NYC as a function of time since 1973 at a rate of 1.2°C/decade. The temporal plots demonstrate an annual increase in maximum intensity, frequency, and average event duration that could be attributed to increasing heat island and global warming. Future studies will expand this

  10. Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

    Science.gov (United States)

    Ku, Jentung; Robinson, Franklin

    2016-01-01

    Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heaters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

  11. Methodology for estimation of potential for solar water heating in a target area

    International Nuclear Information System (INIS)

    Proper estimation of potential of any renewable energy technology is essential for planning and promotion of the technology. The methods reported in literature for estimation of potential of solar water heating in a target area are aggregate in nature. A methodology for potential estimation (technical, economic and market potential) of solar water heating in a target area is proposed in this paper. This methodology links the micro-level factors and macro-level market effects affecting the diffusion or adoption of solar water heating systems. Different sectors with end uses of low temperature hot water are considered for potential estimation. Potential is estimated at each end use point by simulation using TRNSYS taking micro-level factors. The methodology is illustrated for a synthetic area in India with an area of 2 sq. km and population of 10,000. The end use sectors considered are residential, hospitals, nursing homes and hotels. The estimated technical potential and market potential are 1700 m2 and 350 m2 of collector area, respectively. The annual energy savings for the technical potential in the area is estimated as 110 kW h/capita and 0.55 million-kW h/sq. km. area, with an annual average peak saving of 1 MW. The annual savings is 650-kW h per m2 of collector area and accounts for approximately 3% of the total electricity consumption of the target area. Some of the salient features of the model are the factors considered for potential estimation; estimation of electrical usage pattern for typical day, amount of electricity savings and savings during the peak load. The framework is general and enables accurate estimation of potential of solar water heating for a city, block. Energy planners and policy makers can use this framework for tracking and promotion of diffusion of solar water heating systems. (author)

  12. METHODS TO DETECT ATMOSPHERIC AND SURFACE HEAT ISLANDS IN URBAN AREAS

    OpenAIRE

    I. HERBEL; A. E. CROITORU; A. M. IMBROANE; D. PETREA

    2015-01-01

    Intensification of the urbanization process and its associated climatic effects is nowadays a major problem of large cities worldwide. One of these climatic effects is the urban heat island (UHI), that implies increased air and surface temperature values in the city when compared to the nearby rural areas. This phenomenon threatens the health of the population, especially during heat waves, affects the quality of the environment and the quality of life, and also generates significant costs to...

  13. Research Progress on the Problem of Fluid, Heat and Energy Distribution near the Earthquake Source Area

    Institute of Scientific and Technical Information of China (English)

    Yan Rui; Jiang Changsheng; Shao Zhigang; Zhou Longquan; Li Yingchun

    2011-01-01

    As the basic problems in seismology, fluid, heat and energy distribution near earthquake sources during earthquake generation have been the leading subjects of concern to seismologists. Currently, more and more research shows fluid around earthquake source areas, which plays an important role in the process of earthquake preparation and generation. However, there is considerable controversy over the source of fluid in the deep crust. As for the problem of heat around earthquake source areas, different models have been proposed to explain the stress heat flow paradox. Among them, the dynamic weakening model has been thought to be the key to solving the heat flow paradox issue. After large earthquakes, energy distribution is directly related to friction heat. It is of timely and important practical significance to immediately implement deep drilling in-site surveying to gain understanding of fluid, friction heat and energy distribution during earthquake generation. The latest international progress in fluid, heat and energy distribution research has been reviewed in this paper which will bring important inspiration for the understanding of earthquake preparation and occurrence.

  14. Remote Sensing Parameterization of Land Surface Heat Fluxes over Arid and Semi-arid Areas

    Institute of Scientific and Technical Information of China (English)

    马耀明; 王介民; 黄荣辉; 卫国安; MassimoMENENTI; 苏中波; 胡泽勇; 高峰; 文军

    2003-01-01

    Dealing with the regional land surfaces heat fluxes over inhomogeneous land surfaces in arid and semi-arid areas is an important but not an easy issue. In this study, one parameterization method based on satellite remote sensing and field observations is proposed and tested for deriving the regional land surface heat fluxes over inhomogeneous landscapes. As a case study, the method is applied to the Dunhuang experimental area and the HEIFE (Heihe River Field Experiment, 1988-1994) area. The Dunhuang area is selected as a basic experimental area for the Chinese National Key Programme for Developing Basic Sciences: Research on the Formation Mecbanism and Prediction Theory of Severe Climate Disaster in China (G1998040900, 1999-2003). The four scenes of Landsat TM data used in this study are 3 June 2000,22 August 2000, and 29 January 2001 for the Dunhuang area and 9 July 1991 for the HEIFE area. The regional distributions of land surface variables, vegetation variables, and heat fluxes over inhomogeneous landscapes in arid and semi-arid areas are obtained in this study.

  15. Effect of longwall face advance rate on spontaneous heating process in the gob area - CFD modelling

    Energy Technology Data Exchange (ETDEWEB)

    Boleslav Taraba; Zdenek Michalec [University of Ostrava, Ostrava (Czech Republic). Dept. of Chemistry

    2011-08-15

    A commercial CFD software programme, FLUENT, was used to study the oxidation process of coal in the mined-out longwall (gob) area. A three-dimensional, single-phase model with a continuously advancing longwall face has been developed. For the model, the gob longwall area was designed on the basis of the actual longwall panel operating in the Ostrava-Karvina Coal Mines (OKD, Czech Republic). The behaviour of the coal to oxygen was modelled using the results arising mainly from the former laboratory-scale experiments with Czech bituminous coals. Basically, the technique of pulse flow calorimetry and measurements at a continuous airflow reactor were applied during the laboratory investigations. In the contribution, the main focus was to understand the effect of the longwall face advancing speed on the oxidation heat production as well as evolution of the gases in the gob area. Simultaneously, the effect of coal crushing in the mined-out area on the spontaneous heating process was examined. Numerical simulations confirmed the existence of a 'favourable' zone for the onset and development of the spontaneous heating process in the gob area. The location and the maximal temperature reached in the 'favourable' zone were found to be significantly affected by the advancing rate of the coalface. The slower the advancing rate is, the higher the maximal temperature and smaller the depth of the 'favourable' zone in the gob area are. When the rate drops to a certain 'critical' value, spontaneous heating turns to flammable combustion of the coal. The value of the 'critical' advancing rate was confirmed to increase if the grain size of the coal left in the gob decreases. Numerical examinations of carbon monoxide concentrations then proved that small incidents of spontaneous heating could occur in the gob area that need not be detected in the airflow of the longwall tail gate. 46 refs., 8 figs., 2 tabs.

  16. Spatial variation of temperature and indicative of the urban heat island in Chennai Metropolitan Area, India

    Science.gov (United States)

    Jeganathan, Anushiya; Andimuthu, Ramachandran; Prasannavenkatesh, Ramachandran; Kumar, Divya Subash

    2016-01-01

    Heat island is the main product of urban climate, and one of the important problems of twenty-first century. Cities in tropical countries suffer extensively due to the urban heat island effect, and urban climate studies are necessary to improve the comfort level and city planning. Chennai is the tropical city; it is the fourth largest metropolis in India and one of the fastest growing economic and industrial growth centers in South Asia. The spatial distribution of heat intensity in Chennai Metropolitan Area was studied, and the influence of land use and green cover were analyzed in the present work. Mobile measurements were carried out throughout the study area using a grid network to represent various land use patterns of the city. The study revealed some heat and cool pockets within the city limit; the maximum intensities of temperature were noticed in the central core city and north Chennai, which are distinguished for their commercial centers and densely populated residential areas. In morning time, temperature differences between fringes and central parts of heat packets were in the range of 3-4.5 °C. Land use and green cover play a critical role in microclimate and influences it. Green cover has a significant negative correlation with observed microclimate variations. Thus, the study urges city administration, policy makers, and architects to take up effective mitigation and adaptation strategies in the city to make people more comfortable.

  17. Changes in the Seoul Metropolitan Area Urban Heat Environment with Residential Redevelopment

    Science.gov (United States)

    Hong, Je-Woo; Hong, Jinkyu

    2016-04-01

    Since the industrial revolution, the geographical extent of cities has increased around the world. In particular, following three decades of rapid regional economic growth, many Asian megacities have emerged and continue to expand. Short-term urban redevelopment is, therefore, inevitable. However, in this region the microclimatic impacts of urban redevelopment have not been extensively investigated using long-term in-situ observations. In this study, changes in surface sensible heat exchange, heat storage, and anthropogenic heat emissions due to urban residential redevelopment were quantified and analyzed based on a three-year micrometeorological record from the Seoul metropolitan area. The results show that following urban redevelopment of compact high-rise residential buildings, 1) the daily minimum air temperature near the ground surface increased by ˜0.6 K; 2) the ratio between surface sensible heat and net radiation increased by ˜ 9% (summer) to 31% (winter), anthropogenic heat emissions increased by 12 Wm-2 (spring) to 26 Wm-2 (summer), and daily maximum heat storage ranged by 35 Wm-2 (spring) to 55 Wm-2 (summer), and; 3) there was a transition of local circulation with changes in the surface properties of heat sources and roughness.

  18. Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

    Institute of Scientific and Technical Information of China (English)

    郭美茹; 朱启的; 孙志强; 周天; 周孑民

    2015-01-01

    To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles (ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area (UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15−363.15 K or 443.15−453.15 K, heptane is more suitable at 373.15−423.15 K, and R245ca is a good option at 483.15−503.15 K.

  19. Diurnal Variation of Soil Heat Flux at an Antarctic Local Area during Warmer Months

    Directory of Open Access Journals (Sweden)

    Marco Alves

    2016-01-01

    Full Text Available Soil heat flux (G is one term in the energy balance equation, and it can be particularly important in regions with arid, bare, or thinly vegetated soil surfaces. However, in remote areas such as the Antarctic, this measurement is not routinely performed. The analysis of observational data collected by the ETA Project at the Brazilian Antarctic Station from December 2013 to March 2014 showed that, for the total daily energy flux, the surface soil flux heats the deeper soil layers during December and January and G acts as a heat source to the outer soil layers during February and March. With regard to daytime energy flux, G acts as a source of heat to the deeper layers. During the night-time, the soil is a heat source to the shallower soil layers and represents at least 29% of the net night-time radiation. A relatively simple method—the objective hysteresis method (OHM—was successfully applied to determine the surface soil heat flux using net radiation observations. A priori, the OHM coefficients obtained in this study may only be used for short-time parameterizations and for filling data gaps at this specific site.

  20. Testing of a Neon Loop Heat Pipe for Large Area Cryocooling

    Science.gov (United States)

    Ku, Jentung; Robinson, Franklin Lee

    2014-01-01

    Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.

  1. Influence of new town development on the urban heat island - The case of the Bundang area

    Institute of Scientific and Technical Information of China (English)

    SONG Young-bae

    2005-01-01

    Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 1985 to 1999 rapidly developed which showed a difference of mean temperature above + 2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings.The mean temperature of the residential and commercial areas in the study was found to be + 4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island.

  2. Costs of urban area retrofit to district heating and cooling systems: north-central cities

    Energy Technology Data Exchange (ETDEWEB)

    Santini, D J; Davis, A A; Marder, S M

    1978-03-01

    This study considers the major urbanized areas of six U.S. cities (Washington, D.C.; St. Louis; Cleveland; Milwaukee; Detroit; Chicago) to arrive at reasonably accurate estimates of costs required to retrofit them with district heating and cooling systems. Only costs associated with heating and hot water are addressed here. Demand estimates and energy-supply analyses are made, and component capital costs are estimated to arrive at annualized system costs. Finally, a comparison of alternative energy-delivery options is made, and estimates of scarce-fuel savings are derived. 39 refs., 12 figs., 14 tables.

  3. Mitigation of urban heat stress – a modelling case study for the area of Stuttgart

    Directory of Open Access Journals (Sweden)

    Fallmann, Joachim

    2014-04-01

    Full Text Available In 2050 the fraction of urban global population will increase to over 69%, which means that around 6.3 billion people are expected to live in urban areas (UN 2011. Cities are the predominant habitation places for humans to live and are vulnerable to extreme weather events aggravating phenomena like heat stress. Finding mitigation strategies to sustain future development is of great importance, given expected influences on human health. In this study, the mesoscale numerical model WRF is used on a regional scale for the urban area of Stuttgart, to simulate the effect of urban planning strategies on dynamical processes affecting urban climate. After comparing two urban parameterisation schemes, a sensitivity study for different scenarios is performed; it shows that a change of the reflective properties of surfaces has the highest impact on near-surface temperatures compared to an increase of urban green areas or a decrease of building density. The Urban Heat Island (UHI describes the temperature difference between urban and rural temperatures; it characterises regional urban climate and is responsible for urban-rural circulation patterns. Applying urban planning measures may decrease the intensity of the UHI in the study area by up to 2 °C by using heat-reflective roof paints or by 1 °C through replacing impervious surfaces by natural vegetation in the urban vicinity – compared to a value of 2.5 °C for the base case. Because of its topographical location in a valley and the overall high temperatures in this region, the area of Stuttgart suffers from heat stress to a comparatively large extent.

  4. METHODS TO DETECT ATMOSPHERIC AND SURFACE HEAT ISLANDS IN URBAN AREAS

    Directory of Open Access Journals (Sweden)

    I. HERBEL

    2015-10-01

    Full Text Available Intensification of the urbanization process and its associated climatic effects is nowadays a major problem of large cities worldwide. One of these climatic effects is the urban heat island (UHI, that implies increased air and surface temperature values in the city when compared to the nearby rural areas. This phenomenon threatens the health of the population, especially during heat waves, affects the quality of the environment and the quality of life, and also generates significant costs to ensure the inhabitants' thermal comfort. In this study we present a review of the UHI concept and three of the main methods used to detect the atmospheric and surface urban heat islands. Satellite image data analysis seems an easier and time-saving solution, but due to its limitations, we consider that a combination of both surfaces and lower atmospheric layer temperature data analysis is the best choice in order to get accurate results of the intensity and spatial extension of the UHI.

  5. Autonomous distributed temperature sensing for long-term heated applications in remote areas

    Directory of Open Access Journals (Sweden)

    A.-M. Kurth

    2013-02-01

    Full Text Available Distributed temperature sensing (DTS is a fiber-optical method enabling simultaneous temperature measurements over long distances. Electrical resistance heating of the metallic components of the fiber-optic cable provides information on the thermal characteristics of the cable's environment, providing valuable insight into processes occurring in the surrounding medium, such as groundwater–surface water interactions, dam stability or soil moisture. Until now, heated applications required direct handling of the DTS instrument by a researcher, rendering long-term investigations in remote areas impractical due to the often difficult and time-consuming access to the field site. Remote control and automation of the DTS instrument and heating processes, however, resolve the issue with difficult access. The data can also be remotely accessed and stored on a central database. The power supply can be grid independent, although significant infrastructure investment is required here due to high power consumption during heated applications. Solar energy must be sufficient even in worst case scenarios, e.g. during long periods of intense cloud cover, to prevent system failure due to energy shortage. In combination with storage batteries and a low heating frequency, e.g. once per day or once per week (depending on the season and the solar radiation on site, issues of high power consumption may be resolved. Safety regulations dictate adequate shielding and ground-fault protection, to safeguard animals and humans from electricity and laser sources. In this paper the autonomous DTS system is presented to allow research with heated applications of DTS in remote areas for long-term investigations of temperature distributions in the environment.

  6. Autonomous distributed temperature sensing for long-term heated applications in remote areas

    Directory of Open Access Journals (Sweden)

    A.-M. Kurth

    2012-10-01

    Full Text Available Distributed Temperature Sensing (DTS is a fiber-optical method enabling simultaneous temperature measurements over long distances. Electrical resistance heating of the metallic components of the fiber-optic cable provides information on the thermal characteristics of the cable's environment, providing valuable insight into processes occurring in the surrounding medium, such as groundwater-surface water interactions, dam stability or soil moisture. Until now, heated applications required direct handling of the DTS instrument by a researcher, rendering long-term investigations in remote areas impractical due to the often difficult and time-consuming access to the field site. Remote-control and automation of the DTS instrument and heating processes, however, resolve the issue with difficult access. The data can also be remotely accessed and stored on a central database. The power supply can be grid-independent, although significant infrastructure investment is required here due to high power consumption during heated applications. Solar energy must be sufficient even in worst case scenarios, e.g. during long periods of intense cloud cover, to prevent system failure due to energy shortage. In combination with storage batteries and a low heating frequency, e.g. once per day or once per week (depending on the season and the solar radiation on site, issues of high power consumption may be resolved. Safety regulations dictate adequate shielding and ground-fault protection, to safeguard animals and humans from electricity and laser sources. In this paper the autonomous DTS system is presented to allow research with heated applications of DTS in remote areas for long-term investigations of temperature distributions in the environment.

  7. A heat island model for large urban areas and its application to Milan

    International Nuclear Information System (INIS)

    The study of the urban heat island has been carried out through two enhanced versions of the UCLM (urban canopy layer model) model, Landsat/Thematic Mapper data sets and meteorological data collected over a square area 30 km of side including Milan and its hinterland (Italy). The urban climate can be describe in different summer and winter radiative settings. The input data are divided into two classes: 1, parameters related to urban and rural properties; 2, meteorological data related to the general synoptic conditions. The bulk system of the model is made up of four independent equations expressed in terms of four unknowns, i.e., the temperature values at ground level, canopy level and reference level (100 m) and relative humidity within the urban structure. The study area is divided by a regular square mesh of variable dimension; both the input and output data are average cell values. UCLM30 and UCLM60 calculate the temperature excess as well as the turbulent heat exchanges and the heat storage in the urban canopy as a function of the radiative and dynamic forcing. As can be observed in reality, the model shows that in summer the highest urban heating occurs in early morning and after sunset and that, in extreme conditions, the temperature can be up to 80 C warmer in town than in the nearby rural lands

  8. DHC in Helsinki - The Ultimate Heating and Cooling Solution for a Large Urban Area

    Energy Technology Data Exchange (ETDEWEB)

    Wirgentius, Niko; Riipinen, Marko

    2010-09-15

    Since the 1950s there has been successful district energy business in Helsinki. It has been the main factor for superior energy efficiency and low CO2 emissions both in heating and cooling as well as providing clean air for the metropolitan area. The system has been grown by commercial basis based on customers' own willingness to select district energy solution. It also provided a profitable energy business to local energy company, Helsinki Energy. Helsinki DHC system is a good example of ultimate urban energy solution that provides benefits for the customer, energy company, metropolitan area and for the whole society as well.

  9. The effect of the overall heat transfer coefficient variation on the optimal distribution of the heat transfer surface conductance or area in a Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Costea, M. [Polytechnic University of Bucharest (Romania). Dept. of Applied Thermodynamics; Feidt, M. [University H. Poincare of Nancy (France)

    1998-12-31

    This study aims to assess for a Stirling engine the influence of the overall heat transfer coefficient variation on the optimum state and on the optimum distribution of the heat transfer surface conductance or area among the machine heat exchangers. The analysis is based on a Stirling machine optimization method, previously elaborated, which is now applied to a cycle with total heat regeneration. The method was conceived for an irreversible cycle with heat transfer across temperature differences at the source and the sink, and heat losses between the hot-end and the cold-end of the engine. Source and sink of finite thermal capacity as well as thermostats are considered. The new approach considers a linear variation of the overall heat transfer coefficient of the machine heat exchangers with respect to the local temperature difference. A comparison of the optimum state and the optimum distribution of the heat transfer surface conductance or area among the heater and the cooler is made for several cases. (author)

  10. Low-energy district heating in energy-efficient building areas

    International Nuclear Information System (INIS)

    This paper presents an innovative low-energy district heating (DH) concept based on low-temperature operation. The decreased heating demand from low-energy buildings affects the cost-effectiveness of traditionally-designed DH systems, so we carried out a case study of the annual energy performance of a low-energy network for low-energy houses in Denmark. We took into account the effect of human behaviour on energy demand, the effect of the number of buildings connected to the network, a socio-economic comparison with ground source heat pumps, and opportunities for the optimization of the network design, and operational temperature and pressure. In the north-European climate, we found that human behaviour can lead to 50% higher heating demand and 60% higher heating power than those anticipated in the reference values in the standard calculations for energy demand patterns in energy-efficient buildings. This considerable impact of human behaviour should clearly be included in energy simulations. We also showed that low-energy DH systems are robust systems that ensure security of supply for each customer in a cost-effective and environmentally friendly way in areas with linear heat density down to 0.20 MWh/(m year), and that the levelized cost of energy in low-energy DH supply is competitive with a scenario based on ground source heat pumps. The investment costs represent up to three quarters of the overall expenditure, over a time horizon of 30 years; so, the implementation of an energy system that fully relies on renewable energy needs substantial capital investment, but in the long term this is sustainable from the environmental and socio-economic points of view. Having demonstrated the value of the low-energy DH concept, we evaluated various possible designs with the aim of finding the optimal solution with regard to economic and energy efficiency issues. Here we showed the advantage of low supply and return temperatures, their effect on energy efficiency and that

  11. Geothermal concept for energy efficient improvement of space heating and cooling in highly urbanized area

    Directory of Open Access Journals (Sweden)

    Vranjes Ana

    2015-01-01

    Full Text Available New Belgrade is a highly urbanized commercial and residential district of Belgrade lying on the alluvial plane of the Sava and the Danube rivers. The groundwater of the area is a geothermal resource that is usable through geothermal heat pumps (GHP. The research has shown that the “heat island effect” affects part of the alluvial groundwater with the average groundwater temperature of about 15.5°C, i.e. 2°C higher than the one in less urbanized surroundings. Based on the measured groundwater temperatures as well as the appraisal of the sustainable aquifer yield, the available thermal power of the resource is estimated to about 29MWt. The increasing urbanization trend of the New Belgrade district implies the growing energy demands that may partly be met by the available groundwater thermal power. Taking into consideration the average apartment consumption of 80 Wm-2, it is possible to heat about 360,000 m2 and with the consumption efficiency of 50 Wm-2, it would be possible to heat over 570,000 m2. Environmental and financial aspects were considered through the substitution of conventional fuels and the reduction of greenhouse gas emission as well as through the optimization of the resource use.

  12. Investigation and assessment of interfacial area/interfacial heat and mass transfer correlations in SPACE code

    International Nuclear Information System (INIS)

    SPACE, which is a safety analysis code for nuclear power plants, has been developed to analyze the multidimensional, two-component and three-field flow. This code can be applied to safety analysis for approval which is thermal-hydraulic analysis to support the nuclear power station design, establishment of accident ease strategy, development of operating guide line, experiment plan and analysis. To do so, SPACE code has the interfacial area and interfacial heat and mass transfer to predict the physical phenomenon occurring at the interface between two different phases. In this report, the physical correlation models are explained and their performance is assessed against several SET

  13. Analysis on the Changes of Temperature and Heat Resources in Rural Area of Chaoyang in Western Liaoning

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The aim was to study the change characteristics of temperature and heat resources in rural area of Chaoyang in western Liaoning. [Method] Based on the data from rural meteorological station in Chaoyang in western Liaoning from 1966 to 2010, the change characteristics of temperature and heat resources in rural area in Chaoyang were analyzed by means of serial correlation and climate tendency method, so as to master its climate situation. [Result] The annual average value of daily average temperat...

  14. Monitoring the effect of urban green areas on the heat island in Athens.

    Science.gov (United States)

    Zoulia, I; Santamouris, M; Dimoudi, A

    2009-09-01

    The role of urban green areas in the microclimatic conditions of cities, during summer, is investigated in this paper through monitoring campaigns carried out at the National garden, at the city centre of Athens. Two types of investigations were carried out: i) a microscopic one that investigated the thermal conditions inside the Garden and the immediate surrounding urban area and ii) a macroscopic one that compared the temperature profile of the Garden with that of the greater city centre area. It was concluded that in microscopic level, the temperature profile inside the National Garden and the immediate surrounding urban area did not showed a clear evidence of the influence of the Garden and it was dependent on the characteristics of each location. In a macroscopic scale, the Garden was found cooler than the other monitored urban locations and temperature differences were mainly greater during the night, especially in streets with high building height to street width (H/W) ratio and low traffic, while in streets with high anthropogenic heat during the day, the biggest temperature differences were recorded during the day.

  15. The thermal performance of seawater-source heat pump systems in areas of severe cold during winter

    International Nuclear Information System (INIS)

    Highlights: • Thermal performance of SWHP systems with HCHE and BWIS are compared with ASHP. • Exergy efficiencies and destruction rates of SWHP and ASHP system are performed. • HSPF is used to express the performance of heat pump systems. • Economic analyses of the heat pump systems are performed and compared. - Abstract: The research concerning ocean energy exploitation in North China is undoubtedly of significant importance to the development of the national ocean energy. The use of seawater heat pump (SWHP) systems is a better choice than air-source heat pump (ASHP) systems. The latter systems have a lower efficiency because of the formation of frost on the surface of its airside heat exchanger when the ambient air temperature is low. This paper reports research investigating the system efficiency of SWHP systems in areas of severe cold during winter. Experiments are conducted to compare the thermal performance of the beach well infiltration intake systems (BWIS) and the helical coil heat exchanger (HCHE) for SWHP systems in the Bohai Sea, Tianjin, North China. Heat transfer rate, COP (coefficient of performance) values, exergy efficiencies and exergy destruction rates of the SWHP systems with BWIS and HCHE are presented and compared with the ASHP systems. The study results indicate that the BWIS for SWHP systems has the highest thermal performance during the whole heating season in areas of severe cold during winter. That performance is observed because icing on the outer surfaces of the tubes of the HCHE and frost formation on the surface of the heat exchanger of the ASHP have great effects on the heat transfer performance. The Heating seasonal performance factor (HSPF) is used to express the performance of heat pump systems over the entire heating season. Economic analyses of the BWIS and HCHE are performed according to local economics to compare the application of the HCHE and BWIS, and the results indicate that the HCHE has a better economic value

  16. The Urban Heat Island Behavior of a Large Northern Latitude Metropolitan Area

    Science.gov (United States)

    Twine, T. E.; Snyder, P. K.; Hertel, W.; Mykleby, P.

    2012-12-01

    Urban heat islands (UHIs) occur when urban and suburban areas experience elevated temperatures relative to their rural surroundings because of differences in vegetation cover, buildings and other development, and infrastructure. Most cities in the United States are warming at twice the rate of the outlying rural areas and the planet as a whole. Temperatures in the urban center can be 2-5°C warmer during the daytime and as much as 10°C at night. Urban warming is responsible for excessive energy consumption, heat-related health effects, an increase in urban pollution, degradation of urban ecosystems, changes in the local meteorology, and an increase in thermal pollution into urban water bodies. One mitigation strategy involves manipulating the surface energy budget to either reduce the amount of solar radiation absorbed at the surface or offset absorbed energy through latent cooling. Options include using building materials with different properties of reflectivity and emissivity, increasing the reflectivity of parking lots, covering roofs with vegetation, and increasing the amount of vegetation overall through tree planting or increasing green space. The goal of the Islands in the Sun project is to understand the formation and behavior of urban heat islands and to mitigate their effects through sensible city engineering and design practices. As part of this project, we have been characterizing the UHI of the Twin Cities Metropolitan Area (TCMA), a 16,000 square kilometer urban and suburban region located in east central Minnesota that includes the two cities of Minneapolis and Saint Paul, and evaluating mitigation strategies for reducing urban warming. Annually, the TCMA has a modest 2-3°C UHI that is especially apparent in winter when the urban core can be up to 5-6°C warmer than the surrounding countryside. We present an analysis of regional temperature variations from a dense network of sensors located throughout the TCMA. We focus on the diurnal and seasonal

  17. Ground-Coupled Heating-Cooling Systems in Urban Areas: How Sustainable Are They?

    Science.gov (United States)

    Younger, Paul L.

    2008-01-01

    Ground-coupled heating-cooling systems (GCHCSs) exchange heat between the built environment and the subsurface using pipework buried in trenches or boreholes. If heat pumps in GCHCSs are powered by "green electricity," they offer genuine carbon-free heating-cooling; for this reason, there has been a surge in the technology in recent years.…

  18. Regulatory framework and examples of ground-source heating/cooling technology in the Winnipeg area

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, R. [Manitoba Conservation, Winnipeg, MB (Canada)

    2003-07-01

    Winnipeg, Manitoba lies over a highly transmissive Carbonate Aquifer of Ordovician age, which provides a suitable environment for groundwater supply and return wells. Many licensed ground-source heating cooling (GSHC) systems have been installed in and around the Winnipeg urban area over the last several decades. A water rights licence, issued by the Provincial Department of Conservation, is required for all groundwater supply and return wells. This licence comes with certain rights and responsibilities. This paper describes the regulatory framework which governs the licensing process. The author emphasized that the future use and success of the technology depends, in large part, on the development of a critical mass of experienced contractors, hydrogeologists and consulting engineers. 2 refs.

  19. Is there any relation between helium isotope composition of underground fluids and heat flow in continental areas?

    Institute of Scientific and Technical Information of China (English)

    汪洋

    2001-01-01

    The regression formula between 3He/4He ratio of underground fluids and terrestrial heat flow in continental areas is tested by data sets from the former Soviet Union and the mainland of China. The results show that there is no close relation between the two values. The heat-He relation might estimate the regional heat flow value with ±25% accuracy at best. We propose that the ratio of crust/mantle component of continental heat flow (qc/qm) be inversely related to the 3He/4He ratio of underground fluids. Based on data sets of 3He/4He ratio and qc/qm in the Eurasia and Canadian Shield, we obtain the regression relation between qc/qm and 3He/4He: qc/qm = 0.815-0.300*loge(3He/4He), in which the unit of 3He/4He is Ra (atmospheric 3He/4He ratio). The crust and mantle heat flow components can be taken from surface heat flow and qc/qm ratio. Based on this formula and heat flow data in major basins of China, the crustal, mantle heat flow values and the average crustal heat production rates were estimated. The es

  20. Selection of heating schemes in Hunan area%湖南地区供暖方式选择

    Institute of Scientific and Technical Information of China (English)

    欧阳焱; 刘光大

    2013-01-01

    简要介绍了湖南地区的气候特点和供暖的历史和现状,结合工程实例,分析了集中燃气锅炉供暖、分户壁挂炉供暖、分体空调供暖和集中地源热泵供暖几种供暖方案的效果、系统投资、能耗与运行成本,就湖南地区供暖方式的选择给出了建议.%Briefly presents the characteristics of climate,the history and current status of heating schemes in Hunan.With a project example,analyses the heating effect,investment of the system,energy consumption and running costs of the heating methods including gas boiler central heating,gas boiler household heating,split air conditioner heating and ground source heat pump heating.Puts forward some suggestions for selection of heating schemes in Hunan area.

  1. Comparison of Turbulent Sensible Heat Flux Determined by Large-Aperture Scintillometer and Eddy Covariance over Urban and Suburban Areas

    Science.gov (United States)

    Zhang, He; Zhang, Hongsheng

    2015-01-01

    Field observations of the atmospheric boundary layer were made over urban and suburban areas in the Yangtze River Delta, China. Sensible heat fluxes were obtained by eddy-covariance (EC) systems and large-aperture scintillometers (LASs). The results indicated that (1) the sensible heat flux obtained by LAS was less noisy and slightly larger than that obtained by EC over both urban and suburban surfaces; (2) the values of were higher when the correlation coefficient of vertical wind speed and temperature () was smaller. Lower values of were due to low-frequency trends. The urban values of were smaller than suburban values at low values; (3) the sensible heat flux determined by LAS was improved by use of the Monin-Obukhov similarity theory of the temperature structure parameter over urban and suburban areas, and the improvement is more significant over urban surface areas.

  2. Sensitivity of Large-Aperture Scintillometer Measurements of Area-Average Heat Fluxes to Uncertainties in Topographic Heights

    CERN Document Server

    Gruber, Matthew A; Hartogensis, Oscar K

    2013-01-01

    Scintillometers measure $C_n^2$ over large areas of turbulence in the atmospheric surface layer. Turbulent fluxes of heat and momentum are inferred through coupled sets of equations derived from the Monin-Obukhov similarity hypothesis. One-dimensional sensitivity functions have been produced which relate the sensitivity of heat fluxes to uncertainties in single values of beam height over homogeneous and flat terrain. Real field sites include variable topography and heterogeneous surface properties such as roughness length. We develop here the first analysis of the sensitivity of scintillometer derived sensible heat fluxes to uncertainties in spacially distributed topographic measurements. For large-aperture scintillometers and independent $u_\\star$ measurements, sensitivity is shown to be concentrated in areas near the center of the beam and where the underlying topography is closest to the beam height. Uncertainty may be greatly reduced by focusing precise topographic measurements in these areas. The new two...

  3. Regional heat flux over the NOPEX area estimated from the evolution of the mixed-layer

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Batchvarova, E.

    1999-01-01

    of forest, agricultural fields, mires and lakes within the boreal zone, was determined for 3 days of the campaign in 1994. It was found to be lower than the heat flux over forest and higher than the heat Aux over agricultural fields. The regional heat flux estimated by the mixed-layer evolution method...... was compared to a land-use-weighted average heat flux. The two independent estimates of the regional heat Bur were found to be in general agreement. (C) 1999 Elsevier Science B.V. All rights reserved....

  4. Furnace and Heat Recovery Area Design and Analysis for Conceptual Design of Oxygen-Based PC Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Seltzer

    2005-01-01

    The objective of the furnace and heat recovery area design and analysis task of the Conceptual Design of Oxygen-Based PC Boiler study is to optimize the location and design of the furnace, burners, over-fire gas ports, and internal radiant surfaces. The furnace and heat recovery area were designed and analyzed using the FW-FIRE and HEATEX computer programs. The furnace is designed with opposed wall-firing burners and over-fire air ports. Water is circulated in the furnace by natural circulation to the waterwalls and divisional wall panels. Compared to the air-fired furnace, the oxygen-fired furnace requires only 65% of the surface area and 45% of the volume. Two oxygen-fired designs were simulated: (1) without over-fire air and (2) with 20% over-fire air. The maximum wall heat flux in the oxygen-fired furnace is more than double that of the air-fired furnace due to the higher flame temperature and higher H{sub 2}O and CO{sub 2} concentrations. The coal burnout for the oxygen-fired case is 100% due to a 500 F higher furnace temperature and higher concentration of O{sub 2}. Because of the higher furnace wall temperature of the oxygen-fired case compared to the air-fired case, furnace water wall material was upgraded from carbon steel to T91. The total heat transfer surface required in the oxygen-fired heat recovery area (HRA) is 25% less than the air-fired HRA due to more heat being absorbed in the oxygen-fired furnace and the greater molecular weight of the oxygen-fired flue gas. The HRA tube materials and wall thickness are practically the same for the air-fired and oxygen-fired design since the flue gas and water/steam temperature profiles encountered by the heat transfer banks are very similar.

  5. Influences of land cover types, meteorological conditions, anthropogenic heat and urban area on surface urban heat island in the Yangtze River Delta Urban Agglomeration.

    Science.gov (United States)

    Du, Hongyu; Wang, Duoduo; Wang, Yuanyuan; Zhao, Xiaolei; Qin, Fei; Jiang, Hong; Cai, Yongli

    2016-11-15

    Urban heat islands (UHIs) reflect the localized impact of human activities on thermal fields. In this study, we assessed the surface UHI and its relationship with types of land, meteorological conditions, anthropogenic heat sources and urban areas in the Yangtze River Delta Urban Agglomeration (YRDUA) with the aid of remote sensing data, statistical data and meteorological data. The results showed that the UHI intensity in YRDUA was the strongest (0.84°C) in summer, followed by 0.81°C in autumn, 0.78°C in spring and 0.53°C in winter. The daytime UHI intensity is 0.98°C, which is higher than the nighttime UHI intensity of 0.50°C. Then, the relationship between the UHI intensity and several factors such as meteorological conditions, anthropogenic heat sources and the urban area were analysed. The results indicated that there was an insignificant correlation between population density and the UHI intensity. Energy consumption, average temperature and urban area had a significant positive correlation with UHI intensity. However, the average wind speed and average precipitation were significantly negatively correlated with UHI intensity. This study provides insight into the regional climate characteristics and a scientific basis for city layout. PMID:27424113

  6. Heat flow studies in the Steamboat Mountain-Lemei Rock area, Skamania County, Washington. Information circular 62

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.E.; Blackwell, D.D.; Hammond, P.E.; Huntting, M.T.

    1978-01-01

    In order to investigate the possible occurrence of geothermal energy in areas of Quaternary basaltic volcanism, the Washington State Department of Natural Resources drilled several 152 m deep heat-flow holes in the Steamboat Mountain-Lemei Rock area of Skamania County, Washington. The study area is located in the southern part of Washington's Cascade Mountains between 45/sup 0/54' and 46/sup 0/07' N. and 121/sup 0/40' and 121/sup 0/53'W. This area was selected for study because geologic mapping had identified a north-trending chain of late Quaternary basaltic volcanoes that had extruded a sequence of lava flows up to 600 m thick and because the chain of volcanoes is areally coincident with a well-defined gravity low with a minimum value of about -110 mgals. Gradients of 52.7 and 53.4/sup 0/C/km and heat flows of 1.8 and 1.6 ..mu..cal/cm/sup 2/sec, respectively, were measured in two drill holes near the east flank of the chain of volcanoes. Gradients of 44.5 and 58/sup 0/C/km and heat flows of 1.3 and 1.6 ..mu..cal/cm/sup 2/ sec, respectively, were measured in two holes near the axis of the chain, and one gradient of 49.8/sup 0/C/km and heat flow of 1.5 ..mu..cal/cm/sup 2/ sec were measured in a drill hole near the west flank of the chain. All gradients and heat flows are terrain corrected. These heat-flow values are typical regional heat-flow values for the Cascade Mountains. The data show that there is no large-sized heat source body within the general area of the heat-flow study. However, there is only one location in Washington, also in the Cascade Mountains, where higher gradients have been measured.

  7. Tectonic heat flow modelling for basin maturation - Implications for frontier areas in the mediterranean

    NARCIS (Netherlands)

    Wees, J.D. van; Bonte, D.; Nelskamp, S.

    2009-01-01

    Basement heat flow is one of the most influential parameters on basin maturity. Although rapid progress has been made in the development of tectonic models capable of modelling the thermal consequences of basin formation, these models are hardly used in basin modelling. To better predict heat flows

  8. Low-energy district heating in energy-efficient building areas

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Christensen, Jørgen Erik

    2011-01-01

    This paper presents an innovative low-energy district heating (DH) concept based on low-temperature operation. The decreased heating demand from low-energy buildings affects the cost-effectiveness of traditionally-designed DH systems, so we carried out a case study of the annual energy performance...... of a low-energy network for low-energy houses in Denmark. We took into account the effect of human behaviour on energy demand, the effect of the number of buildings connected to the network, a socio-economic comparison with ground source heat pumps, and opportunities for the optimization of the network...... design, and operational temperature and pressure. In the north-European climate, we found that human behaviour can lead to 50% higher heating demand and 60% higher heating power than those anticipated in the reference values in the standard calculations for energy demand patterns in energy-efficient...

  9. Sensitivity of Displaced-Beam Scintillometer Measurements of Area-Average Heat Fluxes to Uncertainties in Topographic Heights

    CERN Document Server

    Gruber, Matthew; Hartogensis, Oscar

    2014-01-01

    Displaced-beam scintillometer measurements of the turbulence inner-scale length $l_o$ and refractive index structure function $C_n^2$ resolve area-average turbulent fluxes of heat and momentum through the Monin-Obukhov similarity equations. Sensitivity studies have been produced for the use of displaced-beam scintillometers over flat terrain. Many real field sites feature variable topography. We develop here an analysis of the sensitivity of displaced-beam scintillometer derived sensible heat fluxes to uncertainties in spacially distributed topographic measurements. Sensitivity is shown to be concentrated in areas near the center of the beam and where the underlying topography is closest to the beam height. Uncertainty may be decreased by taking precise topographic measurements in these areas.

  10. Annual emissions and air-quality impacts of an urban area district-heating system: Boston case study

    Energy Technology Data Exchange (ETDEWEB)

    Bernow, S.S.; McAnulty, D.R.; Buchsbaum, S.; Levine, E.

    1980-02-01

    A district-heating system, based on thermal energy from power plants retrofitted to operate in the cogeneration mode, is expected to improve local air quality. This possibility has been examined by comparing the emissions of five major atmospheric pollutants, i.e., particulates, sulfur oxides, carbon monoxide, hydrocarbons, and nitrogen oxides, from the existing heating and electric system in the City of Boston with those from a proposed district heating system. Detailed, spatial distribution of existing heating load and fuel mix is developed to specify emissions associated with existing heating systems. Actual electric-power-plant parameters and generation for the base year are specified. Additional plant fuel consumption and emissions resulting from cogeneration operation have been estimated. Six alternative fuel-emissions-control scenarios are considered. The average annual ground-level concentrations of sulfur oxides are calculated using a modified form of the EPA's Climatological Dispersion Model. This report describes the methodology, the results and their implications, and the areas for extended investigation. The initial results confirm expectations. Average sulfur oxides concentrations at various points within and near the city drop by up to 85% in the existing fuels scenarios and by 95% in scenarios in which different fuels and more-stringent emissions controls at the plants are used. These reductions are relative to concentrations caused by fuel combustion for heating and large commercial and industrial process uses within the city and Boston Edison Co. electric generation.

  11. ENERGY AND ENVIRONMENTAL ANALYSIS OF AN OPEN-LOOP GROUND-WATER HEAT PUMP SYSTEM IN AN URBAN AREA

    Directory of Open Access Journals (Sweden)

    Giorgia Baccino

    2010-01-01

    Full Text Available In this paper a multidisciplinary methodology for analyzing the opportunities for exploitation of open-loop groundwater heat pump is proposed. The approach starts from a model for calculation of a time profile of thermal requirements (heat and domestic hot water. This curve is then coupled with a model of the control system in order to determine the heat pump operation, which includes its energy performances (primary energy consumption as well as profiles of water discharge to the aquifer in terms of mass flow rate and temperature. Then the thermo-fluid dynamics of the aquifer is performed in order to determine the system impact on the environment as on possible other systems. The application to a case study in the Piedmont region, in Italy, is proposed. Energy analysis of the system shows that ground-water heat pumps constitute an interesting option in areas with small housing density, where there is not district heating. In comparison with typical heating/cooling systems, environmental benefits are related with reduction in global emissions. These benefits may be significantly enhanced using renewables as the primary energy source to produce electricity. The analysis also shows that possible issues related with the extension of the subsurface thermal plume may arise in the case of massive utilization of this technology.

  12. Energy impacts of heat island reduction strategies in the Greater Toronto Area, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Konopacki, Steven; Akbari, Hashem

    2001-11-30

    In 2000, the Toronto Atmospheric Fund (TAF) embarked on an initiative to quantify the potential benefits of Heat Island Reduction (HIR) strategies (shade trees, reflective roofs and pavements) in reducing cooling energy use in buildings, lowering the ambient air temperature and improve air quality. This report summarizes the efforts of Lawrence Berkeley National Laboratory (LBNL) to assess the impacts of HIR measures on building cooling- and heating-energy use. We discuss our efforts to calculate annual energy savings and peak-power avoidance of HIR strategies in the building sector of the Greater Toronto Area. The analysis is focused on three major building types that offer most saving potentials: residence, office and retail store. Using an hourly building energy simulation model, we quantify the energy saving potentials of (1) using cool roofs on individual buildings [direct effect], (2) planting deciduous shade trees near south and west walls of building [direct effect], (3) planting coniferous wind-shielding vegetation near building [direct effect], (4) ambient cooling by a large-scale program of urban reforestation with reflective building roofs and pavements [indirect effect], (5) and the combined direct and indirect effects. Results show potential annual energy savings of over $11M (with uniform residential and commercial electricity and gas prices of $0.084/kWh and $5.54/GJ) could be realized by ratepayers from the combined direct and indirect effects of HIR strategies. Of that total, about 88 percent was from the direct impact roughly divided equally among reflective roofs, shade trees and wind-shielding, and the remainder (12 percent) from the indirect impact of the cooler ambient air temperature. The residential sector accounts for over half (59 percent) of the total, offices 13 percent and retail stores 28 percent. Savings from cool roofs were about 20 percent, shade trees 30 percent, wind shielding of tree 37 percent, and indirect effect 12 percent

  13. Energy impacts of heat island reduction strategies in the Greater Toronto Area, Canada; FINAL

    International Nuclear Information System (INIS)

    In 2000, the Toronto Atmospheric Fund (TAF) embarked on an initiative to quantify the potential benefits of Heat Island Reduction (HIR) strategies (shade trees, reflective roofs and pavements) in reducing cooling energy use in buildings, lowering the ambient air temperature and improve air quality. This report summarizes the efforts of Lawrence Berkeley National Laboratory (LBNL) to assess the impacts of HIR measures on building cooling- and heating-energy use. We discuss our efforts to calculate annual energy savings and peak-power avoidance of HIR strategies in the building sector of the Greater Toronto Area. The analysis is focused on three major building types that offer most saving potentials: residence, office and retail store. Using an hourly building energy simulation model, we quantify the energy saving potentials of (1) using cool roofs on individual buildings[direct effect], (2) planting deciduous shade trees near south and west walls of building[direct effect], (3) planting coniferous wind-shielding vegetation near building[direct effect], (4) ambient cooling by a large-scale program of urban reforestation with reflective building roofs and pavements[indirect effect], (5) and the combined direct and indirect effects. Results show potential annual energy savings of over$11M (with uniform residential and commercial electricity and gas prices of$0.084/kWh and$5.54/GJ) could be realized by ratepayers from the combined direct and indirect effects of HIR strategies. Of that total, about 88 percent was from the direct impact roughly divided equally among reflective roofs, shade trees and wind-shielding, and the remainder (12 percent) from the indirect impact of the cooler ambient air temperature. The residential sector accounts for over half (59 percent) of the total, offices 13 percent and retail stores 28 percent. Savings from cool roofs were about 20 percent, shade trees 30 percent, wind shielding of tree 37 percent, and indirect effect 12 percent. These

  14. Heat flow and its coalbed gas effects in the central-south area of the Huaibei coalfield, eastern China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on an analysis of the present geo-temperature field and the thermal conductivity (K) of 62 samples from the central-south area of the Huaibei coalfield in eastern China, we calculated the heat flow and plotted its distribution map. The results show that the average heat flow in the research area is about 60 mW/m2. It is different from other major energy basins in the North China Plate, but has close relationship with the regional geology and the deep geological setting. The heat flow is comparatively higher in the southeastern, central, and northwestern areas than in the northeastern and southwestern areas. The geo-temperature distribution map of the bottom interface of the Permian coal measure was drawn by calculating its embedding depth and geo-temperature gradients. Finally, the present gas generation condition of the Permian coal measure is discussed by associating with the temperature condition, the vitrinite reflectance (Ro), the metamorphism of coal and tectonic-burial evolution. The study indicates all present characters of the Permian coal measure, such as lower present temperature, higher Ro value, middle-high rank coals, and uplift and extension events after the coal measure sediment, are favorable for the generation of secondary biogenic gas, but not thermogenic gas or primary biogenic gas.

  15. Furnace and Heat Recovery Area Design and Analysis for Conceptual Design of Supercritical O2-Based PC Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Seltzer

    2006-05-01

    The objective of the furnace and heat recovery area design and analysis task of the Conceptual Design of Supercritical Oxygen-Based PC Boiler study is to optimize the location and design of the furnace, burners, over-fire gas ports, and internal radiant surfaces. The furnace and heat recovery area were designed and analyzed using the FW-FIRE, Siemens, and HEATEX computer programs. The furnace is designed with opposed wall-firing burners and over-fire air ports. Water is circulated in the furnace by forced circulation to the waterwalls at the periphery and divisional wall panels within the furnace. Compared to the air-fired furnace, the oxygen-fired furnace requires only 65% of the surface area and 45% of the volume. Two oxygen-fired designs were simulated: (1) with cryogenic air separation unit (ASU) and (2) with oxygen ion transport membrane (OITM). The maximum wall heat flux in the oxygen-fired furnace is more than double that of the air-fired furnace due to the higher flame temperature and higher H{sub 2}O and CO{sub 2} concentrations. The coal burnout for the oxygen-fired case is 100% due to a 500 F higher furnace temperature and higher concentration of O{sub 2}. Because of the higher furnace wall temperature of the oxygen-fired case compared to the air-fired case, furnace water wall material was upgraded from T2 to T92. Compared to the air-fired heat recovery area (HRA), the oxygen-fired HRA total heat transfer surface is 35% less for the cryogenic design and 13% less for the OITM design due to more heat being absorbed in the oxygen-fired furnace and the greater molecular weight of the oxygen-fired flue gas. The HRA tube materials and wall thickness are nearly the same for the air-fired and oxygen-fired design since the flue gas and water/steam temperature profiles encountered by the heat transfer banks are similar.

  16. Furnace and Heat Recovery Area Design and Analysis for Conceptual Design of Supercritical O2-Based PC Boiler

    International Nuclear Information System (INIS)

    The objective of the furnace and heat recovery area design and analysis task of the Conceptual Design of Supercritical Oxygen-Based PC Boiler study is to optimize the location and design of the furnace, burners, over-fire gas ports, and internal radiant surfaces. The furnace and heat recovery area were designed and analyzed using the FW-FIRE, Siemens, and HEATEX computer programs. The furnace is designed with opposed wall-firing burners and over-fire air ports. Water is circulated in the furnace by forced circulation to the waterwalls at the periphery and divisional wall panels within the furnace. Compared to the air-fired furnace, the oxygen-fired furnace requires only 65% of the surface area and 45% of the volume. Two oxygen-fired designs were simulated: (1) with cryogenic air separation unit (ASU) and (2) with oxygen ion transport membrane (OITM). The maximum wall heat flux in the oxygen-fired furnace is more than double that of the air-fired furnace due to the higher flame temperature and higher H2O and CO2 concentrations. The coal burnout for the oxygen-fired case is 100% due to a 500 F higher furnace temperature and higher concentration of O2. Because of the higher furnace wall temperature of the oxygen-fired case compared to the air-fired case, furnace water wall material was upgraded from T2 to T92. Compared to the air-fired heat recovery area (HRA), the oxygen-fired HRA total heat transfer surface is 35% less for the cryogenic design and 13% less for the OITM design due to more heat being absorbed in the oxygen-fired furnace and the greater molecular weight of the oxygen-fired flue gas. The HRA tube materials and wall thickness are nearly the same for the air-fired and oxygen-fired design since the flue gas and water/steam temperature profiles encountered by the heat transfer banks are similar

  17. Historic and future increase in the global land area affected by monthly heat extremes

    International Nuclear Information System (INIS)

    Climatic warming of about 0.5 ° C in the global mean since the 1970s has strongly increased the occurrence-probability of heat extremes on monthly to seasonal time scales. For the 21st century, climate models predict more substantial warming. Here we show that the multi-model mean of the CMIP5 (Coupled Model Intercomparison Project) climate models accurately reproduces the evolution over time and spatial patterns of the historically observed increase in monthly heat extremes. For the near-term (i.e., by 2040), the models predict a robust, several-fold increase in the frequency of such heat extremes, irrespective of the emission scenario. However, mitigation can strongly reduce the number of heat extremes by the second half of the 21st century. Unmitigated climate change causes most (>50%) continental regions to move to a new climatic regime with the coldest summer months by the end of the century substantially hotter than the hottest experienced today. We show that the land fraction experiencing extreme heat as a function of global mean temperature follows a simple cumulative distribution function, which depends only on natural variability and the level of spatial heterogeneity in the warming. (letter)

  18. Impacts of Irrigation on the Heat Fluxes and Near-Surface Temperature in an Inland Irrigation Area of Northern China

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2014-03-01

    Full Text Available Irrigated agriculture has the potential to alter regional to global climate significantly. We investigate how irrigation will affect regional climate in the future in an inland irrigation area of northern China, focusing on its effects on heat fluxes and near-surface temperature. Using the Weather Research and Forecasting (WRF model, we compare simulations among three land cover scenarios: the control scenario (CON, the irrigation scenario (IRR, and the irrigated cropland expansion scenario (ICE. Our results show that the surface energy budgets and temperature are sensitive to changes in the extent and spatial pattern of irrigated land. Conversion to irrigated agriculture at the contemporary scale leads to an increase in annual mean latent heat fluxes of 12.10 W m−2, a decrease in annual mean sensible heat fluxes of 8.85 W m−2, and a decrease in annual mean temperature of 1.3 °C across the study region. Further expansion of irrigated land increases annual mean latent heat fluxes by 18.08 W m−2, decreases annual mean sensible heat fluxes by 12.31 W m−2, and decreases annual mean temperature by 1.7 °C. Our simulated effects of irrigation show that changes in land use management such as irrigation can be an important component of climate change and need to be considered together with greenhouse forcing in climate change assessments.

  19. Sensitivity of large-aperture scintillometer measurements of area-average heat fluxes to uncertainties in topographic heights

    Directory of Open Access Journals (Sweden)

    M. A. Gruber

    2014-01-01

    Full Text Available Scintillometer measurements allow for estimations of the refractive index structure parameter Cn2 over large areas in the atmospheric surface layer. Turbulent fluxes of heat and momentum are inferred through coupled sets of equations derived from the Monin–Obukhov similarity hypothesis. One-dimensional sensitivity functions have been produced that relate the sensitivity of heat fluxes to uncertainties in single values of beam height over homogeneous and flat terrain. However, real field sites include variable topography and heterogeneous surfaces. We develop here the first analysis of the sensitivity of scintillometer derived sensible heat fluxes to uncertainties in spatially distributed topographic measurements. For large-aperture scintillometers and independent friction velocity u* measurements, sensitivity is shown to be concentrated in areas near the center of the beam path and where the underlying topography is closest to the beam height. Uncertainty may be greatly reduced by focusing precise topographic measurements in these areas. A new two-dimensional variable terrain sensitivity function is developed for quantitative error analysis. This function is compared with the previous one-dimensional sensitivity function for the same measurement strategy over flat and homogeneous terrain. Additionally, a new method of solution to the set of coupled equations is produced that eliminates computational error. The results are produced using a new methodology for error analysis involving distributed parameters that may be applied in other disciplines.

  20. São Paulo urban heat islands have a higher incidence of dengue than other urban areas

    Directory of Open Access Journals (Sweden)

    Ricardo Vieira Araujo

    2015-04-01

    Full Text Available Urban heat islands are characterized by high land surface temperature, low humidity, and poor vegetation, and considered to favor the transmission of the mosquito-borne dengue fever that is transmitted by the Aedes aegyptimosquito. We analyzed the recorded dengue incidence in Sao Paulo city, Brazil, in 2010-2011, in terms of multiple environmental and socioeconomic variables. Geographical information systems, thermal remote sensing images, and census data were used to classify city areas according to land surface temper- ature, vegetation cover, population density, socioeconomic status, and housing standards. Of the 7415 dengue cases, a majority (93.1% mapped to areas with land surface temperature >28 ◦ C. The dengue incidence rate (cases per 100,000 inhabitants was low (3.2 cases in high vegetation cover areas, but high (72.3 cases in low vegetation cover areas where the land surface temperature was 29 ± 2 ◦ C. Interestingly, a multiple cluster analysis phenogram showed more dengue cases clustered in areas of land surface temperature >32 ◦ C, than in areas characterized as low socioeconomic zones, high population density areas, or slum-like areas. In laboratory experiments, A. aegyptimosquito larval development, blood feeding, and oviposition associated positively with temperatures of 28-32 ◦ C, indicating these temperatures to be favorable for dengue transmission. Thus, among all the variables studied, dengue incidence was most affected by the temperature.

  1. Urban Heat Island Variation across a Dramatic Coastal to Desert Climate Zone: An Application to Los Angeles, CA Metropolitan Area

    Science.gov (United States)

    Tayyebi, A.; Jenerette, D.

    2015-12-01

    Urbanization is occurring at an unprecedented rate across the globe. The resulting urban heat island (UHI), which is a well-known phenomenon in urban areas due to the increasing number and density of buildings, leads to higher temperature in urban areas than surrounding sub-urban or rural areas. Understanding the effects of landscape pattern on UHI is crucial for improving the sustainability of cities and reducing heat vulnerability. Although a variety of studies have quantified UHI, there are a lack of studies to 1) understand UHI variation at the micro-scale (e.g., neighborhood effect) for large urban areas and 2) identify variation in the sensitivity of the UHI to environmental drivers across a megacity with a pronounced climate zone (i.e. coastal to desert climates) using advanced analytical tools. In this study, we identified the interacting relationship among various environmental and socio-economic factors to better identify UHI over the Los Angeles, CA metropolitan area. We used structural equation modeling (SEM) to quantify the interacting relationships among land surface temperature (LST), land cover (NDVI), distance to ocean, elevation, and socio-economic status (neighborhood income). LST-NDVI slopes were negative across the climate zones and became progressively stronger with increasing distance from the coast. Results also showed that slopes between NDVI and neighborhood income were positive throughout the climate zone with a maximum in the relationship occurring near 25km from the coast. Because of these income-NDVI and NDVI-LST relationships we also found that slopes between LST and neighborhood income were negative throughout the climate zones and peaked at about 30km from the coast. These findings suggest assessments of urban heat vulnerability need to consider not only variation in the indicators but also variation in how the indicators influence vulnerability.

  2. Dynamics of Soil Heat Flux in Lowland Area: Estimating the Soil Thermal Conductivy

    Science.gov (United States)

    Zimmer, T.; Silveira, M. V.; Roberti, D. R.

    2013-05-01

    In this work, it is shown soil thermal conductivity estimates in a flooded irrigated rice culture located at the Paraíso do Sul city for two distinct periods. The thermal conductivity is higher when the heat storage is higher and the soil surface temperature is lower. The soil thermal conductivity is also dependant on the soil texture, porosity and moisture. Therefore, it varies from soil to soil and in the same soil, depending on its soil moisture. For approximately 80% of its growing season, lowland flooded irrigated rice ecosystems stay under a 5 - 10 cm water layer. It affects the partitioning of the energy and water balance components. Furthermore this planting technique differs substantially from any other upland non-irrigated or irrigated crop ecosystems where the majority of observational studies have been conducted. In the present work, the dynamic of soil heat flux (G) is analyzed and the soil thermal conductivity (Ks) is estimated using experimental data form soil heat flux and soil temperature in a rice paddy farm in a subtropical location in Southern Brazil. In this region, rice grows once a year at river lowlands and wetlands while the ground is kept bare during the remaining of the year. The soil type is Planossolo Hidromórfico Distrófico, characterized as a mix between sandy and clay soil. The soil heat flux (G) was experimentally estimated with the sensor Hukseflux (HFP01SC-L) at 7 cm bellow the soil surface. The soil temperature at 5 cm and 10 cm was experimentally estimated using the sensor STP01. The experimental soil heat flux was compared with estimated soil heat flux by two forms: (1) using a know Ks from literature for this type of soil in saturated conditions (Ks=1.58); (2) using Ks estimated using the inversion of the equation Qg=-ks* ((T10-T5)/ (Z2-Z1)), where T10 and T5 are the temperature in 10 and 5 cm above the soil and Z2-Z1 is the difference between the positions in temperature measurement. The study period for estimating the Ks

  3. Contribution of Low-Frequency Motions to Sensible Heat Fluxes over Urban and Suburban Areas

    Science.gov (United States)

    Zhang, He; Zhang, Hongsheng; Cai, Xuhui; Song, Yu; Sun, Jianning

    2016-10-01

    Field observations of the atmospheric boundary layer were made over urban and suburban terrain in the Yangtze River Delta, China. A multiresolution decomposition was applied over three different types of terrain: flat homogeneous terrain, suburban terrain and urban terrain, with results indicating that, (1) the average scale contribution of u, v, w and Tv had a similar variability with length scale for all these three sites respectively, and the dimensionless length scale corresponding to the maximum sensible heat flux contribution increased with the terrain complexity; (2) the length scale corresponding to the maximal average scale contribution for vertical wind velocity λ _w was directly proportional to the roughness length z0 in unstable conditions; and (3) the contributions of large-scale motions led to sensible heat fluxes determined with a large-aperture scintillomter being larger than those using the eddy-covariance method for the suburban case, whereas this phenomenon was not substantial for the urban case.

  4. Contribution of Low-Frequency Motions to Sensible Heat Fluxes over Urban and Suburban Areas

    Science.gov (United States)

    Zhang, He; Zhang, Hongsheng; Cai, Xuhui; Song, Yu; Sun, Jianning

    2016-06-01

    Field observations of the atmospheric boundary layer were made over urban and suburban terrain in the Yangtze River Delta, China. A multiresolution decomposition was applied over three different types of terrain: flat homogeneous terrain, suburban terrain and urban terrain, with results indicating that, (1) the average scale contribution of u, v, w and Tv had a similar variability with length scale for all these three sites respectively, and the dimensionless length scale corresponding to the maximum sensible heat flux contribution increased with the terrain complexity; (2) the length scale corresponding to the maximal average scale contribution for vertical wind velocity λ _w was directly proportional to the roughness length z0 in unstable conditions; and (3) the contributions of large-scale motions led to sensible heat fluxes determined with a large-aperture scintillomter being larger than those using the eddy-covariance method for the suburban case, whereas this phenomenon was not substantial for the urban case.

  5. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana;

    2016-01-01

    and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... to the theoretical value. The optimal solutions corresponding to the theoretical and the practical upper bound values for the total heat transfer area (100 m2 and 61 m2, respectively) as well as the optimal solution obtained by minimization of the total annual cost are discussed for a case study considering...... exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...

  6. An economic optimization of evaporator and air collector area in a solar assisted heat pump drying system

    International Nuclear Information System (INIS)

    Highlights: • The optimum combination will provide around 89% of the total load. • The system has a savings during the life cycle with least payback period of 4.37 year. • The optimal system is insensitive to the variation in fuel inflation and discount rate. - Abstract: This paper presents an economic optimization of evaporator and air collector area of a solar assisted heat pump drying system. Economic viability of solar heating systems is usually made by comparing the cost flows recurring throughout the lifetime of the solar and conventional alternative systems. Therefore, identification of optimum variables by using a simulation program and an economic analysis based on payback period of the system are presented in this paper. FORTRAN language is used to run the simulation. Effect of load and different economic variables on payback period is also investigated. Economic analysis reveals that system has sufficient amount of savings during the life cycle with a minimum payback period of about 4 years

  7. Space and time variability of heating requirements for greenhouse tomato production in the Euro-Mediterranean area.

    Science.gov (United States)

    Mariani, Luigi; Cola, Gabriele; Bulgari, Roberta; Ferrante, Antonio; Martinetti, Livia

    2016-08-15

    The Euro-Mediterranean area is the seat of a relevant greenhouse activity, meeting the needs of important markets. A quantitative assessment of greenhouse energy consumption and of its variability in space and time is an important decision support tool for both greenhouse-sector policies and farmers. A mathematical model of greenhouse energy balance was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for vegetables growing. Tomato was adopted as reference crop, due to its high energy requirement for fruit setting and ripening and its economic relevance. In order to gain a proper description of the Euro-Mediterranean area, 56 greenhouse areas located within the ranges 28°N-72°N and 11°W-55°E were analyzed over the period 1973-2014. Moreover, the two 1973-1987 and 1988-2014 sub-periods were separately studied to describe climate change effects on energy consumption. Results account for the spatial variability of energy needs for tomato growing, highlighting the strong influence of latitude on the magnitude of heat requirements. The comparison between the two selected sub-periods shows a decrease of energy demand in the current warm phase, more relevant for high latitudes. Finally, suggestions to reduce energy consumptions are provided. PMID:27110994

  8. Space and time variability of heating requirements for greenhouse tomato production in the Euro-Mediterranean area.

    Science.gov (United States)

    Mariani, Luigi; Cola, Gabriele; Bulgari, Roberta; Ferrante, Antonio; Martinetti, Livia

    2016-08-15

    The Euro-Mediterranean area is the seat of a relevant greenhouse activity, meeting the needs of important markets. A quantitative assessment of greenhouse energy consumption and of its variability in space and time is an important decision support tool for both greenhouse-sector policies and farmers. A mathematical model of greenhouse energy balance was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for vegetables growing. Tomato was adopted as reference crop, due to its high energy requirement for fruit setting and ripening and its economic relevance. In order to gain a proper description of the Euro-Mediterranean area, 56 greenhouse areas located within the ranges 28°N-72°N and 11°W-55°E were analyzed over the period 1973-2014. Moreover, the two 1973-1987 and 1988-2014 sub-periods were separately studied to describe climate change effects on energy consumption. Results account for the spatial variability of energy needs for tomato growing, highlighting the strong influence of latitude on the magnitude of heat requirements. The comparison between the two selected sub-periods shows a decrease of energy demand in the current warm phase, more relevant for high latitudes. Finally, suggestions to reduce energy consumptions are provided.

  9. Heat transfer and material temperature conditions in the leading edge area of impingement-cooled turbine vanes

    Science.gov (United States)

    Berg, H. P.; Pfaff, K.; Hennecke, D. K.

    The resultant effects on the cooling effectiveness at the leading edge area of an impingement-cooled turbine vane by varying certain geometrical parameters is described with reference to local internal heat transfer coefficients determined from experiment and temperature calculations. The local heat transfer on the cooling-air side is determined experimentally with the aid of the analogy between heat- and mass transfer. The impingement cooling is provided from an inserted sheet-metal containing a single row of holes. The Reynolds Number and several of the cooling geometry parameters were varied. The results demonstrate the high local resolution of the method of measurement, which allows improved analytical treatment of the leading-edge cooling configuration. These experiments also point to the necessity of not always performing model tests under idealized conditions. This becomes very clear in the case of the tests performed on an application-oriented impingement-cooling configuration like that often encountered in engine manufacture. In conclusion, as an example, temperature calculations are employed to demonstrate the effect on the cooling effectiveness of varying the distances between insert and inner surface of the leading edge. It shows how the effectiveness of the leading edge cooling can be increased by simple geometrical measures, which results in a considerable improvement in service life.

  10. The Area of Secondary Hyperalgesia following Heat Stimulation in Healthy Male Volunteers: Inter- and Intra-Individual Variance and Reproducibility.

    Directory of Open Access Journals (Sweden)

    Morten Sejer Hansen

    Full Text Available Clinical pain models can be applied when investigating basic physiologic pain responses in healthy volunteers. Several pain models exist; however, only few have been adequately validated. Our primary aim with this prospective study was to investigate the intra- and inter-individual variation in secondary hyperalgesia elicited by brief thermal sensitization (45°C for 3 min in healthy volunteers.Fifty healthy volunteers were included. Areas of secondary hyperalgesia following brief thermal sensitization were investigated by 2 observers on 4 experimental days, with a minimum interval of 7 days. Additionally, heat pain detection threshold and pain during thermal stimulation (45°C for 1 min., and the psychological tests Pain Catastrophizing Scale and Hospital Anxiety and Depression Score were applied.For areas of secondary hyperalgesia, an intra-observer intra-person correlation of 0.85, 95% CI [0.78, 0.90], an intra-observer inter-person correlation of 0.03, 95% CI [0.00, 0.16], and a coefficient of variation of 0.17, 95% CI [0.14, 0.21] was demonstrated. Four percent of the study population had areas of secondary hyperalgesia both below the 1st and above the 3rd quartile considering all included participants. Heat pain detection threshold predicted area of secondary hyperalgesia with an adjusted R2 of 0.20 (P = 0.0006.We have demonstrated a low intra-individual, and a high inter-individual variation in thermally induced secondary hyperalgesia. We conclude that brief thermal sensitization produce secondary hyperalgesia with a high level of reproducibility, which can be applied to investigate different phenotypes related to secondary hyperalgesia in healthy volunteers.clinicaltrials.gov NCT02166164.

  11. Spatio-Temporal Analysis of Urban Heat Island and Urban Metabolism by Satellite Imagery over the Phoenix Metropolitan Area

    Science.gov (United States)

    Zhao, Q.; Zhan, S.; Kuai, X.; Zhan, Q.

    2015-12-01

    The goal of this research is to combine DMSP-OLS nighttime light data with Landsat imagery and use spatio-temporal analysis methods to evaluate the relationships between urbanization processes and temperature variation in Phoenix metropolitan area. The urbanization process is a combination of both land use change within the existing urban environment as well as urban sprawl that enlarges the urban area through the transformation of rural areas to urban structures. These transformations modify the overall urban climate environment, resulting in higher nighttime temperatures in urban areas compared to the surrounding rural environment. This is a well-known and well-studied phenomenon referred to as the urban heat island effect (UHI). What is unknown is the direct relationship between the urbanization process and the mechanisms of the UHI. To better understand this interaction, this research focuses on using nighttime light satellite imagery to delineate and detect urban extent changes and utilizing existing land use/land cover map or newly classified imagery from Landsat to analyze the internal urban land use variations. These data are combined with summer and winter land surface temperature data extracted from Landsat. We developed a time series of these combined data for Phoenix, AZ from 1992 to 2013 to analyze the relationships among land use change, land surface temperature and urban growth.

  12. Heat supply to low energy dwellings in district heating areas. Analyses of CO{sub 2} emissions and electricity supply security; Varmeforsyning til lavenergiboliger i omraader med fjernvarmekonsesjon. Analyser av CO{sub 2}-utslipp og forsyningssikkerhet for elektrisitet

    Energy Technology Data Exchange (ETDEWEB)

    Thyholt, Marit

    2006-07-01

    Building low energy dwellings in large development projects is a new situation in Norway. The municipalities have to a little extent analyzed the consequences of this new housing standard with respect to the energy supply to such areas, and how this standard may change the plans for new or extended district heat production. In the provision about the mandatory connection to district heating plants, and the appendant provision related to a heating system that can utilize district heat, the district heat supply and the heat demand are not seen in connection. The objective of this dissertation is to provide the municipalities with a basis for decision making in the processing of applications concerning dispensation from the mandatory connection or the heating system requirement for dwellings with low heat demand. This basis for decision making is based on the national aim of reducing carbon dioxide (CO{sub 2}) emissions and of improving the electricity supply security. This summary provides an abstract from the discussion of the legislation as an incentive or barrier for building low energy dwellings. An abstract from a survey among construction firms concerning the motivation for building low energy dwellings is also included. In addition, the summary provides a comprehensive abstract of the results from the CO{sub 2} emission calculations, and the basis for these calculations. Introductorily a brief background of the national focus on energy savings and increased use of hydronic heating, including district heat, is given.

  13. Heating, current drive and transport properties of large area ICRF couplers

    International Nuclear Information System (INIS)

    Initially, the large area ICRF couplers were studied in Macrotor in order to minimize the effects of the RF on the edge plasma and on the related transport. Recently, the following three aspects of these couplers have been studied. (1) Reduction of the edge power density by size alone. (2) Formation of a narrow K-parallel spectrum. (3) The utilization of this powerful technique for fast wave lower hybrid current drive generation. Current drive experiments in Macrotor have resulted in the prediction that a continuously driven tokamak operation can be achieved at a level that will be consistent with neo-Alcator scaling

  14. The impact of green areas in mitigation of urban heat island

    Science.gov (United States)

    Zaninovic, Ksenija

    2016-04-01

    In the framework of the project REPUBLICMED (REtroffiting PUBLic spaces in Intelligent MEDiterranean Cities) co-financed by the European Union, the changes in urban structure have to be proposed in order to mitigate the urban heat island in Zadar, Croatia. The intention is to compare thermal perception for selected locations in Zadar in the present situation and after proposed changes in different parts of the year. For that purpose, four days in different seasons were selected. For winter and summer, the days with extreme minimum and maximum temperatures were selected, whilst for spring and autumn the days in the middle of seasons (April and October) with mean temperatures similar to the corresponding mean seasonal temperatures were selected. All selected days were mainly clear or with small cloudiness resulting with maximum solar radiation. The thermal perception was calculated by means of biometeorological index based on energy equilibrium between human body and environment - physiologically equivalent temperature (PET). In the first analysis, daily courses of biometeorological index for selected situations based on hourly data were compared. During warmest parts of the day in summer the thermal perception differs up to 5°C under the tree shadow, while the differences in other seasons are smaller. The second analysis included the differences in the distribution of frequencies of thermal perception in the warmest part of the day (2 p.m.) throughout the year for selected locations. It is performed using meteorological data measured at the meteorological station Zadar in the 30-year climate period 1981-2010. The results have revealed the reduction in the frequency of sensations of hot and very hot (PET > 35°C or 41°C) under the shadow of the trees during summer, at the rate of up to 25% comparing to the situation before modification (without trees).

  15. The Application Advantage of Heat-source-tower Heat Pump in Hot Summer and Cold Winter Area%热源塔热泵在夏热冬暖地区的应用优势

    Institute of Scientific and Technical Information of China (English)

    许国强; 黄德祥; 张旭东

    2016-01-01

    The heat-source-tower heat pump technology is briefly introduced in this paper,comparative analyzed the heat-source-tower heat pump technology and the traditional heating in hot summer and warm winter area,it believe that the heat-source-tower heat pump technology has advantage application in the hot summer and warm winter area,it has the lowest cost in the whole life cycle,is a kind of new heat pump air conditioning system which is a energy saving and environmental protection type.%本文对热源塔热泵技术作了简要介绍,将热源塔热泵技术与夏热冬暖地区传统空调供暖方式进行比较分析,认为热源塔热泵技术在夏热冬暖地区有其应用优势,全寿命周期内费用最低,运行稳定,是一种新的节能、环保类热泵空调形式。

  16. Numerical climate modeling and verification of selected areas for heat waves of Pakistan using ensemble prediction system

    Science.gov (United States)

    Amna, S.; Samreen, N.; Khalid, B.; Shamim, A.

    2013-06-01

    Depending upon the topography, there is an extreme variation in the temperature of Pakistan. Heat waves are the Weather-related events, having significant impact on the humans, including all socioeconomic activities and health issues as well which changes according to the climatic conditions of the area. The forecasting climate is of prime importance for being aware of future climatic changes, in order to mitigate them. The study used the Ensemble Prediction System (EPS) for the purpose of modeling seasonal weather hind-cast of three selected areas i.e., Islamabad, Jhelum and Muzaffarabad. This research was purposely carried out in order to suggest the most suitable climate model for Pakistan. Real time and simulated data of five General Circulation Models i.e., ECMWF, ERA-40, MPI, Meteo France and UKMO for selected areas was acquired from Pakistan Meteorological Department. Data incorporated constituted the statistical temperature records of 32 years for the months of June, July and August. This study was based on EPS to calculate probabilistic forecasts produced by single ensembles. Verification was done out to assess the quality of the forecast t by using standard probabilistic measures of Brier Score, Brier Skill Score, Cross Validation and Relative Operating Characteristic curve. The results showed ECMWF the most suitable model for Islamabad and Jhelum; and Meteo France for Muzaffarabad. Other models have significant results by omitting particular initial conditions.

  17. Study on hybrid ground-coupled heat pump system for air-conditioning in hot-weather areas like Hong Kong

    International Nuclear Information System (INIS)

    The ground-coupled heat pump (GCHP) system is becoming attractive for air-conditioning in some moderate-weather regions due to its high energy efficiency and reliable operation capability. However, when the technology is used in buildings where there is only cooling load in hot-weather areas like Hong Kong, the heat rejected into the ground by the GCHP systems will accumulate around the ground heat exchangers (GHE). This heat accumulation will result in degradation of system performance and increment of system operating costs. This problem can be resolved by using the hybrid ground-coupled heat pump (HGCHP) system, which uses supplemental heat rejecters to reject the accumulated heat. This paper presents a practical hourly simulation model of the HGCHP system by modeling the heat transfer process of the system's main components. The computer program based on this hourly simulation model can be used to calculate the hour-by-hour operation data of the HGCHP system. As a case study, both a HGCHP system and a traditional GCHP system are designed for a hypothetic private residential building located in Hong Kong, and the economic comparisons are conducted between these two types of systems. The simulation results show that the HGCHP system can effectively solve the heat accumulation problem and reduce both the initial costs and operating costs of the air-conditioning system in the building.

  18. Severe Weather Caused by Heat Island and Sea Breeze Effects in the Metropolitan Area of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Felipe Vemado

    2016-01-01

    Full Text Available The Metropolitan Area of São Paulo (MASP is one of the most populated regions of the planet with one of the largest impervious regions as well. This research work aims to characterize MASP heat island (HI effect and its interaction with the local sea breeze (SB inflow in rainfall amounts and deep convection. The combined SB-HI produces direct circulation over the MASP and produces severe weather and socioeconomic impacts. All SB-HI episodes between 2005 and 2008 are identified and analyzed with surface and upper air measurements, weather radar, and satellite data. The current work indicates that intense SB-HI episodes are related to air and dew point temperatures above 30°C and 20°C, respectively, right after the passage of the SB front over MASP. Results indicate that the precipitation related to SB-HI episodes is up to 600 mm or about four times higher than that in rural or less urbanized areas in its surroundings. Measurements indicate that 74% of SB-HI episodes are related to NW winds in earlier afternoon hours. Moving cold fronts in southern Brazil tend to intensify the SB-HI circulation in MASP. A conceptual model of these patterns is presented in this paper.

  19. Validation of ASTER Surface Temperature Data with In Situ Measurements to Evaluate Heat Islands in Complex Urban Areas

    Directory of Open Access Journals (Sweden)

    Bonggeun Song

    2014-01-01

    Full Text Available This study compared Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER surface temperature data with in situ measurements to validate the use of ASTER data for studying heat islands in urban settings with complex spatial characteristics. Eight sites in Changwon, Korea, were selected for analyses. Surface temperature data were extracted from the thermal infrared (TIR band of ASTER on four dates during the summer and fall of 2012, and corresponding in situ measurements of temperature were also collected. Comparisons showed that ASTER derived temperatures were generally 4.27°C lower than temperatures collected by in situ measurements during the daytime, except on cloudy days. However, ASTER temperatures were higher by 2.23–2.69°C on two dates during the nighttime. Temperature differences between a city park and a paved area were insignificant. Differences between ASTER derived temperatures and onsite measurements are caused by a variety of factors including the application of emissivity values that do not consider the complex spatial characteristics of urban areas. Therefore, to improve the accuracy of surface temperatures extracted from infrared satellite imagery, we propose a revised model whereby temperature data is obtained from ASTER and emissivity values for various land covers are extracted based on in situ measurements.

  20. Development of oxidation heat of the coal left in the mined-out area of a longwall face: Modelling using the fluent software

    Directory of Open Access Journals (Sweden)

    Taraba B.

    2008-01-01

    Full Text Available A commercial CFD software program, Fluent, was used to study oxidation processes in the longwall mined-out (gob area. A three-dimensional model of the gob area with an advancing coal face has been developed. For the model, typical oxidation behavior of a bituminous coal from the Ostrava-Karviná District was incorporated as resulted from laboratory investigations. The longwall gob area was designed on the basis of the actual longwall face district. Detailed measurements in the district then enabled re-verification of the model outputs with actual data in situ. The main attention was paid to modelling the effect of grain size of the coal left in the mined-out area on the oxidation heat and gases evolution. Numerical simulations confirmed the existence of an 'optimal' zone for intense development of the spontaneous heating process in the gob area.

  1. 重庆地区地表水地源热泵系统冬季供暖工程应用%Engineering application of surface water source heat pump for winter heating in Chongqing area

    Institute of Scientific and Technical Information of China (English)

    卢军; 黄俊杰; 廖兴中

    2013-01-01

    Tests the heating operating conditions of five surface water source heat pump projects in Chongqing area,and compares them with those of the air source heat pump and boiler heating mode.The results show that the heating coefficient of performance (COP) of the river water source heat pump unit reaches 2.8 to 5.3 and the heating energy efficiency ratio (EER) reaches 2.7 to 4.3,and the COP and EER of the lake water source heat pump system reach 4.4 and 3.0 respectively; the indoor temperature and relative humidity can be maintained about 20℃ and above 40% respectively; the improving rates in energy efficiency of a surface water source heat pump system for winter heating are respectively 8.0% to 72.0%and 18.0% to 87.9% compared with the air source heat pump and boiler heating,and energy saving is significant.%以重庆地区5个地表水地源热泵项目为例,对其冬季供暖运行工况进行了实测,并与空气源热泵和锅炉供暖进行了比较.结果表明,江水源热泵系统的机组制热性能系数COP和系统制热能效比EER分别能达到2.8~5.3和2.7~4.3,湖水源热泵系统的COP和EER分别能达到4.4和3.0,并且室内温度和相对湿度分别能保持在20℃左右和40%以上;相比于空气源热泵和锅炉供暖,地表水地源热泵系统冬季供暖的能效提高率分别达到了8.0%~72.0%和18.0%~87.9%,节能显著.

  2. The diurnal and seasonal characteristics of urban heat island variation in Beijing city and surrounding areas and impact factors based on remote sensing satellite data

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jiahua; HOU; Yingyu; LI; Guicai; YAN; Hao; YANG; Lim

    2005-01-01

    Based on the land surface temperature (LST), the land cover classification map,vegetation coverage, and surface evapotranspiration derived from EOS-MODIS satellite data, and by the use of GIS spatial analytic technique and multivariate statistical analysis method, the urban heat island (UHI) spatial distribution of the diurnal and seasonal variabilities and its driving forces are studied in Beijing city and surrounding areas in 2001. The relationships among UHI distribution and landcover categories, topographic factor, vegetation greenness, and surface evapotranspiration are analyzed. The results indicate that: (i) The significant UHI occur in Beijing city areas in the four seasons due to high heat capacity and multi-reflection of compression building, as well as with special topographic features of its three sides surrounded by mountains,especially in the summer. The UHI spatial distribution is corresponding with the urban geometry structure profile. The LST difference is approximately 4-6℃ between Beijing city and suburb areas, comparatively is 8- 10℃ between Beijing city area and outer suburb area in northwestern regions. (ii) The UHI distribution and intensity in daytime are different from nighttime in Beijing city area, the nighttime UHI is obvious. However, in the daytime, the significant UHI mainly appears in the summer, the autumn takes second place, and the UHI in the winter and the spring seem not obvious. The surface evapotranspiration in suburb areas is larger than that in urban areas in the summer, and high latent heat exchange is evident, which leads to LST difference between city area and suburb area. (iii) The reflection of surface landcover categories is sensitive to the UHI, the correlation between vegetation greenness and UHI shows obviously negative.The scatterplot shows that there is the negative correlation between NDVI and LST (R2 = 0.6481).The results demonstrate that the vegetation greenness is an important factor for reducing the UHI

  3. The contribution of urbanization to recent extreme heat events and white roof mitigation strategy in the Beijing-Tianjin-Hebei metropolitan area

    Science.gov (United States)

    Wang, Mingna

    2015-04-01

    The UHI effect can aggravate summertime heat waves and strongly influence human comfort and health, leading to greater mortality in metropolitan areas. Many geo-engineering technological strategies have been proposed to mitigate climate warming, and for the UHI, increasing the albedo of artificial urban surfaces (rooftops or pavements) has been considered a lucrative and effective way to cool cities. The objective of this work is to quantify the contribution of urbanization to recent extreme heat events of the early 21st century in the Beijing-Tianjin-Hebei metropolitan area, using the mesoscale WRF model coupled with a single urban canopy model and actual urban land cover datasets. This work also investigates a simulation of the regional effects of white roof technology by increasing the albedo of urban areas in the urban canopy model to mitigate the urban heat island, especially in extreme heat waves. The results show that urban land use characteristics that have evolved over the past ~20 years in the Beijing-Tianjin-Hebei metropolitan area have had a significant impact on the extreme temperatures occurring during extreme heat events. Simulations show that new urban development has caused an intensification and expansion of the areas experiencing extreme heat waves with an average increase in temperature of approximately 0.60°C. This change is most obvious at night with an increase up to 0.95°C, for which the total contribution of anthropogenic heat is 34%. We also simulate the effects of geo-engineering strategies increasing the albedo of urban roofs. White roofs reflect a large fraction of incoming sunlight in the daytime, which reduced the net radiation so that the roof surface keep at a lower temperature than regular solar-absorptive roofs. Urban net radiation decreases by approximately 200 W m-2 at local noon because of high solar reflectance of white roofs, which cools the daytime urban temperature afer sunrise, with the largest decrease of almost -0.80

  4. High Concentration of Heat Pumps in Suburban Areas and Reduction of Their Impact on the Electricity Network

    NARCIS (Netherlands)

    Pruissen, O.P. van; Kamphuis, I.G.

    2011-01-01

    One of the challenges of the near future for a more renewable Dutch electricity infrastructure is the embedding of high concentrations of heat pumps in currently built domestic residences. In the Dutch situation demand of electricity occurs simultaneously with demand of heat, high electricity peak l

  5. Arctic layer salinity controls heat loss from deep Atlantic layer in seasonally ice-covered areas of the Barents Sea

    Science.gov (United States)

    Lind, Sigrid; Ingvaldsen, Randi B.; Furevik, Tore

    2016-05-01

    In the seasonally ice-covered northern Barents Sea an intermediate layer of cold and relatively fresh Arctic Water at ~25-110 m depth isolates the sea surface and ice cover from a layer of warm and saline Atlantic Water below, a situation that resembles the cold halocline layer in the Eurasian Basin. The upward heat flux from the Atlantic layer is of major concern. What causes variations in the heat flux and how is the Arctic layer maintained? Using observations, we found that interannual variability in Arctic layer salinity determines the heat flux from the Atlantic layer through its control of stratification and vertical mixing. A relatively fresh Arctic layer effectively suppresses the upward heat flux, while a more saline Arctic layer enhances the heat flux. The corresponding upward salt flux causes a positive feedback. The Arctic layer salinity and the water column structures have been remarkably stable during 1970-2011.

  6. A study of the hourly variability of the urban heat island effect in the Greater Athens Area during summer.

    Science.gov (United States)

    Kourtidis, K; Georgoulias, A K; Rapsomanikis, S; Amiridis, V; Keramitsoglou, I; Hooyberghs, H; Maiheu, B; Melas, D

    2015-06-01

    Measurements of air temperature and humidity in the urban canopy layer during July 2009 in 26 sites in Athens, Greece, allowed for the mapping of the hourly spatiotemporal evolution of the urban heat island (UHI) effect. City districts neighboring to the mountains to the east were the hottest during the afternoon, while being among the coolest during the early morning hours. While during the early morning some coastal sites were the hottest, the warm air plume slowly moved to the densely urbanized center of the city until 14:00-15:00, moving then further west, to the Elefsis industrial area in the afternoon. Results from the UrbClim model agree fairly well with the observations. Satellite-derived land surface temperature (LST) data from AATSR, ASTER, AVHRR and MODIS, for pixels corresponding to ground stations measuring Tair, showed that LST can be up to 5K lower than the respective Tair during nighttime, while it can be up to 15K higher during the rest of the day. Generally, LST during late afternoon as acquired from AATSR is very near to Tair for all stations and all days, i.e., the AATSR LST afternoon retrieval can be used as a very good approximation of Tair. The hourly evolution of the spatial Tair distribution was almost the same during days with NE Etesian flow as in days with sea breeze circulation, indicating that the mean wind flow was not the main factor controlling the diurnal UHI evolution, although it influenced the temperatures attained. No unambiguous observation of the urban moisture excess (UME) phenomenon could be made.

  7. Geospatial Strategy for Adverse Impact of Urban Heat Island in upper atmospheres of the earth Mountain Areas using LANDSAT ETM+ Sensors

    Science.gov (United States)

    Kumar, Amit; Vandana, Vandana

    2016-07-01

    We are living in the age of the rapidly growing population and changing environmental conditions with advanced technical capacity. This has been resulting in widespread land cover change. Among several human-induced environmental and urban thermal problems are reported to be negatively affecting urban residents in many ways. Urban Heat Islands exist in many large cities especially metropolitan cities and can significantly affect the permafrost layer in mountain areas. The adverse effect of urban heat island has become the subject of numerous studies in recent decades and is reflected in many major mountain cities around the world. The built-up structures in urbanized areas considerably alter land cover thereby affecting thermal energy flow which leads to the development of elevated surface and air temperature. The phenomenon Urban Heat Island implies 'island' of high temperature in cities, surrounded by relatively lower temperature in rural areas. The Urban Heat Island for the temporal period is estimated using geospatial techniques which are then utilized for the impact assessment of the climate of the surrounding regions and how it reduce the sustainability of the natural resources like air, vegetation. The knowledge of surface temperature is important for the study of urban climate and human health. The rapid growth of industries in peri-urban areas results in excessive warming and variations in weather conditions. It leads to soil degradation in frozen areas due to high temperature which leads to melting of snow in mountain areas Remotely sensed data of thermal infrared band in the region of 10.4-12.5 µm of EMR spectrum, available from LANDSAT- ETM+ is proved to be very helpful to identify urban heat islands. Thermal infrared data acquired during the daytime and night time can be used to monitor the heat island associated with urban areas as well as atmospheric pollution. The present paper describes the methodology and resolution dynamic urban heat island

  8. Optimizing a mixed water heating system (solar and electric for rural areas - doi: 10.4025/actascitechnol.v35i1.11998

    Directory of Open Access Journals (Sweden)

    Maurício Medeiros

    2013-01-01

    Full Text Available The increasing consumption of electric energy used for heating water especially in peak periods, requires the use of alternative energy sources that meet the same needs being less costly. The use of solar energy for heating water allows reducing the demand and consumption of electric energy by a conventional electric shower. This study aimed at developing a software to simulate, design, and optimize a mixed water heating system (solar and electric, by using the software MATLAB. This software designed independently the area of a solar collector, the volume of the boiler, and the power of the auxiliary electrical resistance, in order to meet the needs of hot water and ensure the least annual cost. The optimized system when compared with the use of a conventional electric shower presented a time for return of the invested capital of around seven months.  

  9. Modelling of a solar stove: small scale concentrating system with heat storage: potential for cooking in rural areas, Zimbabwe

    Energy Technology Data Exchange (ETDEWEB)

    Chikukwa, Actor

    2007-10-15

    programme is to simulate the heat transfer mechanisms taking place within the fibrous receiver during operation. The predicted results are then presented and discussed in detail. The transportation of the hot air from the receiver, the ceding of its sensible energy to rockbed thermal storage and insulation are deliberated in chapter 5. Another major computer programme that models these processes is written, in which case, results for different inputs are discussed and compared. The need to devise an airpump capable of adjusting the mass flow rate in order to sustain a constant inlet air temperature to the storage is highlighted. Chapter 6 describes the design of the hotplates and their incorporation to the storage unit. The premise on which the third major computer model in this work is discussed in detail. This simulation programme attempts to model a cooking process, in which case, the thermal storage is simultaneously discharged. The results are presented and an overview of the merits of a successful system are briefly discussed. Finally, major conclusions, recommendations and areas for further study are given(Author). refs., figs., tabs

  10. A comparison of urban heat islands mapped using skin temperature, air temperature, and apparent temperature (Humidex), for the greater Vancouver area.

    Science.gov (United States)

    Ho, Hung Chak; Knudby, Anders; Xu, Yongming; Hodul, Matus; Aminipouri, Mehdi

    2016-02-15

    Apparent temperature is more closely related to mortality during extreme heat events than other temperature variables, yet spatial epidemiology studies typically use skin temperature (also known as land surface temperature) to quantify heat exposure because it is relatively easy to map from satellite data. An empirical approach to map apparent temperature at the neighborhood scale, which relies on publicly available weather station observations and spatial data layers combined in a random forest regression model, was demonstrated for greater Vancouver, Canada. Model errors were acceptable (cross-validated RMSE=2.04 °C) and the resulting map of apparent temperature, calibrated for a typical hot summer day, corresponded well with past temperature research in the area. A comparison with field measurements as well as similar maps of skin temperature and air temperature revealed that skin temperature was poorly correlated with both air temperature (R(2)=0.38) and apparent temperature (R(2)=0.39). While the latter two were more similar (R(2)=0.87), apparent temperature was predicted to exceed air temperature by more than 5 °C in several urban areas as well as around the confluence of the Pitt and Fraser rivers. We conclude that skin temperature is not a suitable proxy for human heat exposure, and that spatial epidemiology studies could benefit from mapping apparent temperature, using an approach similar to the one reported here, to better quantify differences in heat exposure that exist across an urban landscape. PMID:26706765

  11. Heat stress in urban areas. Indoor and outdoor temperatures in different urban structure types and subjectively reported well-being during a heat wave in the city of Leipzig

    Energy Technology Data Exchange (ETDEWEB)

    Franck, Ulrich; Roeder, Stefan; Schlink, Uwe [Helmholtz Centre for Environmental Research - UFZ, Leipzig (Germany). Core Facility Studies; Krueger, Michael [Leipzig Univ. (Germany). Inst. of Geography; Schwarz, Nina [Helmholtz Centre for Environmental Research - UFZ, Leipzig (Germany). Dept. of Computational Landscape Ecology; Grossmann, Katrin [Helmholtz Centre for Environmental Research - UFZ, Leipzig (Germany). Dept. of Urban and Environmental Sociology

    2013-04-15

    Climate projections for Leipzig suggest elevated minimum and maximum temperatures as well as more frequent days with high temperatures. Hence, climate change is threatening human well-being and health. People spend the majority of their time indoors. Therefore, indoor temperatures (especially during the night) are of special importance with respect to well-being and health. Indoor air temperature depends on outdoor air temperatures, but is for example modified by type of urban structure, housing area, and may be also influenced by differences in the behavior of the inhabitants. Especially in cities, outdoor air temperatures depend on urban structure e.g. housing density, building arrangement, unpaved areas, types of urban structures, urban green, and other factors. Hence, the questions arise how types of urban structures are related to inner-urban temperature differences and how outdoor air temperatures influence indoor temperatures in dependence on urban housing conditions. This work is a part of a pilot study conducted during the summer 2010 which gathered data from remote sensing, mobile measurements, stationary measurements of air temperatures and relative humidity in areas with different housing structures, and of indoor as well as outdoor temperatures in occupied apartments. Household-survey data reported the subjective perception of heat stress. The study resulted in rather complex relationships between type of housing areas, indoor and outdoor temperatures, morning and evening temperatures, indoor and outdoor temperatures as well as subjective heat perception. Green spaces and types of residential areas are related to air temperatures. More green resulted in lower temperatures. Temperatures have a tendency to increase with increasing story number and are significantly higher in the top floor. An indoor heat island effect corresponding to the outdoor effect could be shown for the homes: Distance to city center is a predicting variable for both outdoor and

  12. Heat stress in urban areas: Indoor and outdoor temperatures in different urban structure types and subjectively reported well-being during a heat wave in the city of Leipzig

    Directory of Open Access Journals (Sweden)

    Ulrich Franck

    2013-04-01

    Full Text Available Climate projections for Leipzig suggest elevated minimum and maximum temperatures as well as more frequent days with high temperatures. Hence, climate change is threatening human well-being and health. People spend the majority of their time indoors. Therefore, indoor temperatures (especially during the night are of special importance with respect to well-being and health. Indoor air temperature depends on outdoor air temperatures, but is for example modified by type of urban structure, housing area, and may be also influenced by differences in the behavior of the inhabitants. Especially in cities, outdoor air temperatures depend on urban structure e.g. housing density, building arrangement, unpaved areas, types of urban structures, urban green, and other factors. Hence, the questions arise how types of urban structures are related to inner-urban temperature differences and how outdoor air temperatures influence indoor temperatures in dependence on urban housing conditions. This work is a part of a pilot study conducted during the summer 2010 which gathered data from remote sensing, mobile measurements, stationary measurements of air temperatures and relative humidity in areas with different housing structures, and of indoor as well as outdoor temperatures in occupied apartments. Household-survey data reported the subjective perception of heat stress. The study resulted in rather complex relationships between type of housing areas, indoor and outdoor temperatures, morning and evening temperatures, indoor and outdoor temperatures as well as subjective heat perception. Green spaces and types of residential areas are related to air temperatures. More green resulted in lower temperatures. Temperatures have a tendency to increase with increasing story number and are significantly higher in the top floor. An indoor heat island effect corresponding to the outdoor effect could be shown for the homes: Distance to city center is a predicting variable for

  13. Techno-economic analysis of single U-tube and double U-tube heat exchangers in Chongqing area

    Institute of Scientific and Technical Information of China (English)

    王勇; 郭凯生; 田荣; 韩传璞; 赖道新; 徐峰

    2009-01-01

    On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.

  14. Progress on system for applying simultaneous heat and brachytherapy to large-area surface disease (Invited Paper)

    Science.gov (United States)

    Stauffer, Paul R.; Schlorff, Jaime L.; Juang, Titania; Neuman, Daniel G., Jr.; Johnson, Jessi E.; Maccarini, Paolo F.; Pouliot, Jean

    2005-04-01

    Laboratory experiments have shown that thermal enhancement of radiation response increases substantially for higher thermal dose (approaching 100 CEM43) and when hyperthermia and radiation are delivered simultaneously. Unfortunately, equipment capable of delivering uniform doses of heat and radiation simultaneously has not been available to test the clinical potential of this approach. We present recent progress on the clinical implementation of a system that combines the uniform heating capabilities of flexible printed circuit board microwave array applicators with an array of brachytherapy catheters held a fixed distance from the skin for uniform radiation of tissue deep with a scanning high dose rate (HDR) brachytherapy source. The system is based on the Combination Applicator which consists of an array of up to 32 Dual Concentric Conductor (DCC) apertures driven at 915 MHz for heating tissue, coupled with an array of 1 cm spaced catheters for HDR therapy. Efforts to optimize the clinical interface and move from rectangular to more complex shape applicators that accommodate the entire disease in a larger number of patients are described. Improvements to the system for powering and controlling the applicator are also described. Radiation dosimetry and experimental performance results of a prototype 15 x 15 cm dual-purpose applicator demonstrate dose distributions with good homogeneity under large contoured surfaces typical of diffuse chestwall recurrence of breast carcinoma. Investigations of potential interaction between heat and brachytherapy components of a Combination Applicator demonstrate no perceptible perturbation of the heating field from an HDR source or leadwire, no perceptible effect of a scanning HDR source on fiberoptic thermometry, and heat and radiation simultaneously for maximum synergism of modalities, this dual therapy system should expand the number of patients that can benefit from effective thermoradiotherapy treatments.

  15. Does Artificial Ascites Induce the Heat-Sink Phenomenon during Percutaneous Radiofrequency Ablation of the Hepatic Subcapsular Area?: an in vivo Experimental Study Using a Rabbit Model

    OpenAIRE

    Kim, Young-sun; Rhim, Hyunchul; Choi, Dongil; Lim, Hyo K.

    2009-01-01

    Objective To evaluate the effect of the heat-sink phenomenon induced by artificial ascites on the size of the ablation zone during percutaneous radiofrequency (RF) ablation of the hepatic subcapsular area in an in vivo rabbit model. Materials and Methods A total of 21 percutaneous rabbit liver RF ablations were performed with and without artificial ascites (5% dextrose aqueous solution). The rabbits were divided into three groups: a) control group (C, n = 7); b) room temperature ascites group...

  16. The geothermal potential of the Campania volcanic district and new heat exchanger technologies for exploitation of highly urbanised areas.

    Science.gov (United States)

    Carlino, S.; Somma, R.; Troiano, A.; Di Giuseppe, M. G.; Troise, C.; De Natale, G.

    2012-04-01

    The geothermal research in Campania region (Italy), started since the 1930, and continued until the '80 by the SAFEN, ENEL and AGIP companies. Such exploration activity highlighted that most of the volcanic districts of the Campania Region have a very high geothermal gradient and heat flow. In particular, inside the Campi Flegrei caldera and at Ischia island the geothermal gradient measured inside the deep wells reaches temperatures above 100° C between few tens and few hundreds of metres of depth, while the heat flow varies between 120-160 mWm-2 at Agnano and Mofete (Campi Flegrei main drill sites) to more than 500 mWm-2 at Ischia island (south-western sector). A general review of the available literature data (temperature at depth, stratigraphic sections, logs etc.) of the deep wells (down to 3 km b.s.l.) allowed us to quantify the geothermal potential (thermal and electric) of such district. The geothermal potential is about 6 GWy for the Campi Flegrei (Mofete and S. Vito sectors) and 11 GWy for the Ischia island (south-western sector) showing a geothermal reservoir with water and vapour dominant respectively. This results in strong potential interest for economic exploitation of the geothermal resource, both in the range of low-medium enthalpy at few hundreds of meters depth and of high enthalpy at depths of 1-2 km. In this study we try to model the effectiveness of new technologies of boreholes heat exchangers, which would allow to avoid fluid withdrawal, then strongly decreasing the environmental impact. The proposed technology consists of a double-pipe placed in a borehole heat exchange that can work coupled with an ORC. The two pipes, one inside the other, are located in the well in order to transfer the thermal energy to the working fluid during the descent in the external pipe and then go back through the internal pipe properly isolated. We propose a complete design of the borehole heat exchangers. The design activity is performed on a theoretical basis

  17. 梯形积分法计算传热面积%Calculate the Heat Transfer Area by Trapezoidal Integration Method

    Institute of Scientific and Technical Information of China (English)

    王兰娟; 乔合梅

    2012-01-01

    本文介绍了冷、热流体通过间壁式换热器进行无相变热交换时,总传热系数K随温度不呈线性变化条件下传热面积的计算,即梯形求积法,其主要特点是概念清晰,过程简洁,结果准确。作者在教学中采用这些方法,收到了较好的效果。%This article describes the hot and cold fluid through the partitions heat exchanger no phase change heat exchange, the overall heat transfer coefficient K temperature showed a linear change under conditions of heat transfer area calculations, namely the trapezoidal quadrature method, its main features. The concept is clear, the process is simple, accurate results. Of these methods in teaching, and received good results.

  18. Validation of ASTER Surface Temperature Data with In Situ Measurements to Evaluate Heat Islands in Complex Urban Areas

    OpenAIRE

    Bonggeun Song; Kyunghun Park

    2014-01-01

    This study compared Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) surface temperature data with in situ measurements to validate the use of ASTER data for studying heat islands in urban settings with complex spatial characteristics. Eight sites in Changwon, Korea, were selected for analyses. Surface temperature data were extracted from the thermal infrared (TIR) band of ASTER on four dates during the summer and fall of 2012, and corresponding in situ measurements of tempe...

  19. Geothermal Heat Flux Assessment Using Remote Sensing Land Surface Temperature and Simulated Data. Case Studies at the Kenyan Rift and Yellowstone Geothermal Areas

    Science.gov (United States)

    Romaguera, M.; Vaughan, R. G.; Ettema, J.; Izquierdo-Verdiguier, E.; Hecker, C.; van der Meer, F. D.

    2015-12-01

    In this work we propose an innovative approach to assess the geothermal heat flux anomalies in the regions of the Kenyan Rift and the Yellowstone geothermal areas. The method is based on the land surface temperature (LST) differences obtained between remote sensing data and land surface model simulations. The hypothesis is that the model simulations do not account for the subsurface geothermal heat source in the formulation. Remote sensing of surface emitted radiances is able to detect at least the radiative portion of the geothermal signal that is not in the models. Two methods were proposed to assess the geothermal component of LST (LSTgt) based on the aforementioned hypothesis: a physical model and a data mining approach. The LST datasets were taken from the Land Surface Analysis Satellite Application Facilities products over Africa and the Copernicus Programme for North America, at a spatial resolution of 3-5 km. These correspond to Meteosat Second Generation and Geostationary Operational Environmental Satellite system satellites data respectively. The Weather Research and Forecasting model was used to simulate LST based on atmospheric and surface characteristics using the Noah land surface model. The analysis was carried out for a period of two months by using nighttime acquisitions. Higher spatial resolution images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer data were also used on the Kenyan area to produce similar outputs employing existing methods. The comparison of the results from both methods and areas illustrated the potential of the data and methodologies for geothermal applications.

  20. Magnetic fusion energy plasma interactive and high heat flux components. Volume II. Technical assessment of the critical issues and problem areas in high heat flux materials and component development

    International Nuclear Information System (INIS)

    A technical assessment of the critical issues and problem areas for high heat flux materials and components (HHFMC) in magnetic fusion devices shows these problems to be of critical importance for the successful operation of near-term fusion experiments and for the feasibility and attractiveness of long-term fusion reactors. A number of subgroups were formed to assess the critical HHFMC issues along the following major lines: (1) source conditions, (2) systems integration, (3) materials and processes, (4) thermal hydraulics, (5) thermomechanical response, (6) electromagnetic response, (7) instrumentation and control, and (8) test facilities. The details of the technical assessment are presented in eight chapters. The primary technical issues and needs for each area are highlighted

  1. Capture zone delineation methodology based on the maximum concentration: Preventative groundwater well protection areas for heat exchange fluid mixtures

    Science.gov (United States)

    Okkonen, Jarkko; Neupauer, Roseanna M.

    2016-05-01

    Capture zones of water supply wells are most often delineated based on travel times of water or solute to the well, with the assumption that if the travel time is sufficiently large, the concentration of chemical at the well will not exceed the drinking water standards. In many situations, the likely source concentrations or release masses of contamination from the potential sources are unknown; therefore, the exact concentration at the well cannot be determined. In situations in which the source mass can be estimated with some accuracy, the delineation of the capture zone should be based on the maximum chemical concentration that can be expected at the well, rather than on an arbitrary travel time. We present a new capture zone delineation methodology that is based on this maximum chemical concentration. The method delineates capture zones by solving the adjoint of the advection-dispersion-reaction equation and relating the adjoint state and the known release mass to the expected chemical concentration at the well. We demonstrate the use of this method through a case study in which soil heat exchange systems are potential sources of contamination. The heat exchange fluid mixtures contain known fluid volumes and chemical concentrations; thus, in the event of a release, the release mass of the chemical is known. We also demonstrate the use of a concentration basis in quantifying other measures of well vulnerability including exposure time and time to exceed a predefined threshold concentration at the well.

  2. The Influence of green areas and roof albedos on air temperatures during Extreme Heat Events in Berlin, Germany

    Directory of Open Access Journals (Sweden)

    Sebastian Schubert

    2013-04-01

    Full Text Available The mesoscale atmospheric model COSMO-CLM (CCLM with the Double Canyon Effect Parametrization Scheme (DCEP is applied to investigate possible adaption measures to extreme heat events (EHEs for the city of Berlin, Germany. The emphasis is on the effects of a modified urban vegetation cover and roof albedo on near-surface air temperatures. Five EHEs with a duration of 5 days or more are identified for the period 2000 to 2009. A reference simulation is carried out for each EHE with current vegetation cover, roof albedo and urban canopy parameters (UCPs, and is evaluated with temperature observations from weather stations in Berlin and its surroundings. The derivation of the UCPs from an impervious surface map and a 3-D building data set is detailed. Characteristics of the simulated urban heat island for each EHE are analysed in terms of these UCPs. In addition, six sensitivity runs are examined with a modified vegetation cover of each urban grid cell by -25%, 5% and 15%, with a roof albedo increased to 0.40 and 0.65, and with a combination of the largest vegetation cover and roof albedo, respectively. At the weather stations' grid cells, the results show a maximum of the average diurnal change in air temperature during each EHE of 0.82 K and -0.48 K for the -25% and 15% vegetation covers, -0.50 K for the roof albedos of 0.65, and -0.63 K for the combined vegetation and albedo case. The largest effects on the air temperature are detected during midday.

  3. Planning for a Low Carbon Future? Comparing Heat Pumps and Cogeneration as the Energy System Options for a New Residential Area

    Directory of Open Access Journals (Sweden)

    Jukka Heinonen

    2015-08-01

    Full Text Available The purpose of this paper is to compare, from an urban planning perspective, the choice between combined heat and power (CHP and a ground-source heat pump (HP as the energy systems of a new residential area in the light of the uncertainty related to the assessments. There has been a strong push globally for CHP due to its climate mitigation potential compared to separate production, and consequently it is often prioritized in planning without questioning. However, the uncertainties in assessing the emissions from CHP and alternative options in a certain planning situation make it very difficult to give robust decision guidelines. In addition, even the order of magnitude of the climate impact of a certain plan is actually difficult to assess robustly. With a case study of the new residential development of Härmälänranta in Tampere, Finland, we show how strongly the uncertainties related to (1 utilizing average or marginal electricity as the reference; (2 assigning emissions intensities for the production; and (3 allocating the emissions from CHP to heat and electricity affect the results and lead to varying decision guidelines. We also depict how a rather rarely utilized method in assigning the emissions from CHP is the most robust for planning support.

  4. Association of Cancer Incidence and Duration of Residence in Geothermal Heating Area in Iceland: An Extended Follow-Up.

    Directory of Open Access Journals (Sweden)

    Adalbjorg Kristbjornsdottir

    Full Text Available Residents of geothermal areas have higher incidence of non-Hodgkin's lymphoma, breast cancer, prostate cancer, and kidney cancers than others. These populations are exposed to chronic low-level ground gas emissions and various pollutants from geothermal water. The aim was to assess whether habitation in geothermal areas and utilisation of geothermal water is associated with risk of cancer according to duration of residence.The cohort obtained from the census 1981 was followed to the end of 2013. Personal identifier was used in record linkage with nation-wide emigration, death, and cancer registries. The exposed population, defined by community codes, was located on young bedrock and had utilised geothermal water supply systems since 1972. Two reference populations were located by community codes on older bedrock or had not utilised geothermal water supply systems for as long a period as had the exposed population. Adjusted hazard ratio (HR, 95% confidence intervals (CI non-stratified and stratified on cumulative years of residence were estimated in Cox-model.The HR for all cancer was 1.21 (95% CI 1.12-1.30 as compared with the first reference area. The HR for pancreatic cancer was 1.93 (1.22-3.06, breast cancer, 1.48 (1.23-1.80, prostate cancer 1.47 (1.22-1.77, kidney cancer 1.46 (1.03-2.05, lymphoid and haematopoietic tissue 1.54 (1.21-1.97, non-Hodgkin´s lymphoma 2.08 (1.38-3.15 and basal cell carcinoma of the skin 1.62 (1.35-1.94. Positive dose-response relationship was observed between incidence of cancers and duration of residence, and between incidence of cancer and degree of geothermal/volcanic activity in the comparison areas.The higher cancer incidence in geothermal areas than in reference areas is consistent with previous findings. As the dose-response relationships were positive between incidence of cancers and duration of residence, it is now more urgent than before to investigate the chemical and physical content of the geothermal

  5. Zone modeling of radiative heat transfer in industrial furnaces using adjusted Monte-Carlo integral method for direct exchange area calculation

    International Nuclear Information System (INIS)

    This paper proposes the Monte-Carlo Integral method for the direct exchange area calculation in the zone method for the first time. This method is simple and able to handle the complex geometry zone problem and the self-zone radiation problem. The Monte-Carlo Integral method is adjusted to improve the efficiency, so that an acceptable accuracy within a reasonable computation time could be achieved. The zone method with the adjusted Monte-Carlo Integral method is used for the modeling and simulation of the radiation transfer in the industrial furnace. The simulation result is compared with the industrial data and show great accordance. It also shows the high temperature flue gas heats the furnace wall, which reflects the radiant heat to the reactor tubes. The highest temperature of flue gas and the side wall appears in nearly one third of the furnace height from the bottom, which corresponds with the industrial measuring data. The simulation result indicates that the zone method is comprehensive and easy to implement for radiative phenomenon in the furnace. - Highlights: • The Monte Carlo Integral method for evaluating direct exchange areas. • Adjustment from the MCI method to the AMCI method for efficiency. • Examination of the performance of the MCI and AMCI methods. • Development of the 3D zone model with the AMCI method. • The simulation results show good accordance with the industrial data

  6. Quantification of emissions from domestic heating in residential areas of İzmir, Turkey and assessment of the impact on local/regional air-quality.

    Science.gov (United States)

    Sari, Deniz; Bayram, Abdurrahman

    2014-08-01

    Air pollution in cities is a major environmental problem principally in the developing countries. The quantification of emissions is a basic requirement to assess the human influence to the atmosphere. The air quality generally shows decreases with the major contribution residential emissions and meteorology in the winter season in the big cities. Poor meteorological conditions especially inversion events for the efficient mixing of air pollutants occurred during the winter months in İzmir. With this work we quantify the amount of domestic heating emissions for particulate matter (PM10), sulfur dioxides (SO2), nitrogen dioxides (NO2), volatile organic compounds (VOC) and carbon monoxide (CO) together with greenhouse gases which are carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) in İzmir for 2008-2009 winter season. The results showed that the most affected residential areas were central districts in the city center from domestic heating emissions due to meteorological condition and demographic reasons. Air quality modeling is a great tool for assisting policy makers how to decrease emissions and improve air quality. At the second part of the study, calculated emissions were modeled by using CALMET/CALPUFF dispersion modeling system and plotted in the form of air pollution maps by using geographical information system to determine the locations and estimate the effects of the new residential areas that will be established in the future in İzmir.

  7. Quantification of emissions from domestic heating in residential areas of İzmir, Turkey and assessment of the impact on local/regional air-quality

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Deniz, E-mail: deniz.sari@tubitak.gov.tr [TUBITAK Marmara Research Center, Environment and Cleaner Production Institute, 41470 Kocaeli (Turkey); Bayram, Abdurrahman [Department of Environmental Engineering, Faculty of Engineering, Dokuz Eylul University, Kaynaklar Campus, 35160 Buca, Izmir (Turkey)

    2014-08-01

    Air pollution in cities is a major environmental problem principally in the developing countries. The quantification of emissions is a basic requirement to assess the human influence to the atmosphere. The air quality generally shows decreases with the major contribution residential emissions and meteorology in the winter season in the big cities. Poor meteorological conditions especially inversion events for the efficient mixing of air pollutants occurred during the winter months in İzmir. With this work we quantify the amount of domestic heating emissions for particulate matter (PM10), sulfur dioxides (SO{sub 2}), nitrogen dioxides (NO{sub 2}), volatile organic compounds (VOC) and carbon monoxide (CO) together with greenhouse gases which are carbon dioxide (CO{sub 2}), nitrous oxide (N{sub 2}O) and methane (CH{sub 4}) in İzmir for 2008–2009 winter season. The results showed that the most affected residential areas were central districts in the city center from domestic heating emissions due to meteorological condition and demographic reasons. Air quality modeling is a great tool for assisting policy makers how to decrease emissions and improve air quality. At the second part of the study, calculated emissions were modeled by using CALMET/CALPUFF dispersion modeling system and plotted in the form of air pollution maps by using geographical information system to determine the locations and estimate the effects of the new residential areas that will be established in the future in İzmir. - Highlights: • The air pollution in cities especially shows raises with the opening of winter season. • Air pollution has become a problem due to rapid urbanization in İzmir, Turkey. • The air quality shows decreases with the residential emissions in İzmir's winter. • With this work we quantify the amount of domestic heating emissions for pollutants. • The impact of emissions on local air-quality is determined by using dispersion model.

  8. Quantification of emissions from domestic heating in residential areas of İzmir, Turkey and assessment of the impact on local/regional air-quality

    International Nuclear Information System (INIS)

    Air pollution in cities is a major environmental problem principally in the developing countries. The quantification of emissions is a basic requirement to assess the human influence to the atmosphere. The air quality generally shows decreases with the major contribution residential emissions and meteorology in the winter season in the big cities. Poor meteorological conditions especially inversion events for the efficient mixing of air pollutants occurred during the winter months in İzmir. With this work we quantify the amount of domestic heating emissions for particulate matter (PM10), sulfur dioxides (SO2), nitrogen dioxides (NO2), volatile organic compounds (VOC) and carbon monoxide (CO) together with greenhouse gases which are carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) in İzmir for 2008–2009 winter season. The results showed that the most affected residential areas were central districts in the city center from domestic heating emissions due to meteorological condition and demographic reasons. Air quality modeling is a great tool for assisting policy makers how to decrease emissions and improve air quality. At the second part of the study, calculated emissions were modeled by using CALMET/CALPUFF dispersion modeling system and plotted in the form of air pollution maps by using geographical information system to determine the locations and estimate the effects of the new residential areas that will be established in the future in İzmir. - Highlights: • The air pollution in cities especially shows raises with the opening of winter season. • Air pollution has become a problem due to rapid urbanization in İzmir, Turkey. • The air quality shows decreases with the residential emissions in İzmir's winter. • With this work we quantify the amount of domestic heating emissions for pollutants. • The impact of emissions on local air-quality is determined by using dispersion model

  9. Estimation of the soil heat flux/net radiation ratio based on spectral vegetation indexes in high-latitude Arctic areas

    International Nuclear Information System (INIS)

    The vegetation communities in the Arctic environment are very sensitive to even minor climatic variations and therefore the estimation of surface energy fluxes from high-latitude vegetated areas is an important subject to be pursued. This study was carried out in July-August and used micro meteorological data, spectral reflectance signatures, and vegetation biomass to establish the relation between the soil heat flux/net radiation (G / Rn) ratio and spectral vegetation indices (SVIs). Continuous measurements of soil temperature and soil heat flux were used to calculate the surface ground heat flux by use of conventional methods, and the relation to surface temperature was investigated. Twenty-seven locations were established, and six samples per location, including the measurement of the surface temperature and net radiation to establish the G/Rn ratio and simultaneous spectral reflectance signatures and wet biomass estimates, were registered. To obtain regional reliability, the locations were chosen in order to represent the different Arctic vegetation communities in the study area; ranging from dry tundra vegetation communities (fell fields and dry dwarf scrubs) to moist/wet tundra vegetation communities (snowbeds, grasslands and fens). Spectral vegetation indices, including the simple ratio vegetation index (RVI) and the normalized difference vegetation index (NDVI), were calculated. A comparison of SVIs to biomass proved that RVI gave the best linear expression, and NDVI the best exponential expression. A comparison of SVIs and the surface energy flux ratio G / Rn proved that NDVI gave the best linear expression. SPOT HRV images from July 1989 and 1992 were used to map NDVI and G / Rn at a regional scale. (author)

  10. Heat Island Effect and Diurnal Temperature Range in Beijing Area%北京地区热岛效应及日较差特征

    Institute of Scientific and Technical Information of China (English)

    刘伟东; 杨萍; 尤焕苓; 张本志

    2013-01-01

    The K-means clustering method was used to determine quality-controlled hourly surface air temperature data of 123 automatic weather stations in the Beijing area. The sites of these stations were classified into the following four zones, that is urban stations, suburban stations, west and north mountainous area stations, and southwest and northeast mountainous area stations. Monthly and diurnal temperature variations and diurnal temperature range (DTR) of the four zones were analyzed and hourly and monthly urban heat islands were investigated. K-means clustering proved advantageous in classifying temperature zones, which were correlated with the terrain and underlying surfaces of the stations. The DTR of the urban zone was revealed to be smaller than that in suburban and mountainous areas. The west and north mountainous areas exhibited the highest DTR values. All zones exhibited high DTR values in February, May, and October. The urban heat island effect in the Beijing area was stronger in winter and at night. In the daytime, the urban heat island effect appeared to be stronger in summer than that in other seasons. From March to August, the urban heat island effect was the weakest.%  通过对2007~2010年北京地区经质量控制后的123个自动气象站气温数据采用K均值聚类方法分类,得到城区、郊区、西部和北部山区、西南和东北部山区4个温度分区,分析了4个分区气温的年变化、日变化和日较差变化特征,并对北京地区热岛效应的时间变化特征进行了细致分析。结果表明:聚类分析方法可对北京地区温度很好地进行分区,分区结果与站点的地形和下垫面情况较为吻合;不同分区温度日较差在西部和北部山区最大,在西南部和东北部山区次之,郊区再次之,在城区的日较差最小;在一年中,各温度分区以2月、5月与10月日较差较大,其中以5月的日较差为最大;北京地区热岛效应

  11. Green and cool roofs to mitigate urban heat island effects in the Chicago metropolitan area: evaluation with a regional climate model

    Science.gov (United States)

    Sharma, A.; Conry, P.; Fernando, H. J. S.; Hamlet, Alan F.; Hellmann, J. J.; Chen, F.

    2016-06-01

    The effects of urban heat islands (UHIs) have a substantial bearing on the sustainability of cities and environs. This paper examines the efficacy of green and cool roofs as potential UHI mitigation strategies to make cities more resilient against UHI. We have employed the urbanized version of the Weather Research and Forecasting (uWRF) model at high (1 km) resolution with physically-based rooftop parameterization schemes (conventional, green and cool), a first-time application to the Chicago metropolitan area. We simulated a hot summer period (16-18 August 2013) and assessed (i) UHI reductions for different urban landuse with green/cool roofs, (ii) the interaction of lake breeze and UHI, and (iii) diurnal boundary layer dynamics. The performance of uWRF was evaluated using sensible heat flux and air temperature measurements from an urban mini-field campaign. The simulated roof surface energy balance captured the energy distribution with respective rooftop algorithms. Results showed that daytime roof temperature reduced and varied linearly with increasing green roof fractions, from less than 1 °C for the case of 25% green roof to ˜3 °C during peak daytime for 100% green roof. Diurnal transitions from land to lake breeze and vice versa had a substantial impact on the daytime cycle of roof surface UHI, which had a 3-4 hour lag in comparison to 2 m UHI. Green and cool roofs reduced horizontal and vertical wind speeds and affected lower atmosphere dynamics, including reduced vertical mixing, lower boundary layer depth, and weaker convective rolls. The lowered wind speeds and vertical mixing during daytime led to stagnation of air near the surface, potentially causing air quality issues. The selection of green and cool roofs for UHI mitigation should therefore carefully consider the competing feedbacks. The new results for regional land-lake circulations and boundary layer dynamics from this study may be extended to other urbanized areas, particularly to coastal

  12. Technical and economical analysis of concepts for using the heat of biogas plants in rural areas; Technische und betriebswirtschaftliche Analyse von Konzepten zur ganzjaehrigen Nutzung der Abwaerme einer Biogasanlage im dezentralen laendlichen Raum

    Energy Technology Data Exchange (ETDEWEB)

    Kaths, Friederike Annette

    2012-08-15

    Since the implementation of the EEG in Germany the biogas production becomes an independent branch of industry in the agriculture. At this time more than 90 percent of the biogas plants work with co-generation plant for heat and power with a thermal engine efficiencies of more than 50 percent. Because of the location in the rural area heat costumers with a continuous demand of heat over the whole year are rare. This research had a closer look how to use the heat of biogas production efficiently and also generating profit. The aim of the study was to use heat over the whole year, a profitable heat concept without counting the KWK-bonus and an added value on the farm. During the study the following concepts were analyzed: asparagus production using soil heating, drying equipment for different products, the production of fish in aquaculture, the poultry production and the heated production of tomatoes. The results showed different concepts using heat of biogas plants as efficient for farmers. However with only one concept the aims - to use the heat over the whole year, generating a profitable heat concept without counting the KWK-bonus, add an value on the farm - mostly can not be achieved. The combination of different heat concepts is necessary. In this analysis the poultry production in combination with the dryer can be considered as the most efficient concept. Bearing in mind the benefit which can be generated with a heat concept as well as the higher income and the higher technical efficiency of biogas plants operators should implement an individual concept for their heat.

  13. The Effect of Vegetation Coverage and Greenhouse Area on the Performance of an Earth-to-Air Heat Exchanger in Cooling Mode of Greenhouse

    Directory of Open Access Journals (Sweden)

    M Mohammadi Mogharreb

    2013-02-01

    Full Text Available The underground temperature at a depth of about three to four meters is almost constant during the year. As a result in summer the underground is cooler than the ambient temperature. This potential is considered for greenhouse cooling by using an Earth-to-Air Heat Exchanger (EAHE. In this research the effects of two parameters were investigated: a the area of greenhouse in three levels of 9, 18, 27 m2 and b the percent of vegetation coverage inside the greenhouse in three levels of 0%, 50%, 100% on the performance of EAHE. The experimental design was factorial experiment in a randomized complete block design. The parameters of greenhouse’s inside temperature, thermal energy exchange and coefficient of performance (COP were considered in cooling mode. As one of the remarkable results it was observed that the closed loop utilization of the system was infeasible in cooling mode. This was mainly due to the occurrence of vapor distillation inside the underground pipes and hence the blockages of the air flow. Also the effect of area and the percent of vegetation coverage were significant on the performance of EAHE. The highest average temperature difference between the temperature of testimonial greenhouse and the temperature of greenhouse was observed in treatment of 100% vegetation coverage and 9 m2 floor area which was measured as 9.6°C. The least average temperature difference in the treatment without vegetation coverage and 27 m2 floor area was measured as 5.2 °C. Considering thermal energy exchange in cooling greenhouse with open loop, the best treatment determined for EAHE in this research was the one with 9 m2 floor area and 100% of vegetation coverage.

  14. A Case Study of Urbanization Impact on Summer Precipitation in the Greater Beijing Metropolitan Area. Urban Heat Island Versus Aerosol Effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Shi [Nanjing Univ. (China); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qian, Yun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Chun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leung, Lai-Yung R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Yang, Xiuqun [Nanjing Univ. (China)

    2015-10-23

    Convection-resolving ensemble simulations using the WRF-Chem model coupled with a single-layer Urban Canopy Model (UCM) are conducted to investigate the individual and combined impacts of land use and anthropogenic pollutant emissions from urbanization on a heavy rainfall event in the Greater Beijing Metropolitan Area (GBMA) in China. The simulation with the urbanization effect included generally captures the spatial pattern and temporal variation of the rainfall event. An improvement of precipitation is found in the experiment including aerosol effect on both clouds and radiation. The expanded urban land cover and increased aerosols have an opposite effect on precipitation processes, with the latter playing a more dominant role, leading to suppressed convection and rainfall over the upstream (northwest) area, and enhanced convection and more precipitation in the downstream (southeast) region of the GBMA. In addition, the influence of aerosol indirect effect is found to overwhelm that of direct effect on precipitation in this rainfall event. Increased aerosols induce more cloud droplets with smaller size, which favors evaporative cooling and reduce updrafts and suppress convection over the upstream (northwest) region in the early stage of the rainfall event. As the rainfall system propagates southeastward, more latent heat is released due to the freezing of larger number of smaller cloud drops that are lofted above the freezing level, which is responsible for the increased updraft strength and convective invigoration over the downstream (southeast) area.

  15. A case study of urbanization impact on summer precipitation in the Greater Beijing Metropolitan Area: Urban heat island versus aerosol effects

    Science.gov (United States)

    Zhong, Shi; Qian, Yun; Zhao, Chun; Leung, Ruby; Yang, Xiu-Qun

    2015-10-01

    Convection-resolving ensemble simulations using the WRF-Chem model coupled with a single-layer Urban Canopy Model are conducted to investigate the individual and combined impacts of land use and anthropogenic pollutant emissions from urbanization on a heavy rainfall event in the Greater Beijing Metropolitan Area (GBMA) in China. The simulation with the urbanization effect included generally captures the spatial pattern and temporal variation of the rainfall event. An improvement of precipitation is found in the experiment including aerosol effect on both clouds and radiation. The expanded urban land cover and increased aerosols have an opposite effect on precipitation processes, with the latter playing a more dominant role, leading to suppressed convection and rainfall over the upstream (northwest) area, and enhanced convection and more precipitation in the downstream (southeast) region of the GBMA. In addition, the influence of aerosol indirect effect is found to overwhelm that of direct effect on precipitation in this rainfall event. Increased aerosols lead to more cloud droplets with smaller size, which favor evaporative cooling and reduce updrafts and suppress convection over the upstream (northwest) region in the early stage of the rainfall event. As the rainfall system propagates southeastward, more latent heat is released due to the freezing of larger number of smaller cloud drops that are lofted above the freezing level, which is responsible for the increased updraft strength and convective invigoration over the downstream (southeast) area.

  16. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving x-ray crystal optics

    CERN Document Server

    Stoupin, S; Butler, J E; Kolyadin, A V; Katrusha, A

    2016-01-01

    We report fabrication and results of high-resolution X-ray topography characterization of diamond single crystal plates with a large surface area (10$\\times$10 mm$^2$) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics. The plates were fabricated by laser cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature method. The intrinsic crystal quality of a selected 3$\\times$7~mm$^2$ crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. The wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking curve topography. The variation of the rocking curve width and peak position measured with a spatial resolution of 13$\\times$13 $\\mu m^2$ over the selected region were found to be less than one microradian.

  17. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics.

    Science.gov (United States)

    Stoupin, Stanislav; Antipov, Sergey; Butler, James E; Kolyadin, Alexander V; Katrusha, Andrey

    2016-09-01

    Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. The variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

  18. Production of long chain omega-3 fatty acids and carotenoids in tropical areas by a new heat-tolerant microalga Tetraselmis sp. DS3.

    Science.gov (United States)

    Tsai, Hsin-Pei; Chuang, Lu-Te; Chen, Ching-Nen Nathan

    2016-02-01

    Demand for long chain ω-3 fatty acids from non-fish source for vegetarians has increased recently. Marine microalgae are the primary producers of EPA/DHA and promising alternatives for fish oil. Tropical areas have abundant sunlight throughout the year for microalgal cultivation but this practice can be hindered by high temperature. Discovery of heat-tolerant marine microalgae that can synthesize EPA/DHA will solve these problems. A new species of microalga was isolated from a high temperature lagoon and identified as Tetraselmis sp. DS3. These cells could grow at 40 °C, the highest temperature for marine microalgal growth ever reported. Its ω-3 fatty acids and EPA accounted for 33 and 10% of total lipids, respectively, grown in nitrogen-depleted conditions. These cells also accumulated more than 5% β-carotene and 0.48% lutein in biomass. This new microalga can be cultivated for long chain ω-3 fatty acids and lutein production in the tropical areas.

  19. Heat savings in buildings in a 100% renewable heat and power system in Denmark with different shares of district heating

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Balyk, Olexandr

    2014-01-01

    levels of heat savings, which can be implemented by reducing heat transmission losses through building elements and by installing ventilation systems with heat recovery, in different future Danish heat and power system scenarios. Today almost 50% of heat demand in Denmark is covered by district heating...... effective to reduce from approximately 12% to 17% of future heat demand in buildings depending on assumed lifetime and costs of heat saving measures. Individual heating areas have higher penetration of heat savings than district heating areas. When district heating systems are expanded, an overall...... penetration of heat savings slightly decreases along with lower capacity investments and system costs....

  20. Heat pipes in modern heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L.L. [Academy of Science, Minsk (Russian Federation). A.V. Luikov Heat and Mass Transfer Institute

    2005-01-01

    Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 10{sup 3}-10{sup 5} W/m{sup 2} K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included. (author)

  1. Radon as a tracer to characterize the interactions between groundwater and surface water around the ground source heat pump system in riverside area

    Science.gov (United States)

    Kim, Jaeyeon; Lee, Seong-Sun; Lee, Kang-Kun

    2016-04-01

    The interaction characteristics between groundwater and surface water was examined by using Radon-222 at Han River Environmental Research Center (HRERC) in Korea where a geothermal resource using indirect open loop ground source heat pump (GSHP) has been developed. For designing a high efficiency performance of the open loop system in shallow aquifer, the riverside area was selected for great advantage of full capacity of well. From this reason groundwater properties of the study site can be easily influenced by influx of surrounding Han River. Therefore, 12 groundwater wells were used for monitoring radon concentration and groundwater level with fluctuation of river stage from May, 2014 to Apr., 2015. The short term monitoring data showed that the radon concentration was changed in accordance with flow meter data which was reflected well by the river stage fluctuation. The spatial distribution of radon concentration from long term monitoring data was also found to be affected by water level fluctuation by nearby dam activity and seasonal effect such as heavy rainfall and groundwater pumping. The estimated residence time indicates that river flows to the study site change its direction according to the combined effect of river stage and groundwater hydrology. In the linear regression of the values, flow velocities were yielded around 0.04 to 0.25 m/day which were similar to flow meter data. These results reveal that Radon-222 can be used as an appropriate environmental tracer in examining the characteristics of interaction in consideration of fluctuating river flow on operation of GSHP in the riverside area. ACKNOWLEDGEMENT This work was supported by the research project of "Advanced Technology for Groundwater Development and Application in Riversides (Geowater+) in "Water Resources Management Program (code 11 Technology Innovation C05)" of the MOLIT and the KAIA in Korea.

  2. Heating system design for National Hongqi Primary School in Yushu area, Qinghai Province%青海玉树州民族红旗小学供暖系统设计

    Institute of Scientific and Technical Information of China (English)

    张宁; 辜兴军; 革非; 戎向阳; 冯雅

    2013-01-01

    In the light of the engineering characteristics and climate conditions, the project adopts the heating system of solar energy plus low temperature type air-source heat pump. Presents the design of the system and its control requirements. The, system adopts passive heating mode to satisfy the demand for heating during abundant sunshine periods and active heating mode during the other periods. In areas with abundant sunshine, using the solar energy and heat pump heating system reasonably and effectively can save system operation costs and reduce environment pollution caused by burning fossil fuels.%结合工程特点和气候条件,该工程采用了太阳能+低温型空气源热泵供暖系统.介绍了系统设计及其控制要求.在日照丰富的时段,采用被动式供暖方式满足室内供暖需求;在其他时段,则采用主动式供暖方式.在日照丰富的地区,合理有效地利用太阳能和热泵供暖系统,不仅能节省系统运行费用,同时也可减轻燃烧矿物燃料带来的环境污染.

  3. Optimizing a mixed water heating system (solar and electric) for rural areas - doi: 10.4025/actascitechnol.v35i1.11998

    OpenAIRE

    Maurício Medeiros; Carlos Eduardo Camargo Nogueira; Jair Antonio Cruz Siqueira; José Henrique Lawder; Samuel Nelson Melegari de Souza; Guilherme de Paula Moreira Fracaro

    2013-01-01

    The increasing consumption of electric energy used for heating water especially in peak periods, requires the use of alternative energy sources that meet the same needs being less costly. The use of solar energy for heating water allows reducing the demand and consumption of electric energy by a conventional electric shower. This study aimed at developing a software to simulate, design, and optimize a mixed water heating system (solar and electric), by using the software MATLAB. This software...

  4. Does Artificial Ascites Induce the Heat-Sink Phenomenon during Percutaneous Radiofrequency Ablation of the Hepatic Subcapsular Area?: an in vivo Experimental Study Using a Rabbit Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Sun; Rhim, Hyun Chul; Choi, Dong Il; Lim, Hyo K. [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2009-02-15

    To evaluate the effect of the heat-sink phenomenon induced by artificial ascites on the size of the ablation zone during percutaneous radiofrequency (RF) ablation of the hepatic subcapsular area in an in vivo rabbit model. A total of 21 percutaneous rabbit liver RF ablations were performed with and without artificial ascites (5% dextrose aqueous solution). The rabbits were divided into three groups: a) control group (C, n = 7); b) room temperature ascites group (R, n = 7); and c) warmed ascites group (W, n = 7). The tip of a 1 cm, internally cooled electrode was placed on the subcapsular region of the hepatic dome via ultrasound guidance, and ablation was continued for 6 min. Changes in temperature of the ascites were monitored during the ablation. The size of the ablation zones of the excised livers and immediate complications rates were compared statistically between the groups (Mann-Whitney U test, Kruskal-Wallis test, linear-by-linear association, p = 0.05). One rabbit from the 'W' group expired during the procedure. In all groups, the ascites temperatures approached their respective body temperatures as the ablations continued; however, a significant difference in ascites temperature was found between groups 'W' and 'R' throughout the procedures (39.2+- 0.4 .deg. C in group W and 33.4+-4.3 .deg. C in group R at 6 min, p = 0.003). No significant difference was found between the size of the ablation zones (782.4+-237.3 mL in group C, 1,172.0+-468.9 mL in group R, and 1,030.6+-665.1 mL in group W, p = 0.170) for the excised liver specimens. Diaphragmatic injury was identified in three of seven cases (42.9%) upon visual inspection of group 'C' rabbits (p = 0.030). Artificial ascites are not likely to cause a significant heat-sink phenomenon in the percutaneous RF ablation of the hepatic subcapsular region

  5. Equal Area Laws and Latent Heat for d -Dimensional RN-AdS Black Hole

    OpenAIRE

    Li-Chun Zhang; Hui-Hua Zhao; Ren Zhao; Meng-Sen Ma

    2014-01-01

    We study the equal area laws of d -dimensional RN-AdS black hole. We choose two kinds of phase diagrams, P-V and T-S . We employ the equal area laws to find an isobar which is the real two-phase coexistence line. Our calculation is much simpler to derive the critical value of the thermodynamic quantities. According to the thermodynamic quantities, we also study the latent heat of the black hole.

  6. Heat-balance Thermal Protection with Heat Pipes for Hypersonic Vehicle

    OpenAIRE

    Rong Yisheng; Wei Yuechuan; Duan Dongli; Zhan Renjun

    2016-01-01

    Heat-balance thermal protection is non-ablating thermal protection for leading edge of hypersonic vehicle. Heat will be quickly transferred from high aerodynamic heating area to low aerodynamic heating area, where the energy will be released by radiation. The temperature of high aerodynamic heating area could be reduced to protect the designed structure from being burned down. Heat-balance thermal protection is summarized. The research on heat-pipe for heat-balance thermal protection is intro...

  7. Urban heat island

    Science.gov (United States)

    Kim, Hongsuk H.

    1991-01-01

    The phenomenon of urban heat island was investigated by the use of LANDSAT Thematic Mapper data sets collected over the metropolitan area of Washington DC (U.S.). By combining the retrieved spectral albedos and temperatures, urban modification on radiation budgets of five surface categories were analyzed. The surface radiation budget imagery of the area show that urban heating is attributable to a large heat flux from the rapidly heating surfaces of asphalt, bare soil and short grass. In summer, symptoms of diurnal heating begin to appear by mid morning and can be about 10 degrees warmer than nearby woodlands in summer.

  8. Economic and environmental benefits analysis of decentralized heating using biomass gasification gas in rural area%农村生物质气化燃气分散供暖经济和环境效益分析

    Institute of Scientific and Technical Information of China (English)

    周卫红; 陈冠益; 马隆龙; 颜蓓蓓; 夏宗鹏

    2014-01-01

    为了充分利用农业废弃物资源,改善北方农村冬季供暖条件,该文对生物质气化燃气分散式供暖技术进行了经济和环境效益分析,探讨其在农村供暖中的可行性。生物质气化分散式供暖具有节约能源、减少大气污染、温度调节方便等优点。通过借鉴天然气分散式供暖的研究成果和对生物质气分散式供暖进行分析,结果表明采取分段式控温、分房间控温和建筑物节能改造等手段可将供暖费用降到合理水平,基本与城市供暖费用相同。通过该文分析可知生物质气化燃气分散式供暖可以作为农村供暖的一种新模式。%The economic and environmental benefits of decentralized heating technology produced by burning gas through the biomass gasification method were analyzed in this paper. The whole decentralized heating system can be divided into three sections. In the first section, the biomass is converted into the biomass gasification gas (i.e., combustible gas). In the second, pipelines are adopted through which the biomass gasification gas is transported to the user’s home. Indoor heating pipes consist of the third section, which connect the transporting pipelines with a gas-heating stove located at the user’s home. The economic estimation shows that the heating cost is 37.59 yuan per square meter in rural areas during a heating period with this kind of decentralized heating system, which is higher than the heating cost in cities. But the decentralized heating method has many other advantages, such as saving energy, easy charging, easy adjusting of the temperature, reducing gas costs, and simultaneous hot water supply. The decentralized heating cost is charged by gas consumption. Thus, household heat meters should be installed for measuring the gas consumption;and accordingly, the charge calculation can be obtained for heating enterprises. Users can easily adjust the indoor temperature in different periods

  9. 大型矿区分散型矿井供暖方式的探讨与思考%Discussion and Thinking of the Ways of Heat Supplying in Distributed Mines of Large Mining Area

    Institute of Scientific and Technical Information of China (English)

    郭长久

    2012-01-01

    通过对国内供暖和神宁煤业集团宁东矿区部分矿井供暖现状和存在的问题分析,提出了大型矿区分散型矿井太阳能、水源热泵供暖的可行性分析,指出在当前节能减排形势下,推进太阳能、水源热泵供暖是摆脱能源消耗总量和环境容量约束、实现真正意义上节能减排的重要举措。%Based on the analysis of current status and existing problems in domestic heat supplying as well as some mines in Ningdong mining area of Shenhua Ningxia Coal Industry Group, the paper not only puts forward the feasibility analysis of solar energy and water source heat pump heat supplying in distributed mines of large mining area, but also points out that promoting solar energy and water source heat pump heat supplying is an important measure to get rid of the constraints of total energy consumption and environmental capacity and realize real energy saving and emission reduction under current situation.

  10. Applicative analysis of Ground-coupled Heat Pump System in Suqian Area%地埋管地源热泵系统在宿迁地区的应用分析

    Institute of Scientific and Technical Information of China (English)

    贾胜辉; 曹亚丽; 顾小雷

    2012-01-01

    The types and work process of ground-coupled heat pump are introduced. The effect of the soil on the ground-coupled heat pump system is analyzed. The application of ground-coupled heat pump system under the Suqian' s climatologic and geological conditions is analyzed. Following a engineering example in Suqian area listed, the reasons why the ground-coupled heat pump system has not been widely used in this area are analyzed. Finally, the suggestions of ground-coupled heat pump system are put forward.%介绍了地埋管地源热泵的系统类型和工作过程,分析了土壤在地埋管地源热泵系统中的作用.结合宿迁地区的气候和地质条件分析地埋管地源热泵系统的适用性并列举工程实例,分析了地埋管地源热泵未普遍应用的原因,最后提出了促进地埋管地源热泵系统在宿迁地区科学发展的建议.

  11. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

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

    constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... are calculated using an energy system model which includes power plants, heat pumps and district heating consumption profiles. The model is developed with focus on accurate representation of the performance of the units in different locations and operating modes. The model can assist in investment decisions...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  12. Modeling urban heat islands in heterogeneous land surface and its correlation with impervious surface area by using night-time ASTER satellite data in highly urbanizing city, Delhi-India

    Science.gov (United States)

    Mallick, Javed; Rahman, Atiqur; Singh, Chander Kumar

    2013-08-01

    The present study is an assessment and identification of urban heat island (UHI) in the environment of one of the fastest urbanizing city of India, Delhi Metropolis, employing satellite image of ASTER and Landsat 7 ETM+ in the thermal infrared region 3-14 μm. Temporal (2001 and 2005) ASTER datasets were used to analyze the spatial structure of the thermal urban environment subsequently urban heat island (UHI) in relation to the urban surface characteristics and land use/land cover (LULC). The study involves derivation of parameters governing the surface heat fluxes, constructing statistics of ASTER thermal infrared images along with validation through intensive in situ measurements. The average images reveal spatial and temporal variations of land surface temperature (LST) of night-time and distinct microclimatic patterns. Central Business District (CBD) of Delhi, (Connaught Place, a high density built up area), and commercial/industrial areas display heat islands condition with a temperature greater than 4 °C compared to the suburbs. The small increase in surface temperature at city level is mainly attributed to cumulative impact of human activities, changes in LULC pattern and vegetation density. In this study the methodology takes into account spatially-relative surface temperatures and impervious surface fraction value to measure surface UHI intensity between the urban land cover and rural surroundings. Both the spatial and temporal variation in surface temperature associated with impervious surface area (ISA) has been evaluated to assess the effect of urbanization on the local climate.

  13. Energy saving analysis of ground-source heat pump and air-source heat pump in Shanghai area%上海地区地埋管地源热泵和空气源热泵的节能性分析

    Institute of Scientific and Technical Information of China (English)

    张静波; 吴建兵; 寿炜炜

    2011-01-01

    从热力学角度对地埋管地源热泵和空气源热泵的节能性进行对比分析,提出了在上海地区地埋管地源热泵相对于空气源热泵节能的设计条件:地埋管换热器出水温度夏季低于30℃,冬季高于10℃.%Compares the energy saving performance of ground-source heat pump and air-source heat pump from the aspect of thermodynamics. Brings forward some suggestions for the application of groundsource heat pump in Shanghai area that the temperature of water from the ground heat exchanger should be less than 30 ℃ in summer and higher than 10 ℃ in winter.

  14. Field-analysis of condensing gas and oil-fired heating installations in the refurbishment area (FAGO); Feldanalyse von kondensierenden Gas- und Oelfeuerungsanlagen im Sanierungsbereich (FAGO)

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M. [Dr. Eicher und Pauli AG, Liestal (Switzerland)

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the performance of twelve condensing heating systems fired by natural gas or heating-oil in real-life situations. The objective of the project - to examine the overall performance and the efficiency of the systems - is discussed. Figures are presented on the measurements made with respect to efficiency of the units. Values are presented for both the lower heating value of the fuels and for the proportion of heating energy obtained from the condensation of water in the flue gases. The over-dimensioning of the systems is commented on. The electricity consumption of the units is also looked at.

  15. Spatial Heat Planning and Heat Demand Reductions in Buildings

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Møller, Bernd; Lund, Henrik

    2013-01-01

    systems. The goal of the thesis is to examine the following questions: 1) Is renewable energy production from buildings useful in district heating areas? 2) What benefits are related to heat savings in buildings within district heating are-as? 3) How do geographic differences in heat consumption...... and supply in-fluence the expansion possibilities of district heating? These questions are examined by establishing different models that focus on both temporal and spatial differences. The primary focus of the first part of the thesis is on the use of solar heating from buildings in general types...... of district heating are-as. This is followed in the second part by a case study which examines heat savings in buildings. The primary focus of the third part of the thesis is on the geographic aspects of district heating and develops geographic models for district heating expansion potentials and uses them...

  16. Heat Exchanger Area Design of Plastic Spiral Pipe of Surface Water Source Heat Pump%地表水源热泵塑料螺旋管换热器面积设计

    Institute of Scientific and Technical Information of China (English)

    押淑芳; 倪龙; 马最良

    2011-01-01

    The existing design material of heat exchanger for surface water source heat pump (SWSHP) is not detail enough,and is disagreement with the characteristics of surface water in China. The application of the material may result in large error. In this paper,through numerical calculations based on simplified mathematic model for the design of plastic spiral pipe heat exchanger, the factors that would significantly influence the heat exchange capacity were found out,including the inlet and outlet temperature difference of heat exchanger and the velocity of surface water. While other factors had little influence, such as type and velocity of heat exchange medium, surface water temperature,etc.. Based on the discussion, the basic heating/cooling design nomograms, the amendment formula for temperature difference of heat exchanger and the amendment table for surface water velocity were presented. Therefore, the applicability of the basic design nomograms was greatly expanded with their convenient performance maintained. The conclusions of this paper would provide useful references for SWSHP design in China.%现有地表水源热泵换热器设计资料粗糙且不完全符合我国地表水的特点,应用误差较大.本文通过塑料螺旋管换热器设计计算简化数学模型的大量数值计算,可知在工程设计值范围内,影响其换热能力的显著因素是换热器进出口温差和地表水体流速,而换热介质种类、换热介质流速和地表水体温度等因素对换热器换热能力的影响不大.在此基础上,给出了供热、供冷工况的基本线算图和换热器进出口温差的修正系数公式、地表水体流速修正系数表.在保持基本线算图简便特性的同时,大大扩展了线算图的使用范围.本文结论可为我国地表水源热泵设计提供参考.

  17. Flow regimes and heat transfer modes identification in ANGRA 2 core, during small break in the primary loop with area of 100 cm2, simulated with RELAP5 code

    International Nuclear Information System (INIS)

    Identifying the flow regimes and the heat transfer modes is important for the analysis of accidents such as the Loss-of-Coolant Accident (LOCA). The aim of this paper is to identify the flow regimes, the heat transfer modes, and the correlations used in the RELAP5/MOD3.2.gama code in ANGRA 2 during the Small-Break Loss-of-Coolant Accident (SBLOCA) with a 100cm2-rupture area in the cold leg of primary loop. The Chapter 15 of the Final Safety Analysis Report of ANGRA 2 (FSAR - A2) reports this specific kind of accident. The results from this work demonstrated the several flow regimes and heat transfer modes that can be present in the core of ANGRA 2 during the postulated accident. (author)

  18. Flow regimes and heat transfer modes identification in ANGRA 2 core, during small break in the primary loop with area of 100 cm{sup 2}, simulated with RELAP5 code

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Eduardo M.; Sabundjian, Gaiane, E-mail: gdgian@ipen.br, E-mail: borges.em@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Identifying the flow regimes and the heat transfer modes is important for the analysis of accidents such as the Loss-of-Coolant Accident (LOCA). The aim of this paper is to identify the flow regimes, the heat transfer modes, and the correlations used in the RELAP5/MOD3.2.gama code in ANGRA 2 during the Small-Break Loss-of-Coolant Accident (SBLOCA) with a 100cm{sup 2}-rupture area in the cold leg of primary loop. The Chapter 15 of the Final Safety Analysis Report of ANGRA 2 (FSAR - A2) reports this specific kind of accident. The results from this work demonstrated the several flow regimes and heat transfer modes that can be present in the core of ANGRA 2 during the postulated accident. (author)

  19. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

  20. Application of Enhanced Vapor Injection Air Source Heat Pump in Northern Cold Area%喷气增焓空气源热泵在北方寒冷地区的应用

    Institute of Scientific and Technical Information of China (English)

    刘畅; 刘强; 秦岩

    2015-01-01

    Based on the policies of reducing air pollution, the enhanced vapor injection (EVI) air source heat pump has been proved to be a good solution. It can be extensively applied in the northern cold area due to its high heat capacity, high heat efficiency and extensive application area. Some typical examples were analyzed to point out the application advantages of the enhanced vapor injection air source heat pump in northern China.%基于当前国内改善空气污染的政策,喷气增焓低环境温度空气源热泵是一个很好的解决方案。由于它具有高制热量、高制热能效、大应用范围的特点,适于在北方寒冷区域推广应用。通过典型应用实例,指出喷气增焓低环境温度空气源热泵在北方区域的应用优势。

  1. Convective heat transfer

    CERN Document Server

    Kakac, Sadik; Pramuanjaroenkij, Anchasa

    2014-01-01

    Intended for readers who have taken a basic heat transfer course and have a basic knowledge of thermodynamics, heat transfer, fluid mechanics, and differential equations, Convective Heat Transfer, Third Edition provides an overview of phenomenological convective heat transfer. This book combines applications of engineering with the basic concepts of convection. It offers a clear and balanced presentation of essential topics using both traditional and numerical methods. The text addresses emerging science and technology matters, and highlights biomedical applications and energy technologies. What’s New in the Third Edition: Includes updated chapters and two new chapters on heat transfer in microchannels and heat transfer with nanofluids Expands problem sets and introduces new correlations and solved examples Provides more coverage of numerical/computer methods The third edition details the new research areas of heat transfer in microchannels and the enhancement of convective heat transfer with nanofluids....

  2. 重庆市主城区热岛效应与植被覆盖关系研究%Relationship between urban heat island effect and vegetation cover in core area of Chongqing City

    Institute of Scientific and Technical Information of China (English)

    杨春华; 雷波; 张晟

    2013-01-01

    为了研究重庆市主城区热岛效应与植被覆盖的关系,利用重庆市主城区2008年TM遥感数据,提取了NDVI(植被归一化)指数,并结合野外实地调查,获取了地表植被覆盖度数据,利用GIS空间分析技术及数理统计方法进行了分析。结果表明,重庆市主城区热岛效应明显,在空间上呈大片、连续分布状态;热岛效应与植被覆盖度呈负相关关系,即随着植被覆盖度的提高而降低,在植被覆盖度高于50%后热岛效应消失。城市绿地面积越大,内外温差也越大,从而形成热岛中的“冷岛”,城市绿地对热岛效应具有重要的减缓作用。%In order to study the relationship between urban heat island effect and vegetation cover in the core area of Chongqing City, the NDVI (Normalized Difference Vegetation Index) is extracted from TM images of the core area of the city in 2008, and the land surface’s vegetation cover data are obtained by field investigation. The relationship between vegetation cover and urban heat island effect was analyzed on the basis of GIS data and corresponding mathematical statistics. The analysis results show that the urban heat island effect in the city core area is very obvious, which extensively appears in a large and connected areas; the urban heat island effect is negatively interrelated with vegetation cover, it reduces with the increase of vegetation cover rate and disappears if the vegetation cover rate is greater than 50%. The bigger area of urban green space is, the bigger temperature differ-ence exists, thereby forming a"cool island" in the heat island. Therefore, the urban green space has an important role in mitiga-ting the urban heat island effect.

  3. HEAT EXCHANGERS IN SEWAGE PIPES

    OpenAIRE

    Podobeková, Veronika; Peráčková, Jana

    2014-01-01

    The article discusses utilization of heat from waste water in sewage. During the year, temperature of water in sewage ranges between 10 °C and 20 °C and the heat from sewage could be used for heating, cooling and hot water preparation in building. The heat is extracted through a transfer surface area of the heat exchanger into the heat pump, which is able to utilize the low–potential energy. Different design and types of the heat exchangers in sewage are dealt with: heat exchangers embedded i...

  4. VII international district heating conference

    International Nuclear Information System (INIS)

    The proceedings of the 7th International District Heating Conference contain the full texts of the 89 presented papers of which 11 fall under the INIS Subject Scope. The conference met in seven sessions and dealt with the following problem areas: design and optimization of systems of district heating, integration of the power system and the district heating systems, cooperation of nuclear and fossil burning sources in district heating systems, the use of specific nuclear power plants for heating purposes, questions of the control of systems of district heating, the development of components of heating networks, the reliability and design of heat supply pipes. (Z.M.)

  5. Research on the effect of heat island in urban area in Shaoyang city%邵阳市城市热岛效应研究

    Institute of Scientific and Technical Information of China (English)

    欧阳海燕

    2015-01-01

    By measuring the temperature of the downtown and suburb in Shaoyang city in 57 feature points and using Arcgis,SPSS software to an-alyze the temperature data,it’s found that the effect of heat island exists in Shaoyang city. And we made the further layout drawing and heat is-land intensity map about the urban heat island effect on Shaoyang city. On the basis of these data,we analyzed the characteristics of spatial and temporal distribution in the heat island and the local climate of Shaoyang city,to explore the formation mechanism of heat island and its influence on Shaoyang city,and put forward feasible countermeasures and suggestions of relieving Shaoyang city’s heat island effect.%通过对邵阳市区城、郊57个特征点气温的测量,运用Arcgis,SPSS等专业软件对气温数据进行了分析,发现邵阳市热岛效应的存在,并进一步作出邵阳市城市热岛效果分布图、热岛强度图,据此分析了邵阳市热岛的时空分布特点和局部小气候特征,探究了热岛的形成机制及其对邵阳市所产生的影响,提出了切实可行的缓解邵阳市城市热岛效应的对策与建议。

  6. Design of Solar Energy Heat Supply and Auxiliary for Soil Source Heat Pump of Hohhot Area%关于建筑节能土壤源热泵太阳能补热设计研究

    Institute of Scientific and Technical Information of China (English)

    刘园园; 唐汝宁; 徐帅

    2014-01-01

    太阳能集热系统结合地源热泵系统是目前先进的可再生能源利用技术。以内蒙古教育厅办公楼土壤源热泵系统为工程实例,通过测量搜集土壤源热泵的实时运行数据、地埋管侧土壤温度变化数据以及热泵机组各项能耗数据,并对数据进行相应的统计计算和分析,得出了教育厅土壤源热泵全年由于北方地区夏季、冬季负荷不均造成的地埋管侧土壤热量的损失量为2098.49 GJ,不平衡比为2:5。详细阐述了该工程土壤源热泵太阳能补热系统的设计过程,并通过经济效益分析验证了其具有良好的节能减排效益,为今后可再生能源利用的研究提供了一定的工程经验、数据和方法。%Currently, solar-thermal system combining the source heat pump system is the most ad-vanced renewable energy utilization technology. The ground-source heat pump system for the office build-ing of Inner Mongolia Education Department is researched. By measuring and collecting the real-time data of soil source heat pump, soil temperature variation of buried pipe side, and the energy consumption of heat pump units, with the corresponding statistical calculations and analysis on the data, the paper elaborated that the soil heat loss of buried pipe side is 2 098.49 GJ caused by the uneven load in northern region be-tween winter and summer, and the unbalance ratio is 2:5. The design process of the ground source heat pump assisted with solar thermal system for local education department is described in detail. The system is proved of good energy conservation efficiency through economic benefit analysis, providing engineering ex-perience, data and methods for researching the renewable energy in future.

  7. Telephone survey concerning ownership and acquisition of a wood burning heating system in the Montreal area; Enquete telephonique sur la possession et l'acquisition d'un systeme de chauffage au bois dans la region de Montreal

    Energy Technology Data Exchange (ETDEWEB)

    Labreche, F.; Bonvalot, Y.; Boivin, M.-C. [Direction de la sante publique de Montreal-Centre, PQ (Canada)

    2000-07-01

    In November 1999, the Direction de la sante publique de Montreal-Centre conducted a telephone survey as part of a larger project aimed at describing the problems caused by wood burning stoves in urban areas. The goal of the survey was to determine a spatial representation of wood burning stoves and fireplaces on the island of Montreal and develop a map displaying the density of wood burning systems and highlight the various characteristics, namely: number, type of device (certified or not, slow burning, etc.) type of combustible used (natural or artificial logs, granule, etc.), quantity of wood burned, preferred use (ambience, main heating system, etc.). The survey covered the entire population of the Montreal community. A total of 7971 families were interviewed and 995 respondents indicated that wood had been burned inside their house. This result led the authors to estimate that 96,900 families used wood burning heating systems on the island, representing approximately 10 per cent of all wood burning families at the provincial level on a area representing less than 0.04 per cent of the Quebec territory. Of the wood burning appliances used, 79.3 per cent are fireplaces, 19.3 per cent are stoves and 1.4 per cent heating systems. Some areas show a user density that is higher than elsewhere, namely in Pierrefonds, Dollard-des-Ormeaux, LaSalle, Ahuntsic, Pointe-aux-Trembles and Riviere-des-Prairies. This survey tied in with the PanCanadian survey conducted in 1998 concerning wood burning heating systems and should allow the teams to refine their calculations with regard to emissions of pollutants.

  8. Spatial-Temporal Changes of Surface Heat Island in the Central Area of Chongqing over the Past 20 Years%近20年来重庆市主城区地表热岛的时空变化

    Institute of Scientific and Technical Information of China (English)

    韩贵锋; 颜文涛; 赵珂; 叶林

    2012-01-01

    To reveal the spatial-temporal changes of the urban heat island in rapidly urbanizing areas, the spatial-temporal changes of surface heat island and relative intensity of surface heat island of Chongqing were analyzed by the CIS spatial analysis functions. The land surface temperatures (LST) in the central area of Chongqing in 1988, 1993, 2001, 2007 and 2009 were retrieved using Landsat TM/ETM + thermal data. The results showed that; 1) over the past 20 years, the spatial pattern of surface urban heat island experienced as evolution from clustered pattern to less clustered pattern, and then again to clustered pattern; 2) the maximum relative heal island intensity increased initially and then decreased; 3) the relative heat island intensity decreased significantly in the old city zone, but increased significantly in the new city groups outside; the relative heat island intensities in the riverside zones near the Yangtze and Jialing Rivers increased significantly aa a result of strong construction activities; 4) the reduced magnitude of the relative heat island intensity in the old city zone was almost equal to the increased magnitude of relative heat island intensity in the new groups outside, and the relative heat island intensity showed a gentle trend in most parts of the study area. The relative heat island intensity changed consistently with the rapid expansion of the city spatially and temporally, and clearly followed the clustered urban structure.%为了揭示快速城市化地区热岛的时空变化特点,以重庆市主城区为例,利用1988-2009年共5个时期的TM/ETM+影像反演地表温度,分析了地表热岛和相对热岛强度的空间格局及其变化趋势.结果表明:近20年来地表热岛的空间格局经历了集聚→较集聚→集聚的演变过程,热岛逐渐由重庆市老城区向外围城市组团转移;最大的相对热岛强度总体呈先增大后减小的变化趋势;老城区的相对热岛强度明显减弱,外围新

  9. Champagne Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    2004-01-01

    The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

  10. The Use of CASES-97 Observations to Assess and Parameterize the Impact of Land-Surface Heterogeneity on Area-Average Surface Heat Fluxes for Large-Scale Coupled Atmosphere-Hydrology Models

    Science.gov (United States)

    Chen, Fei; Yates, David; LeMone, Margaret

    2001-01-01

    To understand the effects of land-surface heterogeneity and the interactions between the land-surface and the planetary boundary layer at different scales, we develop a multiscale data set. This data set, based on the Cooperative Atmosphere-Surface Exchange Study (CASES97) observations, includes atmospheric, surface, and sub-surface observations obtained from a dense observation network covering a large region on the order of 100 km. We use this data set to drive three land-surface models (LSMs) to generate multi-scale (with three resolutions of 1, 5, and 10 kilometers) gridded surface heat flux maps for the CASES area. Upon validating these flux maps with measurements from surface station and aircraft, we utilize them to investigate several approaches for estimating the area-integrated surface heat flux for the CASES97 domain of 71x74 square kilometers, which is crucial for land surface model development/validation and area water and energy budget studies. This research is aimed at understanding the relative contribution of random turbulence versus organized mesoscale circulations to the area-integrated surface flux at the scale of 100 kilometers, and identifying the most important effective parameters for characterizing the subgrid-scale variability for large-scale atmosphere-hydrology models.

  11. Outdoor air supply measure for heated rooms of thermal power plant in severe cold area%严寒地区火力发电厂供暖房间冬季进风措施的探讨

    Institute of Scientific and Technical Information of China (English)

    潘家鹏; 张成义; 朱启振; 孙德锋; 刘金栋

    2011-01-01

    对于严寒地区火力发电厂需要通风和供暖的辅助生产房间,进风形式和保温措施等会直接影响供暖效果.根据实际工程情况,对几种自然进风口进行了比较分析,给出了结论和建议.%For the auxiliary rooms of thermal power plant in severe cold area needing heating and ventilating, the air supply types and thermal insulation measures have direct impacts on the heating effect. Considering the actual situation of some projects, compares and analyses several types of outdoor air supply openings, and gives some conclusions and suggestions.

  12. Heat Stress

    Science.gov (United States)

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

  13. Hybrid Heat Pipes for High Heat Flux Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The thermal transport requirements for future spacecraft missions continue to increase, approaching several kilowatts. At the same time the heat acquisition areas...

  14. 北方地区岩土导热系数及换热量的测试研究%Study on rock-soil thermal conductivity coefficient and heat transfer capacity in north area of China

    Institute of Scientific and Technical Information of China (English)

    李慧星; 李国柱; 陈其针

    2012-01-01

    岩土导热系数是地源热泵地埋管换热器的重要设计参数;测井单位深度换热量是地埋管换热器系统的设计依据.掌握工程区域岩土的热物性及换热性能,是保证地源热泵系统高效、稳定运行的关键.文章建立了现场测试岩土导热系数及换热量的方法,并结合沈阳浑南高新技术产业开发区某地源热泵工程,测试分析了岩土导热系数和测井单位深度换热量.结果表明,该区域的岩土具有较好的导热能力,适合采用地埋管地源热泵系统;在特殊地理条件下设计地源热泵系统方案前,应对拟建区域的地质条件进行全面勘探,以优选工程区域,为岩土热响应测试结果的可靠性提供保障.%The rock-soil thermal conductivity coefficient is an important design parameter for borehole heat exchanger of ground source heat pump (GSHP) system, and the heat exchange of unit borehole depth could provide a reference for the design of GSHP. The grasp of rock-soil thermal properties and heat transfer capacity are the prerequisite for stable and efficient operation of the GSHP system.An in-situ measurement method of the rock -soil thermal conductivity and heat transfer capacity was constructed combined with a GSHP actual project in Shenyang hunnan high-tech development zone , and then the rock-soil thermal conductivity and heat exchange of unit borehole depth were analyzed. The results show that the area has a better heat capacity and suitable for GSHP system. Moreover,geological condition of the region plan to build should be explored comprehensively before the design of GSHP system, which could make the preference of project zone and provide the guarantees for test reliability.

  15. Effect of welding thermal cycles on the structure and properties of simulated heat-affected zone areas in X10CrMoVNb9-1 (T91) steel at a state after 100,000 h of operation

    International Nuclear Information System (INIS)

    The article presents results of structural tests (light, scanning electron and scanning transmission electron microscopy) of X10CrMoVNb9-1 (T91) creep-resisting steel after approximately 100,000 h of operation. It was ascertained that the parent metal of T91 steel is characterized by the microstructure of tempered martensite with M23C6 carbide precipitates and few dispersive precipitates of MX-type niobium and vanadium carbonitrides. The most inconvenient change in T91 steel precipitate morphology due to long-term operation is the appearance of the Laves Fe2Mo phase which along with M23C6 carbide particles forms elongated blocks and conglomerates on grain boundaries. The article also presents results of tests related to the effect of simulated welding thermal cycles on selected properties of X10CrMoVNb9-1 (T91) grade steel at a state after approximately 100,000 h of operation. The tests involved the determination of the chemical composition of the steel tested as well as impact tests, hardness measurements and microscopic metallographic examination (based on light microscopy) of simulated heat-affected zone (HAZ) areas for a cooling time (t8/5) restricted within a range between 3 s and 120 s, with and without heat treatment. The tests revealed that, among other results, hardness values of simulated HAZ areas in X10CrMoVNb9-1 (T91) steel do not guarantee cold crack safety of the steel at the state without additional heat treatment. It was also observed that simulated welding thermal cycles of cooling times t8/5=3, 12, 60 and 120 s do not significantly affect the toughness and hardness of simulated HAZ areas of the steel tested

  16. Effect of welding thermal cycles on the structure and properties of simulated heat-affected zone areas in X10CrMoVNb9-1 (T91) steel at a state after 100,000 h of operation

    Energy Technology Data Exchange (ETDEWEB)

    Łomozik, Mirosław, E-mail: miroslaw.lomozik@is.gliwice.pl [Instytut Spawalnictwa, Testing of Materials Weldability and Welded Constructions Department, 44-100 Gliwice, Bł. Czesława 16-18 (Poland); Hernas, Adam, E-mail: adam.hernas@polsl.pl [Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, 40-019 Katowice, Krasińskiego 8 str. (Poland); Zeman, Marian L., E-mail: marian.zeman@is.gliwice.pl [Instytut Spawalnictwa, Testing of Materials Weldability and Welded Constructions Department, 44-100 Gliwice, Bł. Czesława 16-18 (Poland)

    2015-06-18

    The article presents results of structural tests (light, scanning electron and scanning transmission electron microscopy) of X10CrMoVNb9-1 (T91) creep-resisting steel after approximately 100,000 h of operation. It was ascertained that the parent metal of T91 steel is characterized by the microstructure of tempered martensite with M{sub 23}C{sub 6} carbide precipitates and few dispersive precipitates of MX-type niobium and vanadium carbonitrides. The most inconvenient change in T91 steel precipitate morphology due to long-term operation is the appearance of the Laves Fe{sub 2}Mo phase which along with M{sub 23}C{sub 6} carbide particles forms elongated blocks and conglomerates on grain boundaries. The article also presents results of tests related to the effect of simulated welding thermal cycles on selected properties of X10CrMoVNb9-1 (T91) grade steel at a state after approximately 100,000 h of operation. The tests involved the determination of the chemical composition of the steel tested as well as impact tests, hardness measurements and microscopic metallographic examination (based on light microscopy) of simulated heat-affected zone (HAZ) areas for a cooling time (t{sub 8/5}) restricted within a range between 3 s and 120 s, with and without heat treatment. The tests revealed that, among other results, hardness values of simulated HAZ areas in X10CrMoVNb9-1 (T91) steel do not guarantee cold crack safety of the steel at the state without additional heat treatment. It was also observed that simulated welding thermal cycles of cooling times t{sub 8/5}=3, 12, 60 and 120 s do not significantly affect the toughness and hardness of simulated HAZ areas of the steel tested.

  17. Paths to bioenergy villages. A guideline for a independent supply of heat and electricity based on biomass in rural area. 3. ed.; Wege zum Bioenergiedorf. Leitfaden fuer eine eigenstaendige Waerme- und Stromversrogung auf Basis von Biomasse im laendlichen Raum

    Energy Technology Data Exchange (ETDEWEB)

    Ruppert, Hans; Eigner-Thiel, Swantje; Girschner, Walter; Karpenstein-Machan, Marianne; Roland, Folker; Ruwisch, Volker; Sauer, Benedikt; Schmuck, Peter

    2010-12-15

    Bioenergy villages are one component for the sustainable energy supply in rural areas. The guideline under consideration is intended to encourage people in villages to switch their heat supply and electricity supply on the bases of biomass. The focus of this process-oriented guideline is on: (1) A presentation of the social feasibility, especially the involvement, motivation and encouragement of the population; (2) The presentation of concepts for a nature-friendly cultivation of the required biomass; (3) The treatment of economic and legal issues from the perspective of the people involved.

  18. Heat pumps

    CERN Document Server

    Macmichael, DBA

    1988-01-01

    A fully revised and extended account of the design, manufacture and use of heat pumps in both industrial and domestic applications. Topics covered include a detailed description of the various heat pump cycles, the components of a heat pump system - drive, compressor, heat exchangers etc., and the more practical considerations to be taken into account in their selection.

  19. High heat flux loop heat pipes

    Science.gov (United States)

    North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

    1997-01-01

    Loop Heat Pipes (LHPs) can transport very large thermal power loads, over long distances, through flexible, small diameter tubes and against high gravitational heads. While recent LHPs have transported as much as 1500 W, the peak heat flux through a LHP's evaporator has been limited to about 0.07 MW/m2. This limitation is due to the arrangement of vapor passages next to the heat load which is one of the conditions necessary to ensure self priming of the device. This paper describes work aimed at raising this limit by threefold to tenfold. Two approaches were pursued. One optimized the vapor passage geometry for the high heat flux conditions. The geometry improved the heat flow into the wick and working fluid. This approach also employed a finer pored wick to support higher vapor flow losses. The second approach used a bidisperse wick material within the circumferential vapor passages. The bidisperse material increased the thermal conductivity and the evaporative surface area in the region of highest heat flux, while providing a flow path for the vapor. Proof-of-concept devices were fabricated and tested for each approach. Both devices operated as designed and both demonstrated operation at a heat flux of 0.70 MW/m2. This performance exceeded the known state of the art by a factor of more than six for both conventional heat pipes and for loop heat pipes using ammonia. In addition, the bidisperse-wick device demonstrated boiling heat transfer coefficients up to 100,000 W/m2.K, and the fine pored device demonstrated an orientation independence with its performance essentially unaffected by whether its evaporator was positioned above, below or level with the condenser.

  20. 基于Landsat数据的昆明地区热岛效应分析%Analysis on the Urban Heat Island Effect of Kunming Area Based on Landsat Data

    Institute of Scientific and Technical Information of China (English)

    刘鑫; 甘淑

    2011-01-01

    The land surface temperature inversion of Kunming area had been put into practice based on Landsat TM data.; then it did a study on the intensity and spatial distribution of heat island effect.A quantitative analysis was done between land surface temperature and NDVI.The results show land surface temperature is closely related to the underlying surface type.Ways of reducing the heat island effect are discussed and improved the city thermal environment primarily.This research fill the gap of studies on city thermal environment of Kunming area based on remote sensing.%利用Landsat TM数据,对昆明地表温度进行反演.在此基础上分析了昆明地区热岛效应强度以及空间分布.定量研究了地表温度和植被指数的相关性.结果表明,地表温度与下垫面类型密切相关.初步探讨了降低热岛效应和改善热环境的途径.填补了昆明地区基于遥感城市热环境研究的空白.

  1. The Suitability Evaluation of Groundwater Heat Pump in the Urban Development Area of Wuhan%武汉市都市发展区地下水源热泵适宜性评价

    Institute of Scientific and Technical Information of China (English)

    胡元平; 刘红卫; 柯立; 朱志明; 马俊; 江凯; 李志鹏

    2014-01-01

    Using analytic hierarchy process to divide the suitability of groundwater heat pump in Wuhan urban develop -ment area,the paper selects aquifer effluent capacity ,permeability coefficient ,thickness of effective aquifer ,aquifer recir-culation capacity ,groundwater depth ,dynamic cjange of groundwater level ,water quality ,exploitation parameter ,karst col-lapse settlement for water table depression and the cost of well as evaluation index .Using 1-9 scaling method and expert evaluation method to determine weight ,establish evaluation system and composite index evaluation method .The evalua-tion result is that the suitable area include the front to middle of first grade terrace of Yangtze River and Hanjiang River , Baishazhou area ,South-Central steel rolling factory and other prohibition exploitation of groundwater area ,karst develop-ment area in Hannan ,the background of first grade terrace ,part of Covered Karst area are unsuitable areas of groundwater heat pump .%利用层次分析法开展武汉都市发展区地下水源热泵适宜性评价分区,根据武汉都市发展区地质环境条件,选取含水层出水能力、渗透系数、有效含水层厚度、含水层回灌能力、地下水位埋深、地下水位动态变化、地下水质量、结垢情况、开采模数、水位下降引起的环境地质问题(地面塌陷、沉降)和成井造价等11项作为评价指标。采用1~9标度法和专家打分确定权重,建立评价体系和综合指数评价方法。通过评价结果综合分析进行了适宜性分区,分区结果为地下水源热泵适宜区主要为长江、汉江一级阶地前缘—中缘;白沙洲地区、中南轧钢厂等地下水禁采区、汉南岩溶发育区、一级阶地后缘地区及部分隐伏岩溶区为不适宜区,为地下水源热泵的利用提供科学依据。

  2. Thermal energy storage application areas

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    The use of thermal energy storage in the areas of building heating and cooling, recovery of industrial process and waste heat, solar power generation, and off-peak energy storage and load management in electric utilities is reviewed. (TFD)

  3. Heat pumps

    CERN Document Server

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski

    2013-01-01

    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  4. Assessing the air quality impact of nitrogen oxides and benzene from road traffic and domestic heating and the associated cancer risk in an urban area of Verona (Italy)

    Science.gov (United States)

    Schiavon, Marco; Redivo, Martina; Antonacci, Gianluca; Rada, Elena Cristina; Ragazzi, Marco; Zardi, Dino; Giovannini, Lorenzo

    2015-11-01

    Simulations of emission and dispersion of nitrogen oxides (NOx) are performed in an urban area of Verona (Italy), characterized by street canyons and typical sources of urban pollutants. Two dominant source categories are considered: road traffic and, as an element of novelty, domestic heaters. Also, to assess the impact of urban air pollution on human health and, in particular, the cancer risk, simulations of emission and dispersion of benzene are carried out. Emissions from road traffic are estimated by the COPERT 4 algorithm, whilst NOx emission factors from domestic heaters are retrieved by means of criteria provided in the technical literature. Then maps of the annual mean concentrations of NOx and benzene are calculated using the AUSTAL2000 dispersion model, considering both scenarios representing the current situation, and scenarios simulating the introduction of environmental strategies for air pollution mitigation. The simulations highlight potentially critical situations of human exposure that may not be detected by the conventional network of air quality monitoring stations. The proposed methodology provides a support for air quality policies, such as planning targeted measurement campaigns, re-locating monitoring stations and adopting measures in favour of better air quality in urban planning. In particular, the estimation of the induced cancer risk is an important starting point to conduct zoning analyses and to detect the areas where population is more directly exposed to potential risks for health.

  5. In situ heat treatment process utilizing a closed loop heating system

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Nguyen, Scott Vinh (Houston, TX)

    2010-12-07

    Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

  6. Heat Pipe Systems

    Science.gov (United States)

    1993-01-01

    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  7. Magnetic fusion energy plasma interactive and high heat flux components. Volume I. Technical assessment of the critical issues and problem areas in the plasma materials interaction field

    International Nuclear Information System (INIS)

    A technical assessment of the critical issues and problem areas in the field of plasma materials interactions (PMI) in magnetic fusion devices shows these problems to be central for near-term experiments, for intermediate-range reactor devices including D-T burning physics experiments, and for long-term reactor machines. Critical technical issues are ones central to understanding and successful operation of existing and near-term experiments/reactors or devices of great importance for the long run, i.e., ones which will require an extensive, long-term development effort and thus should receive attention now. Four subgroups were formed to assess the critical PMI issues along four major lines: (1) PMI and plasma confinement physics experiments; (2) plasma-edge modelling and theory; (3) surface physics; and (4) materials technology for in-vessel components and the first wall. The report which follows is divided into four major sections, one for each of these topics

  8. HEAT RECUPERATION

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2011-01-01

    Full Text Available Heat recovery is an effective method of shortening specific energy consumption. new constructions of recuperators for heating and cupola furnaces have been designed and successfully introduced. two-stage recuperator with computer control providing blast heating up to 600 °C and reducing fuel consumption by 30% is of special interest.

  9. Appropriate technology for solar energy system aiming water heating for human bath in houses of rural areas; Tecnologia apropriada para sistema de energia solar visando aquecimento de agua para o banho humano em moradias do meio rural

    Energy Technology Data Exchange (ETDEWEB)

    Rispoli, Italo Alberto Gatica [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo], e-mail: gatica@dglnet.com.br; Mariotoni, Carlos Alberto [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Civil, Arquitetura e Urbanismo. Nucleo Interdisciplinar de Planejamento Energetico], e-mail: cam@fec.unicamp.br

    2004-07-01

    The Brazilian land receives a great amount of solar radiation all over the year, therefore, because both the culture and practical aspects, Brazilians use in a non-moderate way the electricity to boil the water for human bath in the rural homes, in the lower income residences even at part of the medium class homes. That happens due to the very low price of an electrical shower, about US$ 6,5. In fact, that way of heating water is largely used because, besides the very low electrical shower price, it is not necessary to install a complete hot water both hydraulic and electrical building systems, but just both single hydraulic pipes and electrical devices. On the other hands, at rural regions where the electricity does not achieve the rural people uses firewood in order to get hot water for human bath. At the rural places the use of electrical showers has meaning an increase in the electrical transformers powers, heavier electrical transmission rural lines, with greater prices and, at the urban zones, the use of electrical showers in the lower social classes has contributed to a more expressive electrical load at the nacional electrical system load peck, between 5:30 to 8:30 a.m. The public administration, mostly, does not take into account both social, economic and environmental costs in order to think about the electricity offer. The solar heating systems, generally used in Brazil, conserves the same reservoirs used in France at 1880. Therefore, this paper presents some technical subsidies applied to rural homes, even to lower income people's homes aiming to stimulate the Brazilian public authorities to make a public police to facilitate both the industrialization and dissemination of solar heating systems, appropriate to the rural area, with lower costs, compounded by good technology equipment, with guarantee of lasting and quality. (author)

  10. Heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Craig, L.B.; Farma, A.J.

    1987-01-06

    This invention concerns a heat exchanger as used in a space heater, of the type in which hot exhaust gases transfer heat to water or the like flowing through a helical heat exchange coil. A significant improvement to the efficiency of the heat exchange occurring between the air and water is achieved by using a conduit for the water having external helical fluting such that the hot gases circulate along two paths, rather than only one. A preferred embodiment of such a heat exchanger includes a porous combustion element for producing radiant heat from a combustible gas, surrounded by a helical coil for effectively transferring the heat in the exhaust gas, flowing radially from the combustion element, to the water flowing through the coil. 4 figs.

  11. 北京地区太阳能供暖系统集热器最佳倾角模拟分析%Simulation Analysis of the Best Angle for Solar Collector Heating System in Beijing Area

    Institute of Scientific and Technical Information of China (English)

    崔俊奎; 陈文婷

    2015-01-01

    According to the theory analysis of solar collector, using Polysun software, solar energy heat utilization dynamic simulation software, the paper analyzed and summarized the best angle and az-imuth angle for the collectors in Beijing area. A year-round best angle and azimuth angle is achieved for the flat solar collector.%对太阳能集热器进行理论分析,运用动态模拟软件Polysun对太阳能热利用进行仿真模拟,分析了北京地区集热器最佳倾角及其最佳方位角,计算得到全年使用时平板型太阳能集热器的最佳倾角及其最佳方位角。

  12. 唐山工业新区冬季采暖期大气污染变化特征研究%Variation of Air Pollution in New Tangshan Industrial Area During Winter Heating Period

    Institute of Scientific and Technical Information of China (English)

    周瑞; 辛金元; 邢立亭; 王晓元; 封孝信; 吉东生; 王跃思

    2011-01-01

    To illuminate the air pollution situation of the new Tangshan industrial area in the heating period,the observation of atmospheric pollutants was conducted in Tangshan City,Qianan City and Caofeidian Town from Oct.2009 to Apr.2010.The result showed that air pollution was serious in the area in winter.The regional mean concentration of NO,NO2,SO2,CO,PM2.5 and PM10 reached(26±28),(52±27),(72±53),(3 500±3 600),(82±65),(164±121)μg·m^-3 in the heating period,respectively.The concentration of NO and SO2 was 2.5 times in the heating period more than in the non-heating period.The concentration of NO2 and PM10 increased by ~30%.The rates that CO and PM10 exceeded the National Ambient Air Quality StandardⅡ were 27% and 40%;and the rate that PM2.5 exceeded the WHO IT1 Standard was 38%.The typical diurnal variations of NO,NO2,SO2,PM2.5 and PM10 were similar with peaking at 08:00 and 18:00,but the diurnal variation of CO was single peak at 08:00 with accumulating in evening.The peaks of NO,CO and SO2 were very high in morning because of the rush hours and the heating,which were 50,90,and 5 100μg·m^-3, respectively.The peaks of NO2,PM2.5and PM10 were relatively gentle,which were 56,105,and 202μg·m^-3,respectively.The cluster analysis of backward trajectories showed only the northerwinds,the cold airs can wash away the air pollution,while the southerwinds and easternwinds can easily accumulate the pollutants or transport the pollutants to the Beijing-Tianjin region.%为研究唐山工业新区采暖期大气污染变化状况,2009~2010年冬季唐山工业新区的唐山市、迁安市和曹妃甸3个地区观测研究表明,唐山工业新区冬季采暖期间大气污染严重,NO、NO2、SO2、CO、PM2.5和PM10区域平均日均值分别达到(26±28)、(52±27)、(72±53)、(3 500±3 600)、(82±65)和(164±121)μg·m^-3;NO和SO2平均浓度采暖期是采暖前后的2.5倍,NO2和PM10增长30%,CO和PM10日

  13. Minneapolis district-heating options

    Science.gov (United States)

    Stovall, T. K.; Borkowski, R. J.; Karnitz, M. A.; Strom, S.; Linwick, K.

    1981-10-01

    The feasibility of a large-scale district heating system for the Minneapolis central city area was investigated. The analysis was based on a previous city of St. Paul Hot-water district heating study and other studies done by a Swedish engineering firm. Capital costs such as building and heat source conversion, pipeline construction, and equipment were used in comparing the projected expenses of various district heating scenarios. Options such as coal, refuse-derived fuel burning, and cogeneration at the Riverside Power Station were discussed as energy supplies for a cost-effective district heating system.

  14. Flow and heat transfer enhancement in tube heat exchangers

    Science.gov (United States)

    Sayed Ahmed, Sayed Ahmed E.; Mesalhy, Osama M.; Abdelatief, Mohamed A.

    2015-11-01

    The performance of heat exchangers can be improved to perform a certain heat-transfer duty by heat transfer enhancement techniques. Enhancement techniques can be divided into two categories: passive and active. Active methods require external power, such as electric or acoustic field, mechanical devices, or surface vibration, whereas passive methods do not require external power but make use of a special surface geometry or fluid additive which cause heat transfer enhancement. The majority of commercially interesting enhancement techniques are passive ones. This paper presents a review of published works on the characteristics of heat transfer and flow in finned tube heat exchangers of the existing patterns. The review considers plain, louvered, slit, wavy, annular, longitudinal, and serrated fins. This review can be indicated by the status of the research in this area which is important. The comparison of finned tubes heat exchangers shows that those with slit, plain, and wavy finned tubes have the highest values of area goodness factor while the heat exchanger with annular fin shows the lowest. A better heat transfer coefficient ha is found for a heat exchanger with louvered finned and thus should be regarded as the most efficient one, at fixed pumping power per heat transfer area. This study points out that although numerous studies have been conducted on the characteristics of flow and heat transfer in round, elliptical, and flat tubes, studies on some types of streamlined-tubes shapes are limited, especially on wing-shaped tubes (Sayed Ahmed et al. in Heat Mass Transf 50: 1091-1102, 2014; in Heat Mass Transf 51: 1001-1016, 2015). It is recommended that further detailed studies via numerical simulations and/or experimental investigations should be carried out, in the future, to put further insight to these fin designs.

  15. Investigation on Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    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.......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...

  16. Radiative heat transfer

    CERN Document Server

    Modest, Michael F

    2013-01-01

    The third edition of Radiative Heat Transfer describes the basic physics of radiation heat transfer. The book provides models, methodologies, and calculations essential in solving research problems in a variety of industries, including solar and nuclear energy, nanotechnology, biomedical, and environmental. Every chapter of Radiative Heat Transfer offers uncluttered nomenclature, numerous worked examples, and a large number of problems-many based on real world situations-making it ideal for classroom use as well as for self-study. The book's 24 chapters cover the four major areas in the field: surface properties; surface transport; properties of participating media; and transfer through participating media. Within each chapter, all analytical methods are developed in substantial detail, and a number of examples show how the developed relations may be applied to practical problems. It is an extensive solution manual for adopting instructors. Features: most complete text in the field of radiative heat transfer;...

  17. Heat exchanger network retrofit through heat transfer enhancement

    OpenAIRE

    Wang, Yufei

    2012-01-01

    Heat exchanger network retrofit plays an important role in energy saving in process industry. Many design methods for the retrofit of heat exchanger networks have been proposed during the last three decades. Conventional retrofit methods rely heavily on topology modifications which often results in a long retrofit duration and high initial costs. Moreover, the addition of extra surface area to the heat exchanger can prove difficult due to topology, safety and downtime constraints. These probl...

  18. Heat recovery apparatus

    International Nuclear Information System (INIS)

    Heat transfer is a living science and technical advances are constantly being made. However, in many cases, progress is limited by the equipment that is available on the market, rather than by knowledge of the heat transfer process. A case in point is the design of economizers: in such equipment a small quantity of water (with a relatively good heat transfer coefficient) is heated by a large quantity of low-pressure gas (with an inherently low heat transfer coefficient). As a first step in design finned tubing is used to lessen the discrepancy in coefficients. From this point, it becomes apparent that the equipment consists of a small number of tubes (to maintain good velocity on the water side) of considerable length (to provide sufficient area). In the process industries the base pressure, though low, may be in the region of 0.5 bar, and there is no convenient flue in which to place the heat recovery coil. It is therefore contained in a flat-sided enclosure, which is ill-fitted to pressure containment and is therefore reinforced with a plethora of structural sections. Such inelegant construction is quite common in North America; in Europe, cylindrical containments of vast size have been supplied for the same purposes. The real shortcoming is a successful marriage of different disciplines to produce reliable and efficient heat transfer equipment suitably contained

  19. Hydrology and numerical simulation of groundwater movement and heat transport in Snake Valley and surrounding areas, Juab, Miller, and Beaver Counties, Utah, and White Pine and Lake Counties, Nevada

    Science.gov (United States)

    Masbruch, Melissa D.; Gardner, Philip M.; Brooks, Lynette E.

    2014-01-01

    Snake Valley and surrounding areas, along the Utah-Nevada state border, are part of the Great Basin carbonate and alluvial aquifer system. The groundwater system in the study area consists of water in unconsolidated deposits in basins and water in consolidated rock underlying the basins and in the adjacent mountain blocks. Most recharge occurs from precipitation on the mountain blocks and most discharge occurs from the lower altitude basin-fill deposits mainly as evapotranspiration, springflow, and well withdrawals. The Snake Valley area regional groundwater system was simulated using a three-dimensional model incorporating both groundwater flow and heat transport. The model was constructed with MODFLOW-2000, a version of the U.S. Geological Survey’s groundwater flow model, and MT3DMS, a transport model that simulates advection, dispersion, and chemical reactions of solutes or heat in groundwater systems. Observations of groundwater discharge by evapotranspiration, springflow, mountain stream base flow, and well withdrawals; groundwater-level altitudes; and groundwater temperatures were used to calibrate the model. Parameter values estimated by regression analyses were reasonable and within the range of expected values. This study represents one of the first regional modeling efforts to include calibration to groundwater temperature data. The inclusion of temperature observations reduced parameter uncertainty, in some cases quite significantly, over using just water-level altitude and discharge observations. Of the 39 parameters used to simulate horizontal hydraulic conductivity, uncertainty on 11 of these parameters was reduced to one order of magnitude or less. Other significant reductions in parameter uncertainty occurred in parameters representing the vertical anisotropy ratio, drain and river conductance, recharge rates, and well withdrawal rates. The model provides a good representation of the groundwater system. Simulated water-level altitudes range over

  20. Capillary-Condenser-Pumped Heat-Transfer Loop

    Science.gov (United States)

    Silverstein, Calvin C.

    1989-01-01

    Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

  1. Variable Heat Rejection Loop Heat Pipe radiator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal control systems are sized for the maximum heat load in the warmest continuous environment. This design process results in a larger radiator surface area...

  2. 成都某住宅小区会所地源热泵空调系统设计%Design of HVAC of ground-source heat pump air conditioning system for A club of a residential area in Chengdu

    Institute of Scientific and Technical Information of China (English)

    周伟军; 张歆晖; 杨青松; 陈舒婷

    2015-01-01

    A club of a residential area in Chengdu has used the buried pipeground-source heat pump air conditioning system .The buried pipe is set up under the raft board of the underground garagestructural. There are six modularground-source heat pump units and a host selection of the entire heat recovery modular ground-source heat pump units adopted in the system which provides air conditioning heat/coldsources, living hot water heat source and indoor heatedswimming pool with heating desiccant cooling and heat sources for the club.%成都某住宅小区内会所,采用地埋管地源热泵空调系统。地埋管设于小区地下汽车库结构筏板下。系统采用6台模块式地源热泵机组,1台全热回收地源热泵机组,为整个会所提供空调冷热源、生活热水热源及室内恒温泳池除湿加热冷热源。

  3. Effect of Localized Heating on Three-Dimensional Flat-Plate Oscillating Heat Pipe

    OpenAIRE

    Ma, H. B.; Thompson, S.M.

    2010-01-01

    An experimental investigation was conducted, both thermally and visually, on a three-dimensional flat-plate oscillating heat pipe (3D FP-OHP) to characterize its performance under localized heat fluxes while operating in the bottom heating mode and charged with acetone at a filling ratio of 0.73. The cooling area was held constant and three heating areas of 20.16 cm2, 11.29 cm2, and 1.00 cm2 were investigated, respectively. It was found that as the heating area was reduced and higher heat flu...

  4. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1994-01-01

    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  5. Heat exchanger restart evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

    1992-02-28

    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4kA was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized herein.

  6. Magnetar heating

    CERN Document Server

    Beloborodov, Andrei M

    2016-01-01

    We examine four candidate mechanisms that could explain the high surface temperatures of magnetars. (1) Heat flux from the liquid core heated by ambipolar diffusion. It could sustain the observed surface luminosity $L_s\\approx 10^{35}$ erg s$^{-1}$ if core heating offsets neutrino cooling at a temperature $T_{\\rm core}>6\\times 10^8$ K. This scenario is viable if the core magnetic field exceeds $10^{16}$ G, the magnetar has mass $M10^{16}$ G varying on a 100 meter scale could provide $L_s\\approx 10^{35}$ erg s$^{-1}$. (4) Bombardment of the stellar surface by particles accelerated in the magnetosphere. This mechanism produces hot spots on magnetars. Observations of transient magnetars show evidence for external heating.

  7. Conjugate Heat Transfer in a Closed Volume with the Local Heat Sources and Non-Uniform Heat Dissipation on the Boundaries of Heat Conducting Walls

    Science.gov (United States)

    Maksimov, Vyacheslav I.; Nagornova, Tatiana A.; Glazyrin, Viktor P.

    2016-02-01

    Is solved the problem of heat transfer in the closed volume, limited by heat-conducting walls, with the local source of heat emission and the heterogeneous conditions of heat sink on the outer boundaries of solution area. The problem of convective heat transfer is solved with using a system of differential Navier-Stokes equations in the Boussinesq approximation. The simulation of turbulent flow conditions of heated air is carried out within the framework to k-ɛ model. On the basis the analysis of the obtained temperature field and the contour lines of stream functions is made conclusion about the essential transiency of the process in question. The obtained values of temperatures and speeds in different sections of region illustrate turbulence of the process. Are investigated laws governing the formation of temperature fields in closed areas with a local heat emission source under the conditions of intensive local heat sink into environment and accumulation of heat in the enclosing constructions.

  8. New CO{sub 2} neutral city area with integrated district heating system of the future in Hoeje Taastrup - Phase 1: Preparation of demonstration. Final report; Denmark; Ny CO{sub 2}-neutral bydel med fremtidens integrerede fjernvarmesystem i Hoeje Taastrup - Fase 1: Forberedelse af demonstration. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Kaarup Olsen, P.; Hummelshoej, R.M. (Cowi A/S (Denmark))

    2011-02-15

    three options are interesting. The 'return heat the solution' has less CO{sub 2} displacement potential, but will require a minimal investment cost compared to a regular connection to the HTF/VEKS district heating network. With the assumptions used, the solution with heat-powered pumps and a central solar heating plant provides t a considerably lower CO{sub 2} displacement price than a solution with central ground and solar heating. It is therefore recommended to further analyse the solution with a heat driven heat pump. To make the energy supply of the district CO{sub 2} neutral in the short term, it will be necessary to install wind turbines with a total capacity of approx. 6 MW, which for that particular area at this time would be the most cost-effective solution, i.e. will have the lowest CO{sub 2} displacement price. (LN)

  9. Heat Rash or Prickly Heat (Miliaria Rubra)

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Heat Rash or Prickly Heat (Miliaria Rubra) Information for adults A A A ... bumps can suddenly occur, as seen here. Overview Heat rash (miliaria rubra), also known as prickly heat, ...

  10. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav

    2012-04-01

    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  11. Heat exchanger leakage problem location

    Science.gov (United States)

    Hejčík, Jiří; Jícha, Miroslav

    2012-04-01

    Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  12. Large-scale solar heating

    Energy Technology Data Exchange (ETDEWEB)

    Tolonen, J.; Konttinen, P.; Lund, P. [Helsinki Univ. of Technology, Otaniemi (Finland). Advanced Energy Systems

    1998-10-01

    Solar heating market is growing in many European countries and annually installed collector area has exceeded one million square meters. There are dozens of collector manufacturers and hundreds of firms making solar heating installations in Europe. One tendency in solar heating is towards larger systems. These can be roof integrated, consisting of some tens or hundreds of square meters of collectors, or they can be larger centralized solar district heating plants consisting of a few thousand square meters of collectors. The increase of size can reduce the specific investments of solar heating systems, because e.g. the costs of some components (controllers, pumps, and pipes), planning and installation can be smaller in larger systems. The solar heat output can also be higher in large systems, because more advanced technique is economically viable

  13. 北方农村地区火墙兼生活热水系统应用实验研究%Experimental Study on Application of Hot Wall with Heating Water System in North Rural Area

    Institute of Scientific and Technical Information of China (English)

    吴雨婷; 王万江; 齐典伟

    2015-01-01

    The hot wall system includes a stove (or furnace), firewall, chimney, as one kind of building traditional heating system, in recent years, is still the main forms of supply heating in most of the Xinjiang rural area. For the moment, the wall construction based on mainly experience. and has large differences in performance, A common problem with hot wall is that:high temperature of exhaust gas, energy consumption, low energy utilization rate. This article in view of the above shortcomings, the hot wall and domestic hot water system is proposed, arrangementin the copper tube in the original wall as new system. At different outdoor temperatures and the indoor thermal comfort conditions needs, the energy efficiency of new system were studied and compared with the traditional hot wall. The experimental results show that, the new hot wall and domestic hot water system can ensure indoor thermal comfort at the same time can heat domestic water use flue gas, reducing the exhaust gas temperature, the energy utilization rate is improved obviously. It is of certain significance to promotion and intensive study.%火墙系统包括炉灶(或火炉)、火墙、烟囱,作为一种建筑传统供暖系统,近年来,依然是新疆大部分农村地区民居采用的主要供暖形式。目前使用的火墙,建造多以经验为指导,性能参差不齐,普遍存在排烟温度高,能耗大,能源利用率低的缺点。本文针对上述缺点,提出了供暖火墙兼生活热水系统,即在原有火墙中加入了生活热水加热铜盘管。在不同室外温度下,满足室内热舒适性条件下,对该系统的能源利用率进行了实验研究并与传统火墙进行了对比。实验结果表明,供暖火墙兼生活热水系统的新式火墙能在保证室内热舒适性的同时又可以用烟气加热生活用水,降低了排烟温度,明显提高能源利用率,具有现实的推广和深入研究的意义。

  14. Analysis of a Flooded Heat Exchanger

    Science.gov (United States)

    Fink, Aaron H.; Luyben, William L.

    2015-01-01

    Flooded heat exchangers are often used in industry to reduce the required heat-transfer area and the size of utility control valves. These units involve a condensing vapor on the hot side that accumulates as a liquid phase in the lower part of the vessel. The heat transfer occurs mostly in the vapor space, but the condensate becomes somewhat…

  15. HEAT TRANSFER ENHANCEMENT OF SMALL SCALE HEAT SINKS USING VIBRATING PIN FIN

    OpenAIRE

    Suabsakul Gururatana; Xianchang Li

    2013-01-01

    Heat sinks are widely adopted in electronics cooling together with different technologies to enhance the cooling process. For the small electronics application, the small scale pin fins heat sinks are extensively used to dissipate heat in electronics devices. Due to the limit of space in the small devices, it is impossible to increase heat transfer area. In order to improve the heat transfer performance, the applying the forced vibration is one of challenging method. This study applies the vi...

  16. Measurement of flow field and local heat transfer distribution on a scraped heat exchanger crystalliser surface

    OpenAIRE

    Rodriguez, Marcos; Ravelet, Florent; Delfos, Rene; Witkamp, Geert-Jan

    2008-01-01

    In a cylindrical scraped heat exchanger crystallizer geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat exchanger surface has been studied by direct measurements of the heat exchanger surface temperature and the fluid velocity field inside the crystallizer. Liquid Crystal Thermometry revealed that the local heat transfer is higher in the middle area of the scraped surface. Stereoscopic PIV measurements demonstrated that the secondary flo...

  17. Heat exchanger

    International Nuclear Information System (INIS)

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections

  18. Heat transfer

    CERN Document Server

    Holman, J P

    2010-01-01

    As one of the most popular heat transfer texts, Jack Holman's "Heat Transfer" is noted for its clarity, accessible approach, and inclusion of many examples and problem sets. The new tenth edition retains the straight-forward, to-the-point writing style while covering both analytical and empirical approaches to the subject. Throughout the book, emphasis is placed on physical understanding while, at the same time, relying on meaningful experimental data in those situations that do not permit a simple analytical solution. New examples and templates provide students with updated resources for computer-numerical solutions.

  19. Analysis of the Christian Belief Heat in Rural Areas and Social Work Interference%农村基督教信仰热现象探析与社会工作干预

    Institute of Scientific and Technical Information of China (English)

    赵建玲; 王书敏

    2012-01-01

    The aim was to make people comprehend Christian belief rationally, and lead coordinate development of Christian belief and socialist society, using the method of literature analysis, about the phenomenon of Christian belief heat in rural area, the reasons from the society, personal and the attraction of Christianity, and the complex influences to the rural society. Some countermeasures were put forward from the perspective of social work interference to reduce the negative effects, such as improving peasant' s overall quality, executing the social security system effectively, understanding the Christianity correctly. Other countries' Christian belief practice could be used as reference and guidance for Chinese Christian belief.%为使社会公众对于农村基督教信仰热现象有一种理性的认识,引导基督教与社会主义社会协调发展,利用文献分析的方法,就农村基督教信仰热的现象从社会、个人、基督教的吸引力等3方面探讨了其产生的原因和对农村社会发展带来的复杂影响,针对其负面影响从社会工作干预的视角提出了若干相应对策,如提高农民综合素质,促进社会保障制度的有效实施,端正信徒对于基督教的认识等.最后介绍了世界其他国家的基督教信仰情况对中国的借鉴与指导意义.

  20. Combination solar photovoltaic heat engine energy converter

    Science.gov (United States)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  1. 黄海北部海水源热泵供热和免费供冷系统实测%Field Measurement on a Seawater Source Heat PumP System for Heating of Buildings and a Free Cooling System in Coastal Area of the Northern Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    贾欣; 端木琳; 舒海文; 任志勇; 徐策; 刘靓侃; 王飞帆

    2014-01-01

    Seawater source heat pump system (SWHP) is a renewable energy utilization system.But it is lack of practical application study about the system up to now.In this study, a SWHP system in coastal area of the northern Yellow Sea was measured.The winter measurement results showed that the average heating COP of a heat pump unit and the whole system were 2.43 and 1.86 respectively dur_ing the measurement period while the corresponding COP were 2.99 and 2.30 respectively during the whole heating season.The summer measurement results showed that the average cooling COP of the system was 3.35 during the measurement period.This paper further ana_lyzed the major cause of the low free cooling system COP, and it is that the fan coil units are not selected by actual seawater temperature, which leads to the low supply and return water temperature difference (only 1 ℃) and high circulating pump energy consumption.%海水源热泵区域供热供冷系统作为一项可再生能源利用技术,目前尚缺乏有关该系统实际应用方面的研究。作者对黄海北部某海水源热泵区域供热供冷系统进行了实地调研与测试,获得了该系统运行方面的大量第一手数据,经计算得到;2013年冬季极端海水温度期间,所测试热泵机组的实际平均制热性能系数为2.43,相应工况下的系统平均制热性能系数为1.86;2011—2012年供暖季机组和系统的平均制热性能系数分别为2.99和2.30;夏季“免费”供冷(热泵机组不开启)测试期间,系统的平均制冷性能系数为3.35。文章进一步对夏季“免费”供冷期间系统制冷性能系数不高的原因进行了分析。分析结果表明,由于用户的风机盘管未按实际冷水温度选择,致使实际运行时冷水供﹑回水温差仅有1℃,从而导致水泵运行能耗过高。

  2. 多斜孔截面面积变化对孔内流动与换热特性的影响%Influence of Flow and Heat Transfer Characteristics to Inclined Multi Holes Section Area Change in Holes

    Institute of Scientific and Technical Information of China (English)

    王飞; 张勃; 吉洪湖; 刘红梅; 赵传亮

    2014-01-01

    对多斜孔内部流通截面面积进行了对比分析,设计了5种流通面积沿程变化模型,分别为不变(圆柱型)、逐渐减小(渐缩圆台形)、先增大后减小(外凸形)、先减小后增大(内凹形)、逐渐增大(渐扩圆台形)。通过数值模拟研究了其对斜孔内流动与换热特性的影响。结果表明:多斜孔内部流通截面的变化使得其孔内气流压力、流动以及微团流动规律发生显著变化;在截面积由渐缩变为渐扩的过程中,流体微团在出口处转动方向由顺时针转为逆时针;流通面积的扩大使得压力沿程逐渐降低,在多斜孔出口下游形成低压区,出口气膜附壁性增强,气膜冷却效果增强;在多斜孔内,流通面积的扩大使得斜孔内壁背风面压力较大、流速较大、对流换热较强,斜孔内壁迎风面流体脱壁,换热较弱。%Five effusion cooled Plates in which the cross-sectional area of the hole continuously changed( circle,taPered cone,convex outside,concave inside and divergent cone)were designed to study the flow and heat transfer characteristics in the hole. The results show that the change of the cross-sectional area in the effusion hole leads to the corresPonding changes of Pressure and the flow characteristic of fluid element in the hole. With the flow area in the hole changes from taPer into di-vergence,the rotation direction of fluid element changes from clockwise to counterclockwise at the ex-it,the exPansion of flow area makes the Pressure lower along,and the Pressure on the lower reaches of the exit is low,which enhances the Coanda effect and film cooling effectiveness. The Pressure on leeward side of the effusion hole is larger,and the cooling effect is better,while on the windward side,the fluid takes off the wall,the Pressure is lower and the cooling effect is worse.

  3. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... for signs of heat stroke or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms ... heavy sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, ...

  4. I Using Porous Material for Heat Transfer Enhancement in Heat Exchangers: Review

    Directory of Open Access Journals (Sweden)

    M. A. Delavar

    2013-01-01

    Full Text Available The increase in energy cost and energy consumption has required more effective use of energy. The problem of dissipating high heat fluxes has received much attention due to its importance in applications such as heat exchanger. The heat transfer duty of heat exchangers can be improved by heat transfer enhancement techniques. In recent years, Considerable efforts have been made to increase heat transfer rates in heat exchangers by implementing passive enhancement methods that require no direct consumption of external power. On the basis of a theoretical and experimental analysis the conclusion derived was that the best heat transfer enhancement can be reached by the use of porous material as an inexpensive technique to extend the heat transfer area, improve effective thermal conductivity, and mix fluid flow. This paper presents a brief discussion on the application of using porous media to heat exchangers by means of heat transfer enhancement.

  5. Atmospheric pollution and heating plants in urban area. What technical solutions for the coal and the heavy oil? For which costs?; Pollution atmospherique et chaufferies en milieu urbain. Quelles solutions techniques pour le charbon et le fioul lourd?. A quel couts?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    In France, furnaces fed with coal and heavy fuel and established in urban area, are bound by many restraints: a reinforcement of the regulations on atmospheric emissions, a strong social demand bound to the urban air quality improvement and a necessary costs mastership. So buildings managers and persons responsible for district heating are confronted with technical and strategical choices. To answer their questions ADEME organized a day of information around four main themes: the urban heating in France, actions on fuels, possible technics for the smokes desulfurization and nitrogen oxides reduction, costs and financing of the solutions. (A.L.B.)

  6. Development, Testing, and Application of a Coupled Hydrodynamic Surface-Water/Groundwater Model (FTLOADDS) with Heat and Salinity Transport in the Ten Thousand Islands/Picayune Strand Restoration Project Area, Florida

    Science.gov (United States)

    Swain, Eric D.; Decker, Jeremy D.

    2009-01-01

    A numerical model application was developed for the coastal area inland of the Ten Thousand Islands (TTI) in southwestern Florida using the Flow and Transport in a Linked Overland/Aquifer Density-Dependent System (FTLOADDS) model. This model couples a two-dimensional dynamic surface-water model with a three-dimensional groundwater model, and has been applied to several locations in southern Florida. The model application solves equations for salt transport in groundwater and surface water, and also simulates surface-water temperature using a newly enhanced heat transport algorithm. One of the purposes of the TTI application is to simulate hydrologic factors that relate to habitat suitability for the West Indian Manatee. Both salinity and temperature have been shown to be important factors for manatee survival. The inland area of the TTI domain is the location of the Picayune Strand Restoration Project, which is designed to restore predevelopment hydrology through the filling and plugging of canals, construction of spreader channels, and the construction of levees and pump stations. The effects of these changes are simulated to determine their effects on manatee habitat. The TTI application utilizes a large amount of input data for both surface-water and groundwater flow simulations. These data include topography, frictional resistance, atmospheric data including rainfall and air temperature, aquifer properties, and boundary conditions for tidal levels, inflows, groundwater heads, and salinities. Calibration was achieved by adjusting the parameters having the largest uncertainty: surface-water inflows, the surface-water transport dispersion coefficient, and evapotranspiration. A sensitivity analysis did not indicate that further parameter changes would yield an overall improvement in simulation results. The agreement between field data from GPS-tracked manatees and TTI application results demonstrates that the model can predict the salinity and temperature

  7. Distribution of heat gain and direction for energy efficiency of residential buildings in hot summer and cold winter area%夏热冬冷地区居住建筑房间得热量分布及节能方向

    Institute of Scientific and Technical Information of China (English)

    金斯科; 龚延风

    2012-01-01

    Analyses and calculates the hourly heat transfer through each building envelope and the proportion of it to the total heat gain for the four rooms with the response factor method for multi-layer wall thermodynamic system under a typical weather condition in Nanjing. The results show that in the typical summer weather condition, the influence of unit area building envelope on the room heat gain is, in a descending order, radiant heat gain through the window, heat transfer through the window, heat transfer through the roof, heat transfer through the west/east wall, heat transfer through the south wall; the heat gain from solar radiation is always the main portion in daytime; the hourly heat gain through west windows caused by radiation and transfer increases significantly with the increase of the west window-wall area ratios in this area, it is suggested to improve the performance of the window shading, to reduce the heat transfer coefficient of the window, to properly control the area of the south window, and to strictly control the window-wall area ratio of the west/east wall, and the west window-wall area ratio should not be greater than 0.2.%采用多层板壁热力系统的反应系数法分析计算了典型气象条件下4个典型房间各围护结构的逐时传热量及其在房间得热量中所占比例.结果显示,在夏季典型气候条件下,单位面积围护结构对房间得热量的影响从大到小依次为外窗太阳辐射、外窗传热、屋顶传热、东西墙传热、南墙传热;白天由太阳辐射引起的得热量一直是房间得热量的主要部分;随着西向窗墙面积比的增大,西窗逐时传热得热量和辐射得热量呈线性显著增加;在夏热冬冷地区,必须提高窗户的遮阳性能,并降低窗户的传热系数,适当控制南向窗户面积,严格控制东西向窗墙面积比,建议西向窗墙面积比不大于0.2.

  8. Optimal Allocation of Heat Exchanger Inventory Associated with Fixed Power Output or Fixed Heat Transfer Rate Input

    Directory of Open Access Journals (Sweden)

    M. Costea

    2002-03-01

    Full Text Available The purpose of this study is to determine the optimal distribution of the heat transfer surface area or conductance among the Stirling engine heat exchangers when the minimum of the total heat transfer surface area of the heat exchangers is sought. The optimization procedure must fulfill one of the following constraints: (1 fixed power output of the engine, (2 fixed heat transfer rate available at the source, or (3 fixed power output and heat transfer rate at the source. Internal and external irreversibilities of the Stirling engine are considered. An analytic approach, when heat transfer occurs at small temperature differences at the heat reservoirs, provides several restrictions with regard to variables of the model. A sensitivity analysis of the minimum of the total heat transfer surface area of the heat exchangers with respect to these variables and parameters is presented. The results show optimal temperatures of the working fluid and optimum allocation of heat exchanger inventory.

  9. Optimized high-temperature cathode-heating unit

    International Nuclear Information System (INIS)

    Description of structure and test results of cathode-heating unit for electron accelerators are presented. In the given cathode unit LaB6 cathode area is enlarged, efficient heat isolations are used, heating element stiffness and strength are increased. Compact shild packets are used in a cathode unit. The heating element is made in the form of concentric rings. The unit heat efficiency is >80%, nonisothermality ΔT2 emitter area at T=2050 K constituted 700 h

  10. Vibration isolation of dimple plate heat exchangers / Pieter Vergeer

    OpenAIRE

    Vergeer, Pieter

    2012-01-01

    Dimple plate heat exchangers are a new type of welded compact plate heat exchangers. The dimple plates increase the turbulence of the fluid flowing over the plate, increasing the efficiency of the heat exchanger without increasing pressure drop over the heat exchanger. The compact design of the heat exchanger makes it possible to install the heat exchanger at the top of condenser columns, reducing the footprint area of the column by replacing standard shell and tube condense...

  11. NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Holck, Ole; Svendsen, Svend

    2003-01-01

    In this paper, heat storage of solar heating in the floor construction of single-family houses is examined. A floor construction with two concrete decks is investigated. The lower is used as heat storage while the upper deck has a floor heating system. The potential for a reduction of the energy...... consumption for heating, by using heat storage in the floor construction is calculated using a dynamic simulation model of solar collector, solar tank and heat storage coupled to a building model, using the Danish Design Ref-erence Year as input. The model calculates the performance of the solar heating...... system room temperature and energy consumption. A single-family house with and without heat recovery unit on the ventilation system of 130 m² with heating demand of approximately 70 kWh/m² and 40 kWh/m² is investigated. A parametrical analysis was performed for the solar collector area, and floor layouts...

  12. 'Heat Dome' Heats Up United States

    Science.gov (United States)

    ... news/fullstory_160028.html 'Heat Dome' Heats Up United States Much of the country to be under ... As a massive "heat dome" stretches across the United States this week, sending temperatures and humidity levels ...

  13. 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.

  14. Earth's surface heat flux

    Directory of Open Access Journals (Sweden)

    J. H. Davies

    2009-11-01

    Full Text Available We present a revised estimate of Earth's surface heat flux that is based upon a heat flow data-set with 38 347 measurements, which is 55% more than used in previous estimates. Our methodology, like others, accounts for hydrothermal circulation in young oceanic crust by utilising a half-space cooling approximation. For the rest of Earth's surface, we estimate the average heat flow for different geologic domains as defined by global digital geology maps; and then produce the global estimate by multiplying it by the total global area of that geologic domain. The averaging is done on a polygon set which results from an intersection of a 1 degree equal area grid with the original geology polygons; this minimises the adverse influence of clustering. These operations and estimates are derived accurately using methodologies from Geographical Information Science. We consider the virtually un-sampled Antarctica separately and also make a small correction for hot-spots in young oceanic lithosphere. A range of analyses is presented. These, combined with statistical estimates of the error, provide a measure of robustness. Our final preferred estimate is 47±2 TW, which is greater than previous estimates.

  15. Designing and operating optimization of ground-source heat pump system in severe cold area%严寒地区地埋管地源热泵系统设计及运行优化

    Institute of Scientific and Technical Information of China (English)

    刘逸; 李炳熙; 付忠斌; 方明洙

    2011-01-01

    Makes a heating condition optimizing experiment for a ground-source heat pump system, and the results show that heat pump and underground heat-exchanger reach steady-state after 6 hours and heat absorption of underground heat-exchanger per meter depth is 24. 5 W/m under the continuous operation condition! The ground temperature can restore in time! The OOP of the system is increased by 4.34% and the COP of the heat pump is increased by 3.23%; the COP of the system and heat pump are highest when two compressors operating, respectively are 12.2% and 11% higher than that of four compressors; the COP of the system is increased by 12.5% when two compressors operate and the circulating pumps adopt the inverter control and the COP of the heat pump is increased by 6.42% when three compressors operate and the circulating pumps adopt the inverter control under intermittent operation condition.%对某地埋管地源热泵系统冬季供热工况进行了优化实验.结果表明,系统连续运行时,6h后机组和地埋管换热器达到稳定状态,地埋管换热器单位埋深的取热量为24.5W/m;系统间歇运行时,土壤温度能及时恢复,系统的COP提高4.34%,机组的COP提高3.23%,2台压缩机工作时系统和机组的COP值最大,比4台压缩机工作时分别高12.2%和11%,2台压缩机运行、循环泵采用变频控制时,系统COP提高了12.5%;3台压缩机运行、循环泵采用变频控制时,系统COP提高了6.42%.

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

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

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

  17. Field performance of a premium heating oil

    Energy Technology Data Exchange (ETDEWEB)

    Santa, T. [Santa Fuels, Inc., Bridgeport, CT (United States); Jetter, S.M. [Mobil Oil R & D Corp., Paulsboro, NJ (United States)

    1996-07-01

    As part of our ongoing research to provide quality improvements to heating oil, Mobil Oil together with Santa Fuel, Inc., conducted a field trial to investigate the performance of a new premium heating oil. This premium heating oil contains an additive system designed to minimize sludge related problems in the fuel delivery system of residential home heating systems. The additive used was similar to others reported at this and earlier BNL conferences, but was further developed to enhance its performance in oil heat systems. The premium heating oil was bulk additized and delivered to a subset of the customer base. Fuel related, unscheduled service calls were monitored in this test area, as well as in a similar baseline area that did not receive the premium heating oil. Overall, the premium fuel provided a 45% reduction in the occurrence of fuel related, unscheduled service calls as compared to the baseline area. Within this population, there was a reduction of 38% in systems with 275 gallon tanks, and 55% in systems that had >275 gallon tanks showing that the additive is effective in the various configurations of residential oil heat systems. In addition, photographic documentation collected at two accounts supported this improvement by clearly showing that the equipment remained cleaner with the premium heating oil than with regular heating oil. Based on these results, a full marketing trial of this new product has been initiated by Mobil and Santa Fuel, Inc., during the 1995-1996 heating season.

  18. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  19. Heating systems for heating subsurface formations

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  20. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1982-01-01

    A comprehensive, up-to-date coverage of the theory, design and manufacture of heat pipes and their applications. This latest edition has been thoroughly revised, up-dated and expanded to give an in-depth coverage of the new developments in the field. Significant new material has been added to all the chapters and the applications section has been totally rewritten to ensure that topical and important applications are appropriately emphasised. The bibliography has been considerably enlarged to incorporate much valuable new information. Thus readers of the previous edition, which has established

  1. Heat transfer

    CERN Document Server

    Jorge, Kubie; Thomas, Grassie

    2012-01-01

    A core task of engineers is to analyse energy related problems. The analytical treatment is usually based on principles of thermodynamics, fluid mechanics and heat transfer, but is increasingly being handled computationally.This unique resource presents a practical textbook, written for both undergraduates and professionals, with a series of over 60 computer workbooks on an accompanying CD.The book emphasizes how complex problems can be deconstructed into a series of simple steps. All thermophysical property computations are illustrated using diagrams within text and on the compani

  2. Thermal design heat sinks, thermoelectrics, heat pipes, compact heat exchangers, and solar cells

    CERN Document Server

    Lee, H S

    2010-01-01

    The proposed is written as a senior undergraduate or the first-year graduate textbook,covering modern thermal devices such as heat sinks, thermoelectric generators and coolers, heat pipes, and heat exchangers as design components in larger systems. These devices are becoming increasingly important and fundamental in thermal design across such diverse areas as microelectronic cooling, green or thermal energy conversion, and thermal control and management in space, etc. However, there is no textbook available covering this range of topics. The proposed book may be used as a capstone design cours

  3. Heat waves in urban heat islands: interactions, impacts, and mitigation

    Science.gov (United States)

    Bou-Zeid, E.; Li, D.

    2013-12-01

    Urbanization rates and the intensity of anthropogenic global warming are both on the rise. By the middle of this century, climate change impacts on humans will be largely manifested in urban regions and will result from a combination of global to regional impacts related to greenhouse gas emissions, as well as regional to local impacts related to land-cover changes associated with urbanization. Alarmingly, our understanding of how these two distinct impacts will interact remains very poor. One example, which is the focus of this study, is the interaction of urban heat islands and heat waves. Urban heat islands (UHIs) are spatial anomalies consisting of higher temperatures over built terrain; while their intensity varies with many factors, it consistently increases with city size. UHIs will hence intensify in the future as cities expand. Heat waves are temporal anomalies in the regional temperatures that affect both urban and rural areas; there is high certainty that the frequency and intensity of such waves will increase as a result global warming. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses of a heat wave event over the Baltimore-Washington urban corridor reveals synergistic interactions between urban heat islands and heat waves. Not only do heat waves increase the regional temperatures, but they also intensify the difference between urban and rural temperatures. That is, their impact is stronger in cities and the urban heat stress during such waves is larger than the sum of the background urban heat island effect and the heat wave effect. We also develop a simple analytical model of this interaction that suggests that this exacerbated impact in urban areas is primarily to the lack of surface moisture, with low wind speeds also playing a smaller role. Finally, the effectiveness of cool and green roofs as UHI mitigation

  4. Silicon Ingot Casting - Heat Exchanger Method Multi-wire Slicing - Fixed Abrasive Slicing Technique. Phase 3 Silicon Sheet Growth Development for the Large Area Sheet Task of the Low-cost Solar Array Project

    Science.gov (United States)

    Schmid, F.; Khattak, C. P.

    1979-01-01

    Several 20 cm diameter silicon ingots, up to 6.3 kg. were cast with good crystallinity. The graphite heat zone can be purified by heating it to high temperatures in vacuum. This is important in reducing costs and purification of large parts. Electroplated wires with 45 um synthetic diamonds and 30 um natural diamonds showed good cutting efficiency and lifetime. During slicing of a 10 cm x 10 cm workpiece, jerky motion occurred in the feed and rocking mechanisms. This problem is corrected and modifications were made to reduce the weight of the bladeheat by 50%.

  5. Radiofrequency plasma heating: proceedings

    International Nuclear Information System (INIS)

    The conference proceedings include sessions on Alfven Wave Heating, ICRF Heating and Current Drive, Lower Hybrid Heating and Current Drive, and ECRF Heating. Questions of confinement, diagnostics, instabilities and technology are considered. Individual papers are cataloged separately

  6. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  7. Heat-Related Illnesses

    Science.gov (United States)

    ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  8. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  9. Low temperature nuclear heat

    Energy Technology Data Exchange (ETDEWEB)

    Kotakorpi, J.; Tarjanne, R. (comps.)

    1977-08-01

    The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

  10. High thermal power density heat transfer apparatus providing electrical isolation at high temperature using heat pipes

    Science.gov (United States)

    Morris, J. F. (Inventor)

    1985-01-01

    This invention is directed to transferring heat from an extremely high temperature source to an electrically isolated lower temperature receiver. The invention is particularly concerned with supplying thermal power to a thermionic converter from a nuclear reactor with electric isolation. Heat from a high temperature heat pipe is transferred through a vacuum or a gap filled with electrically nonconducting gas to a cooler heat pipe. If the receiver requires gratr thermal power density, geometries are used with larger heat pipe areas for transmitting and receiving energy than the area for conducting the heat to the thermionic converter. In this way the heat pipe capability for increasing thermal power densities compensates for the comparative low thermal power densities through the electrically nonconducting gap between the two heat pipes.

  11. 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.

  12. Research on Combined Application Technology of Solar and Ground Source Heat Pump in Severe Cold Area based on TRNSYS%基于TRNSYS的严寒地区太阳能和地源热泵联合应用技术研究

    Institute of Scientific and Technical Information of China (English)

    潘建伍

    2013-01-01

    Based on TRNSYS software numerical simulation, research on the technical feasibility and the parameter optimization of combined application technology of solar energy and ground source heat pump in severe cold area were carried out. The results showed combined application technology of solar energy and ground source heat pump in severe cold area is feasible. Parallel source-side complement heating mode has relatively high efficiency, so flat plate collector was recommended. COP of the source side thermal complement parallel system increases non-linearly with the collector area, but it stabilizes when reaching a certain value.%基于对TRNSYS软件进行数值模拟,在严寒地区对太阳能和地源热泵联合应用技术的可行性和参数优选等问题进行研究.结果表明,在严寒地区采用太阳能和地源热泵联合供热采暖系统是可行的,采用并联型源侧补热模式的效率相对较高,建议选用平板式集热器,并联型源侧补热系统的全年COP随集热器面积的增大,非线性提高到一定值之后,COP趋于稳定.

  13. Solar dynamic space power system heat rejection

    Science.gov (United States)

    Carlson, A. W.; Gustafson, E.; Mclallin, K. L.

    1986-01-01

    A radiator system concept is described that meets the heat rejection requirements of the NASA Space Station solar dynamic power modules. The heat pipe radiator is a high-reliability, high-performance approach that is capable of erection in space and is maintainable on orbit. Results are present of trade studies that compare the radiator system area and weight estimates for candidate advanced high performance heat pipes. The results indicate the advantages of the dual-slot heat pipe radiator for high temperature applications as well as its weight-reduction potential over the range of temperatures to be encountered in the solar dynamic heat rejection systems.

  14. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  15. Modelling the Heat Consumption in District Heating Systems using a Grey-box approach

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Madsen, Henrik

    2006-01-01

    The heat consumption in a large geographical area is considered together with climate measurements on a single location in the area. The purpose is to identify a model linking the heat consumption to climate and calendar information. The process of building a model is split into a theoretical bas......-box approach. (c) 2005 Elsevier B.V. All rights reserved....

  16. HEAT TRANSFER ENHANCEMENT OF SMALL SCALE HEAT SINKS USING VIBRATING PIN FIN

    Directory of Open Access Journals (Sweden)

    Suabsakul Gururatana

    2013-01-01

    Full Text Available Heat sinks are widely adopted in electronics cooling together with different technologies to enhance the cooling process. For the small electronics application, the small scale pin fins heat sinks are extensively used to dissipate heat in electronics devices. Due to the limit of space in the small devices, it is impossible to increase heat transfer area. In order to improve the heat transfer performance, the applying the forced vibration is one of challenging method. This study applies the vibration frequency between 50 to 1,000 Hz to pin fins heat sinks. The results of numerical simulation clearly show satisfied heat transfer augmentation. However, the Pressure drop significantly increases with frequency. This phenomenon affects the heat transfer enhancement performance that it increases with frequency until certain value then it drops rapidly. The results of this study can help designing heat sinks for electronics cooling by employing the concept of vibration.

  17. Toward a Heat Recovery Chimney

    Directory of Open Access Journals (Sweden)

    Min Pan

    2011-11-01

    Full Text Available The worldwide population increase and subsequent surge in energy demand leads electricity producers to increase supply in an attempt to generate larger profit margins. However, with Global Climate Change becoming a greater focus in engineering, it is critical for energy to be converted in as environmentally benign a way as possible. There are different sustainable methods to meet the energy demand. However, the focus of this research is in the area of Waste Heat Recovery. The waste heat stored in the exiting condenser cooling water is delivered to the air flow through a water-air cross flow heat exchanger. A converging thermal chimney structure is then applied to increase the velocity of the airflow. The accelerated air can be used to turn on the turbine-generator installed on the top the thermal chimney so that electricity can be generated. This system is effective in generating electricity from otherwise wasted heat.

  18. Silicon Ingot Casting - Heat Exchanger Method (HEM). Multi-Wire Slicing - Fixed Abrasive Slicing Technique (Fast). Phase 4 Silicon Sheet Growth Development for the Large Area Sheet Task of the Low-Cost Solar Array Project

    Science.gov (United States)

    Schmid, F.

    1981-01-01

    The crystallinity of large HEM silicon ingots as a function of heat flow conditions is investigated. A balanced heat flow at the bottom of the ingot restricts spurious nucleation to the edge of the melted-back seed in contact with the crucible. Homogeneous resistivity distribution over all the ingot has been achieved. The positioning of diamonds electroplated on wirepacks used to slice silicon crystals is considered. The electroplating of diamonds on only the cutting edge is described and the improved slicing performance of these wires evaluated. An economic analysis of value added costs of HEM ingot casting and band saw sectioning indicates the projected add on cost of HEM is well below the 1986 allocation.

  19. Modelling of Ammonia Heat Pump Desuperheaters

    DEFF Research Database (Denmark)

    Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix;

    2015-01-01

    is that the specific heat is constant throughout the temperature glide of the refrigerant in the heat exchanger. However, considering ammonia as refrigerant, the LMTD method does not give accurate results due to significant variations of the specific heat. By comparing the actual temperature profiles from a one......This paper presents a study of modelling desuperheating in ammonia heat pumps. Focus is on the temperature profile of the superheated refrigerant. Typically, the surface area of a heat exchanger is estimated using the Log Mean Temperature Difference (LMTD) method. The assumption of this method....... The area of the heat exchanger can be increased or the condensation temperature can be raised to achieve the same temperature difference for the discretized model as for the LMTD. This would affect the compressor work, hence the COP of the system. Furthermore, for higher condenser pressure, and thus higher...

  20. 高寒地区某站房太阳能-空气/水源热泵联合供暖系统研究%The Application of Solar Energy and Air/Water Source Heat Pump Combined Heating System in the Railway Station Plateau Cold Area

    Institute of Scientific and Technical Information of China (English)

    李雨潇; 冯炼; 袁艳平

    2016-01-01

    The simulated calculation model are established for the solar energy and air/water source heat pump combined heating system based on TRNSYS, which use double evaporator heat pump and set up double water tank. Makes studys on operating characteristics of the system based on typical days and single and double tanks two conditions. The results indicate that this system has high solar assurance, and the use of double tanks can be improved the total quantity of heat, especially for the immediate tank heating quantity.%利用TRNSYS软件建立了高寒地区某站房太阳能-空气/水源热泵联合供暖系统仿真模型,该系统设置双蒸发器和双水箱。通过对典型天工况和单双水箱工况下应用性能的研究,其结果表明,该系统具有较高的太阳能保证率,双水箱的使用可增加水箱的总供热量,并且对水箱直接供热量有明显提升。

  1. Nonazeotropic Heat Pump

    Science.gov (United States)

    Ealker, David H.; Deming, Glenn

    1991-01-01

    Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

  2. Simulation of induction heating process with radiative heat exchange

    Directory of Open Access Journals (Sweden)

    A. Kachel

    2007-05-01

    Full Text Available Purpose: Numerical modelling of induction heating process is a complex issue. It needs analysis of coupled electromagnetic and thermal fields. Calculation models for electromagnetic field analysis as well as thermal field analysis need simplifications. In case of thermal field calculations, correct modelling of radiative heat exchange between the heated charge and inductor’s thermal insulation is essential. Most commercial calculation programs enabling coupled analysis of electromagnetic and thermal fields do not allow taking into consideration radiative heat exchange between calculation model components, which limits thermal calculations only to the charge area. The paper presents a supplementation of the program Flux 2D with radiative heat exchange procedures.Design/methodology/approach: Commercial program Flux 2D designed for coupled electromagnetic and thermal calculation (based on finite element method was supplemented with authors program for radiative heat exchange based on numerical integration of classic equations.Findings: Supplementation EM-T calculations with radiative heat exchange between charge and inductor enables to calculate thermal insulation parameters and increase precision of modelling.Research limitations/implications: Procedures for radiative heat exchange enables calculation of two surfaces (flat or cylindrical with finite dimensions. The surfaces can be displaced relative to each other (charge shorter or longer than thermal insulation of inductor. Material of surfaces is modelled as: flat, diffuse, radiant surfaces absorb energy evenly in the whole spectrum (grey bodies. The whole system is modelled as in a steady thermal state (quasi-steady.Originality/value: Authors program extends Flux 2D features with a possibility for calculating radiative heat transfer. The application of radiative process is possible between all components of the studied model, not only for the boundary conditions.

  3. Applicability of Variational Method to Heat Flux Estimation in Semi-Arid Area of Northwest China%变分方法估算西北半干旱区地表热通量的适用性研究

    Institute of Scientific and Technical Information of China (English)

    张述文; 曹帮军

    2013-01-01

    Using the surface heat fluxes data observed by eddy covariance (EC) method,radiation observation data,three heights of wind,humidity and temperature observation data in Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) during June,July and August 2009,the fluxes estimated by variational method were compared against those observed by EC method and also the effects were investigated on estimated heat fluxes when using the different similarity functions in the variational method.The results show that the heat fluxes estimated by the variational method generally have the same temporal changes as those from EC method but difference exist during time periods around midday.The performances are different by using the different similarity functions with the variational method:In the unstable conditions,the different similarity functions has a great effect on heat flux estimation,however,the impact will significantly reduce when the unstable condition become weak; under the stable conditions,the effect is very small on heat flux estimation by using the different similarity functions so it could be ignored as compared with the observational errors.%利用2009年6-8月兰州大学半干旱气候与环境观测站(SACOL)的地表辐射观测资料,近地层大气温度、湿度和水平风速的三层梯度观测资料,以及热通量的涡动相关观测,比较了变分法估算的地表热通量与涡动相关观测值间差异,评估了不同相似函数对变分法估算地表热通量的影响.结果表明,变分法估算的地表热通量在时间变化趋势上与涡动相关观测值一致,但在中午前后时段还存在数值大小差异.不同相似函数对变分法估算热通量的影响不一样:当层结不稳定时,其对热通量估算的影响较大;当层结不稳定变弱时,影响会显著变小;当层结稳定时,影响非常小,与观测误差相比可以忽略.

  4. Experimental Study of Heat Transfer of Boreholes in Closed Loop Vertical Ground Heat Exchangers in a Cold Winter and Hot Summer Area%两种土壤热物性测试方法试验研究及影响因素分析

    Institute of Scientific and Technical Information of China (English)

    郑晓红; 任倩; 钱华

    2011-01-01

    地源热泵空调系统目前在国内已得到广泛使用,而地埋管周围岩土体的热物性的获取对于其系统设计及研究至关重要.本文通过对近水源和较远水源的测试井进行实地测试,对比了应用热响应原理的岩土体热物性的测定方法与直接测试法所得出的土壤导热系数和热扩散率,结果表明热响应原理测试计算所得的热物性具有较高的准确性.%As a renewable energy technology for space heating and cooling, ground source heat pump ( GSHP) systems have been encouraged to be used by China government. In Jiangsu Province, located at the East China, the zone with hot summer and cold winter, the number of closed loop vertical ground source heat pump systems is increasing rapidly in recent years. Accurate soil property is helpful for properly using ground source heat pump. This paper reported the preliminary results investigate the soil parameters and the potential to use ground heat source pump for a stage of long term project. Thermal response and measured soil samples from borehole were used to measure the conductivity of soil and results are compared. Results show that thermal response measured synthetic soil conductivity is higher than that measured samples directly. And the borehole close to river has higher water content and higher synthetic conductivity which is due to the enhancement of heat transfer by slowly water flow.

  5. Electric heating provides a high level of home comfort - economically

    Energy Technology Data Exchange (ETDEWEB)

    Haapakoski, M.

    1997-11-01

    Research and development at IVO in the area of electric heating boasts a tradition going back almost thirty years. Research aimed at further progress is continuing. IVO and power companies launched the `Electrically heated houses of the century` project four years ago. The first results show that electric heating continues to be very competitive with other heating systems. It is an economical way of heating the home and it also increases the comfort of those living there

  6. Heat transfer between graphene and amorphous SiO2.

    Science.gov (United States)

    Persson, B N J; Ueba, H

    2010-11-24

    We study the heat transfer between graphene and amorphous SiO(2). We include both the heat transfer from the area of real contact, and between the surfaces in the non-contact region. We consider the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies, and the heat transfer by the gas in the non-contact region. We find that the dominant contribution to the heat transfer results from the area of real contact, and the calculated value of the heat transfer coefficient is in good agreement with the value deduced from experimental data.

  7. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  8. Heat pump technology

    CERN Document Server

    Von Cube, Hans Ludwig; Goodall, E G A

    2013-01-01

    Heat Pump Technology discusses the history, underlying concepts, usage, and advancements in the use of heat pumps. The book covers topics such as the applications and types of heat pumps; thermodynamic principles involved in heat pumps such as internal energy, enthalpy, and exergy; and natural heat sources and energy storage. Also discussed are topics such as the importance of the heat pump in the energy industry; heat pump designs and systems; the development of heat pumps over time; and examples of practical everyday uses of heat pumps. The text is recommended for those who would like to kno

  9. Aerodynamic heating of ballistic missile including the effects of gravity

    Indian Academy of Sciences (India)

    S N Maitra

    2000-10-01

    The aerodynamic heating of a ballistic missile due to only convection is analysed taking into consideration the effects of gravity. The amount of heat transferred to the wetted area and to the nose region has been separately determined, unlike A Miele's treatise without consideration of gravity. The peak heating ratesto the wetted area and to the nose of the missile are also investigated. Finally four numerical examples are cited to estimate the errors, in heat transfers and heating ratesto both wetted area and nose region of the missile, arising out of neglecting the gravitational forces.

  10. Experimental Investigations of Vertical and Horizontal Heat Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Guk; Kim, Kyuung Mo; Jeong, Young Shin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The interest in the application of heat pipes for heat transfer system is well known in industrial fields. Heat pipe uses the working fluid in containment as cylindrical shape tube. Vaporization occurs in evaporation section due to the heat input and vapor is transferred to condensation section. At the condensation area, the working fluid is condensed and immersed in the wick structure, which has highly porous media. The condensed working fluid returns to evaporator section by capillary wicking of wick structure. The driving force for working fluid is affected by capillary and gravitational force. The heat pipes for nuclear systems have been suggested as horizontal loop heat pipes for reactor core cooling system or vertical heat pipes for passive cooling for spent fuel. In the present research, preliminary tests of horizontal and vertical heat pipe were studied for its heat transfer performance. The main purpose of the research was the analysis of heat transfer behavior of heat pipe and the performance of heat transfer. The thermal performances of horizontal and vertical heat pipe were measured experimentally. Vertical heat pipe showed better performance compared to horizontal one, at high heat input region. The heat transfer coefficients of horizontal heat pipe were lower than vertical one because of gravitational force. Overall heat transfer coefficient of vertical heat pipes were enhanced to 28.5 % compared to the horizontal heat pipes. The horizontal heat pipes revealed high thermal resistance up to 54.3 % compared to vertical heat pipes. Therefore, vertical heat pipes analyzed better heat transfer performance than horizontal heat pipe.

  11. Experimental Investigations of Vertical and Horizontal Heat Pipes

    International Nuclear Information System (INIS)

    The interest in the application of heat pipes for heat transfer system is well known in industrial fields. Heat pipe uses the working fluid in containment as cylindrical shape tube. Vaporization occurs in evaporation section due to the heat input and vapor is transferred to condensation section. At the condensation area, the working fluid is condensed and immersed in the wick structure, which has highly porous media. The condensed working fluid returns to evaporator section by capillary wicking of wick structure. The driving force for working fluid is affected by capillary and gravitational force. The heat pipes for nuclear systems have been suggested as horizontal loop heat pipes for reactor core cooling system or vertical heat pipes for passive cooling for spent fuel. In the present research, preliminary tests of horizontal and vertical heat pipe were studied for its heat transfer performance. The main purpose of the research was the analysis of heat transfer behavior of heat pipe and the performance of heat transfer. The thermal performances of horizontal and vertical heat pipe were measured experimentally. Vertical heat pipe showed better performance compared to horizontal one, at high heat input region. The heat transfer coefficients of horizontal heat pipe were lower than vertical one because of gravitational force. Overall heat transfer coefficient of vertical heat pipes were enhanced to 28.5 % compared to the horizontal heat pipes. The horizontal heat pipes revealed high thermal resistance up to 54.3 % compared to vertical heat pipes. Therefore, vertical heat pipes analyzed better heat transfer performance than horizontal heat pipe

  12. Students' Misconceptions about Heat Transfer Mechanisms and Elementary Kinetic Theory

    Science.gov (United States)

    Pathare, S. R.; Pradhan, H. C.

    2010-01-01

    Heat and thermodynamics is a conceptually rich area of undergraduate physics. In the Indian context in particular there has been little work done in this area from the point of view of misconceptions. This prompted us to undertake a study in this area. We present a study of students' misconceptions about heat transfer mechanisms, i.e. conduction,…

  13. Heat Rash or Prickly Heat (Miliaria Rubra)

    Science.gov (United States)

    ... heat rash consist of controlling heat and humidity. Acetaminophen or ibuprofen can help to reduce fever. Remove ... without any sweat. Your child may complain of dizziness, nausea, weakness, headache, confusion, or difficulty breathing. This ...

  14. Solar Heating System at a Racquetball Club

    Science.gov (United States)

    1982-01-01

    Detailed 93-page report describes Arlington, Virginia racquetball club which obtains heat and hot water for its support area from solar collectors. Report explains modes of operation of system and details of acceptance-test plan.

  15. Assessing Heat Health Risk for Sustainability in Beijing’s Urban Heat Island

    Directory of Open Access Journals (Sweden)

    Weihua Dong

    2014-10-01

    Full Text Available This research is motivated by the increasing threat of urban heat waves that are likely worsened by pervasive global warming and urbanization. Different regions of the city including urban, borderland and rural area will experience different levels of heat health risk. In this paper, we propose an improved approach to quantitatively assess Beijing’s heat health risk based on three factors from hazard, vulnerability and especially environment which is considered as an independent factor because different land use/cover types have different influence on ambient air temperatures under the Urban Heat Island effect. The results show that the heat health risk of Beijing demonstrates a spatial-temporal pattern with higher risk in the urban area, lower risk in the borderland between urban and rural area, and lowest risk in the rural area, and the total risk fluctuated dramatically during 2008–2011. To be more specific, the heat health risk was clearly higher in 2009 and 2010 than in 2008 and 2011. Further analysis with the urban area at sub-district level signifies that the impervious surface (urban area such as buildings, roads, et al. ratio is of high correlation with the heat health risk. The validation results show that the proposed method improved the accuracy of heat health risk assessment. We recommend that policy makers should develop efficient urban planning to accomplish Beijing’s sustainable development.

  16. Heat Flow Pattern and Thermal Resistance Modeling of Anisotropic Heat Spreaders

    Science.gov (United States)

    Falakzaadeh, F.; Mehryar, R.

    2016-08-01

    To ensure safe operating temperatures of the ever smaller heat generating electronic devices, drastic measures should be taken. Heat spreaders are used to increase surface area, by spreading the heat without necessarily transferring it to the ambient in the first place. The heat flow pattern is investigated in heat spreaders and the fundamental differences regarding how heat conducts in different materials is addressed. Isotropic materials are compared with anisotropic ones having a specifically higher in-plane thermal conductivity than through plane direction. Thermal resistance models are proposed for anisotropic and isotropic heat spreaders in compliance with the order of magnitude of dimensions used in electronics packaging. After establishing thermal resistance models for both the isotropic and anisotropic cases, numerical results are used to find a correlation for predicting thermal resistance in anisotropic heat spreaders with high anisotropy ratios.

  17. Heat exchangers for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rabghi, O.M.; Akyurt, M.; Najjar, Y.S.H.; Alp, T. (King Abdulaziz Univ., Jeddah (Saudi Arabia). College of Engineering)

    1993-01-01

    A survey is made of the equipment used for heat recovery and utilization. Types and merits of commonly employed heat exchangers are presented, and criteria for selecting heat exchangers are summarized. Applications for waste heat recovery are emphasized. It is concluded that careful selection and operation of such equipment would be expected to result in energy savings as well as problem-free operation. (author)

  18. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  19. Heat Cramps, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Cramps, First Aid A A A Heat cramp signs and symptoms ... if later stages of heat illness are suspected. First Aid Guide Use a combination of the following measures, ...

  20. Heat Exhaustion, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Exhaustion, First Aid A A A Heat exhaustion signs and symptoms ... specific to the other stages of heat illness. First Aid Guide Use a combination of the following measures ...

  1. Heat Roadmap Europe 1

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg;

    2012-01-01

    Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

  2. Energy efficient ammonia heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)

    2013-09-15

    The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

  3. Regenerative adsorbent heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  4. Agricultural and industrial process heat

    Science.gov (United States)

    Dollard, J.

    1978-01-01

    The application of solar energy to agricultural and industrial process heat requirements is discussed. This energy end use sector has been the largest and it appears that solar energy can, when fully developed and commercialized, displace from three to eight or more quads of oil and natural gas in U.S. industry. This potential for fossil fuel displacement in the agricultural and industrial process heat area sector represents a possible savings of 1.4 to 3.8 million barrels of oil daily.

  5. 郑州市地下水源热泵适宜区浅层地热能资源量评价%The Shallow Geothermal Energy Resource Evaluation on the Suitable Area of Groundwater Source Heat Pump in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    田良河; 闫震鹏; 刘新号

    2011-01-01

    By numerical simulation, we determine the best distance between wells of the groundwater source heat pump in Zhengzhou City, and evaluate the shallow geothermal energy resource in the suitable areas. It can provide important basis for urban development and utilization of shallow geothermal energy in Zhengzhou City.%采用数值模拟法确定了郑州市地下水源热泵适宜区最佳井间距,评价了郑州市地下水源热泵适宜区浅层地热能资源。

  6. 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)

  7. Experimental investigation of a reticulated porous alumina heat exchanger for high temperature gas heat recovery

    International Nuclear Information System (INIS)

    The present study presents an experimental study of a prototype counter-flow heat exchanger designed to recover sensible heat from inert and reactive gases flowing through a high temperature solar reactor for splitting CO2. The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pores per inch (ppi). The RPC provides high heat transfer surface area per unit volume (917 m−1) with low pressure drop. Measurements include the permeability, inertial coefficient, overall heat transfer coefficient, effectiveness and pressure drop. For laminar flow and an inlet gas temperature of 1240 K, the overall heat transfer coefficients are 36–41 W m−2 K−1. The measured performance is in good agreement with a prior CFD model of the heat exchanger. - Highlights: • A ceramic heat exchanger provides gas-phase heat recuperation for a solar thermochemical reactor. • Alumina reticulated porous ceramic (RPC) provides high surface area and low pressure drop. • Heat transfer and pressure drop are measured at temperatures up to 1240 K. • RPC provides a 9-fold increase in heat transfer compared to bare tubes

  8. Economics of installation of solar heating plants

    Science.gov (United States)

    Popel, O. S.; Frid, S. Y.; Shpiltayn, E. E.

    1984-04-01

    An engineering-economic analysis of solar heating plants for determination of their cost effectiveness involves calculating the maximum economically feasibile extra capital investment on their installation and calculating the fraction of the total heat demand covered by such a plant which makes replacement of conventional heating plant maximally economical. The annual economic effect of solar heating is calculated in terms of normalized cost differential, as criterion for its competitiveness with conventional heating. Plant performance characteristics, namely dependence of both the percent demand coverage and the annual cost differential on the area of solar radiation collectors is then considered. Analysis of the cost equation, assuming that the extra fixed cost is proportional to the collector area, reveals the necessary and sufficient condition for decrease of annual operating cost.

  9. Competition in the household heat product markets in Finland

    International Nuclear Information System (INIS)

    In the article the market of household heat products is defined independently. The market consists mainly of electricity, district heating, light fuel oil, and wood. Geographically household heat product markets are limited to the area which is covered by the local district heating network. We test indirectly whether this market definition is valid, i.e. do different household heat products act as substitutes to each other. However, the substitution may quite often be limited since the local district heat supplier is the only supplier on the area and also electricity companies have high market shares in the area they are located. The amount of competitors even in these enlarged markets is low. Also the local district heating network gives a technological potential to non-competitive product specific pricing. Thus, a relevant case exists where the district heating company can determine the price of its product without constraints from other firms and heat products. We test empirically whether the local prices of district heating are affected by the local heat product market shares of district heating companies. We use panel data which consists of 75 district heating companies in years 1996 - 2002. The data includes market share, joint production, district heating tariffs, production scale, and raw material input cost variables. The results obtained from different estimations indicate clearly that competitive case is not the prevailing one in the Finnish district heating pricing. The market shares of district heating companies had a positive effect on the district heating prices. The result also does not support the hypothesis that different household heat products belong to same heat product markets. (Author)

  10. Analysis of Causes of Karst Collapse and the Corresponding Countermeasures During the Running of Ground Source Heat Pump in the Covered Karst Areas%覆盖型岩溶区地下水地源热泵工程岩溶塌陷成因及对策研究

    Institute of Scientific and Technical Information of China (English)

    段启杉; 曹振东; 孟凡涛; 宋小庆

    2015-01-01

    地下水地源热泵工程是抽取地下水,以地下水为换热介质,提取能量之后全部回灌于含水层中。因此地下水地源热泵是改变地下水局部水位高程,整体上不影响地下水流场的变化。覆盖型岩溶区地质环境承载力较差,地下水的开发利用过程,可能加强诱发岩溶塌陷的因素,发生岩溶塌陷。在地下水地源热泵的建设和运行中,控制水位降深、尽量避免水位波动和瞬间水位变化过大等措施,达到预防岩溶塌陷的目的。而岩溶塌陷预防措施的研究给覆盖型岩溶区地下水地源热泵的建设和运行提供技术支撑。%Ground source heat pump engineering is pumping groundwater, groundwater as heat transfer medium, extract the energy after full recharge in the aquifer. So the groundwater source heat pump is to change the local groundwater level elevation, on the whole does not affect the change of the groundwater flow field. Covered karst area with poor bearing capacity of geological envi-ronment, the development and utilization of groundwater, karst collapse could strengthen induced factors, karst collapse occurred. In groundwater in the construction and operation of ground source heat pump, control the water level drawdown, avoid water level fluctuation and instantaneous water level change is too big, so as to achieve the purpose of prevention of karst collapse, and preven-tive measures of karst collapse research covered karst area groundwater source heat pump with pumping and technical support for the construction and operation.

  11. The urban heat island dynamics during heat waves: a study of cities in the United States

    Science.gov (United States)

    Hu, Leiqiu

    2016-04-01

    The urban heat island (UHI) is a common phenomenon describing that metropolitan areas are usually warmer than their rural surroundings. This effect is compounded by extreme heat events, which are a leading cause of weather-related human mortality in many countries worldwide. However, the spatial and diurnal variability of temperature and humidity in urban and adjacent rural areas during extreme heat events is not well measured and therefore not well understood. The recently developed dataset of near-surface air and dew temperature from MODIS atmospheric profiles and the new method for the UHI quantification--urban heat island curve are used to quantify the urban climatic changes during heat waves in cities of the United States. The enhanced and weakened UHIs are observed in various cities. The causes of UHI changes during heat waves are discussed, including climate region, vegetation type and amount, city geolocation, etc.

  12. Rankine cycle waste heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Nelson, Christopher R.

    2015-09-22

    A waste heat recovery (WHR) system connects a working fluid to fluid passages formed in an engine block and/or a cylinder head of an internal combustion engine, forming an engine heat exchanger. The fluid passages are formed near high temperature areas of the engine, subjecting the working fluid to sufficient heat energy to vaporize the working fluid while the working fluid advantageously cools the engine block and/or cylinder head, improving fuel efficiency. The location of the engine heat exchanger downstream from an EGR boiler and upstream from an exhaust heat exchanger provides an optimal position of the engine heat exchanger with respect to the thermodynamic cycle of the WHR system, giving priority to cooling of EGR gas. The configuration of valves in the WHR system provides the ability to select a plurality of parallel flow paths for optimal operation.

  13. Heat flow in northwest Pacific marginal seas

    Institute of Scientific and Technical Information of China (English)

    JIANG Lili; LI Guanbao; LI Naisheng

    2004-01-01

    Heat flow studies in Northwest Pacific marginal seas has a more than 40 years history with more than 4000 heat flow values obtained. The regional average value is 80.4 mW/m2, which is lower than the world's 87 mW/m2, but higher than those of the Eurasia continent and the Pacific Ocean. This reflects the regional crust property in the area. The studies on distribution of the heat flow and contour pattern of heat flow in 1°×1°and 2°×2°scales in Northwest Pacific marginal seas revealed that the most high heat flow anomalies in the area were found along back-arc basins and island arc in an obviously northeasterly track. Exceptions are the Komandoskaya Basin (KMB), the Izu-Bonin Trough (IBT) and the Mariana Trough (MT), which extend in northwest. The contours of low heat flow marked the boundaries of the continent and the ocean. The present heat flow values reflect the imprint of the last thermal event and relate closely to tectonic activity. The high heat flow gradient areas have high frequency of earthquake. Therefore, the area of faulting controlled the pattern of the heat flow anomalies. Heat flow gradient in 135°direction indicated a major lithosphere transformation oceanward resulting from movement of the earth's material. In this paper, we described patterns of heat flow distribution in the Northwest Pacific, heat flow value changes in horizontal and vertical directions, combining the studies of Shi (1997) on the landforms of the island arcs in east Asia and plate movement, and the results of Shi and Zhang (1998) on heat simulation of subduction of active ocean mountain and the activity of islands arc. A preliminary model of geodynamics in the Northwest Pacific and its adjacent area was put forward. There is a great lateral heat flow gradient on the surface of the mantle between ocean and continent, which indicates that the materials in asthenosphere move from continent to ocean causing movement of the crust.

  14. Investigations of Intelligent Solar Heating Systems for Single Family House

    DEFF Research Database (Denmark)

    Andersen, Elsa; Chen, Ziqian; Fan, Jianhua;

    2014-01-01

    is a tank in tank heat storage with domestic hot water in the inner tank and space heating water in the outer tank. The total tank volume is 750 liters and the solar collector area is 9 m2. The auxiliary energy supply system is based on electrical heating element(s)/heat pump and is different for all three......Three differently designed intelligent solar heating systems are investigated experimentally in a test facility. The systems provide all the needed yearly heating demand in single family houses. The systems are based on highly stratified tanks with variable auxiliary heated volumes. The tank...... systems.The system will be equipped with an intelligent control system where the control of the electrical heating element(s)/heat pump is based on forecasts of the variable electricity price, the heating demand and the solar energy production.By means of numerical models of the systems made in Trnsys...

  15. Entransy dissipation analysis and optimization of separated heat pipe system

    Institute of Scientific and Technical Information of China (English)

    QIAN XiaoDong; LI Zhen; MENG JiAn; LI ZhiXin

    2012-01-01

    Seperated heat pipe systems are widely used in the fields of waste heat recovery and air conditioning due to their high heat transfer capability,and optimization of heat transfer process plays an important role in high-efficiency energy utilization and energy conservation.In this paper,the entransy dissipation analysis is conducted for the separated heat pipe system,and the result indicates that minimum thermal resistance principle is applicable to the optimization of the separated heat pipe system.Whether in the applications of waste heat recovery or air conditioning,the smaller the entransy-dissipation-based thermal resistance of the separated heat pipe system is,the better the heat transfer performance will be.Based on the minimum thermal resistance principle,the optimal area allocation relationship between evaporator and condenser is deduced,which is numerically verified in the optimation design of separated heat pipe system.

  16. Boise geothermal district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  17. Essentials of radiation heat transfer

    CERN Document Server

    Balaji

    2014-01-01

    Essentials of Radiation Heat Transfer is a textbook presenting the essential, fundamental information required to gain an understanding of radiation heat transfer and equips the reader with enough knowledge to be able to tackle more challenging problems. All concepts are reinforced by carefully chosen and fully worked examples, and exercise problems are provided at the end of every chapter. In a significant departure from other books on this subject, this book completely dispenses with the network method to solve problems of radiation heat transfer in surfaces. It instead presents the powerful radiosity-irradiation method and shows how this technique can be used to solve problems of radiation in enclosures made of one to any number of surfaces. The network method is not easily scalable. Secondly, the book introduces atmospheric radiation, which is now being considered as a potentially important area, in which engineers can contribute to the technology of remote sensing and atmospheric sciences in general, b...

  18. Perioperative thermoregulation and heat balance.

    Science.gov (United States)

    Sessler, Daniel I

    2016-06-25

    Core body temperature is normally tightly regulated to within a few tenths of a degree. The major thermoregulatory defences in humans are sweating, arteriovenous shunt vasoconstriction, and shivering. The core temperature triggering each response defines its activation threshold. General anaesthetics greatly impair thermoregulation, synchronously reducing the thresholds for vasoconstriction and shivering. Neuraxial anaesthesia also impairs central thermoregulatory control, and prevents vasoconstriction and shivering in blocked areas. Consequently, unwarmed anaesthetised patients become hypothermic, typically by 1-2°C. Hypothermia results initially from an internal redistribution of body heat from the core to the periphery, followed by heat loss exceeding metabolic heat production. Complications of perioperative hypothermia include coagulopathy and increased transfusion requirement, surgical site infection, delayed drug metabolism, prolonged recovery, shivering, and thermal discomfort. Body temperature can be reliably measured in the oesophagus, nasopharynx, mouth, and bladder. The standard-of-care is to monitor core temperature and to maintain normothermia during general and neuraxial anaesthesia. PMID:26775126

  19. Regenerative heat sources for heating networks; Regenerative Waermequellen fuer Waermenetze

    Energy Technology Data Exchange (ETDEWEB)

    Huenges, Ernst [GeoForschungsZentrum Potsdam (Germany); Sperber, Evelyn [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany); Eggers, Jan-Bleicke [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany); Noll, Florian [Institut fuer ZukunftsEnergieSysteme (IZES), Saarbruecken (Germany); Kallert, Anna Maria [Fraunhofer-Institut fuer Bauphysik, Stuttgart (Germany); Reuss, Manfred [ZAE Bayern - Bayerisches Zentrum fuer Angewandte Energieforschung e.V., Wuerzburg (Germany)

    2015-04-15

    The ambitious goal, the German Federal Government has set itself, to reduce the emissions of greenhouse gases by 80% to 95% by the year 2050. As there are currently more than half of German energy consumption for the production of heat is required, big contributions to climate protection can be expected from this area if more renewable heat sources are used. Renewable heat sources such as bioenergy, solar thermal and geothermal energy in particular can be provided as compared to fossil fuels with significantly lower specific CO{sub 2} emissions. Objectives in the heating market and scenarios for the transformation of the heat sector have been elaborated in the BMU Lead Study 2011. The main pillar of this scenario is the reduction of final energy consumption for heat by the energy-efficient renovation of existing buildings and further increasing demands on the energetic quality of new buildings. To cover the remaining energy demand, a focus is on the expansion of heating networks based on renewable energies. [German] Die Bundesregierung hat sich das ambitionierte Zielgesetzt, bis zum Jahr 2050 die Emissionen von Treib-hausgasen um 80 % bis 95 % zu senken. Da derzeit mehr als die Haelfte des deutschen Endenergieverbrauchs fuer die Erzeugung von Waerme benoetigt wird, koennen grosse Beitraege zum Klimaschutz aus diesem Bereich erwartet werden, wenn verstaerkt erneuerbare Waermequellen eingesetzt werden. Erneuerbare Waermequellen wie Bioenergie, Solarthermie und insbesondere Geothermie koennen im Vergleich zu fossilen Quellen mit signifikant niedrigeren spezifischen CO{sub 2}-Emissionen bereitgestellt werden. Ziele im Waermemarkt und Szenarien zur Transformation des Waermesektors wurden in der BMU-Leitstudie 2011 ausgearbeitet. Tragende Saeule dieses Szenarios ist die Reduktion des Endenergieverbrauchs fuer Waerme durch die energetische Sanierung des Gebaeudebestandes und weiter ansteigenden Anforderungen an die energetische Qualitaet von Neubauten. Zur Deckung des

  20. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  1. The Gravitational Heat Exchanger

    OpenAIRE

    De Aquino, Fran

    2015-01-01

    The heat exchangers are present in many sectors of the economy. They are widely used in Refrigerators, Air-conditioners, Engines, Refineries, etc. Here we show a heat exchanger that works based on the gravity control. This type of heat exchanger can be much more economic than the conventional heat exchangers.

  2. Nature's Heat Exchangers.

    Science.gov (United States)

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  3. Compact cryocooler heat exchangers

    International Nuclear Information System (INIS)

    Compact heat exchangers are subject to different constraints as a room temperature gas is cooled down by a cold stream returning from a JT valve (or a similar cryoprocess component). In particular, the optimization of exchangers for liquid helium systems has to cover a wide range in temperature and density of the fluid. In the present work we address the following thermodynamic questions: 1. The optimization of intermediate temperatures which optimize stage operation (a stage is assumed to have a constant cross section); 2. The optimum temperature difference available for best overall economic performance values. The results are viewed in the context of porous media concepts applied to rather low speeds of fluid flow in narrow passages. In this paper examples of fluid/solid constraints imposed in this non-classical low temperature area are presented

  4. Heat flux solarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Sartarelli, A.; Vera, S.; Cyrulies, E. [Instituto de Desarrollo Humano, Univ. Nac. de Gral. Sarmiento (IDH, UNGS), Los Polvorines (Argentina); Echarri, R. [Instituto de Desarrollo Humano, Univ. Nac. de Gral. Sarmiento (IDH, UNGS), Los Polvorines (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Samson, I. [INTEC (Instituto Tecnologico Santo Domingo), Santo Domingo (Dominican Republic)

    2010-12-15

    The solarimeter presented in this work is easy to assemble. It is calibrated and its performance is validated by means of Hottel's method. Finally, the curves obtained with this solarimeter are compared to the ones obtained with a commercial solarimeter. This device is based on the evaluation of the heat flow in a metal rod. In consequence, measurements are not affected by ambient temperature variations. On the other hand, there is a linear relationship between the temperatures measured at the rod ends and the incident radiation, as can be concluded both from the theory of its operation and the calibration lines obtained. The results obtained from the global irradiance measurements in the area of Los Polvorines (Buenos Aires Province), together with a preliminary evaluation of the solarimeter's response time, are presented in this work. (author)

  5. Heat Pipe Planets

    Science.gov (United States)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  6. Molecular genetics of heat tolerance and heat shock proteins in cereals.

    Science.gov (United States)

    Maestri, Elena; Klueva, Natalya; Perrotta, Carla; Gulli, Mariolina; Nguyen, Henry T; Marmiroli, Nelson

    2002-01-01

    Heat stress is common in most cereal-growing areas of the world. In this paper, we summarize the current knowledge on the molecular and genetic basis of thermotolerance in vegetative and reproductive tissues of cereals. Significance of heat stress response and expression of heat shock proteins (HSPs) in thermotolerance of cereal yield and quality is discussed. Major avenues for increasing thermotolerance in cereals via conventional breeding or genetic modification are outlined. PMID:11999842

  7. Using a Cold Radiometer to Measure Heat Loads and Survey Heat Leaks

    Science.gov (United States)

    Dipirro, M.; Tuttle, J.; Hait, T.; Shirron, P.

    2014-01-01

    We have developed an inexpensive cold radiometer for use in thermal/vacuum chambers to measure heat loads, characterize emissivity and specularity of surfaces and to survey areas to evaluate stray heat loads. We report here the results of two such tests for the James Webb Space Telescope to measure heat loads and effective emissivities of 2 major pieces of optical ground support equipment that will be used in upcoming thermal vacuum testing of the Telescope.

  8. Application of customized absorption heat pumps for utilization of low-grade heat sources

    International Nuclear Information System (INIS)

    Based on established and proven technology of water/lithium bromide absorption chillers, customized single-stage and double-stage heat pump cycles adapted to specific applications can be designed, especially aiming at medium and large heating capacities of 500 kW and above. These heat pumps can either be fossil fired or driven by heat from combined heating and power (CHP) systems or other sources. In terms of primary energy saving, in many cases this is the most suitable technology to utilize the available heat sources. This is demonstrated by three examples of current installations in southern Germany. An analysis of the energetic performance and of the economic situation has been performed. At a municipal composting plant, waste heat is generated at a temperature level of about 40-50 deg. C. Previously, this waste heat had to be rejected to the ambient by means of a cooling tower. A direct-fired single-stage absorption heat pump has been installed which lifts the waste heat to a temperature level of 82 deg. C enabling its utilization in the local heating network of a commercial area. At a spa with various swimming pools located next to a thermal spring, a CHP engine plant is installed. The reject heat of the gas engine drives a novel two-stage absorption heat pump that utilizes the spring water as renewable heat source to provide heating of the pools and the building. In Munich, a solar-assisted local district heating system is installed in a new housing development area with about 300 accommodation units. At this site, a seasonal hot water storage for the solar system of about 5700 m3 is erected. At the beginning of the heating season, it serves the local heating network directly and afterwards - at a lower temperature level - it is utilized as heat source for an absorption heat pump that is driven by the municipal district heating network. By that concept two effects are accomplished: the available temperature change of the hot water storage is increased and

  9. Droplet Evaporator For High-Capacity Heat Transfer

    Science.gov (United States)

    Valenzuela, Javier A.

    1993-01-01

    Proposed heat-exchange scheme boosts heat transfer per unit area. Key component is generator that fires uniform size droplets of subcooled liquid at hot plate. On impact, droplets spread out and evaporate almost instantly, removing heat from plate. In practice, many generator nozzles arrayed over evaporator plate.

  10. Reliability analysis of the combined district heating systems

    Science.gov (United States)

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

    2015-12-01

    Technologies that improve the reliability and efficiency of the combined district heating systems in urban areas are considered. The calculation method of reliability of the CHP combined district heating systems is proposed. The comparative estimation of the reliability of traditional and combined district heating systems is performed.

  11. GIS based analysis of future district heating potential in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    2013-01-01

    in Denmark have been mapped in a heat atlas which includes all buildings and their heat demands. This article focuses on developing a method for assessing the costs associated with supplying these buildings with DH. The analysis is based on the existing DH areas in Denmark. By finding the heat production...

  12. Energy and exergy evaluation of an integrated solar heat pipe wall system for space heating

    Indian Academy of Sciences (India)

    ROONAK DAGHIGH; ABDELLAH SHAFIEIAN

    2016-08-01

    In this paper, an integrated solar heat pipe wall space heating system, employing double glazed heat pipe evacuated tube solar collector and forced convective heat transfer condenser, is introduced. Thermal performance of the heat pipe solar collector is studied and a numerical model is developed to investigate thethermal efficiency of the system, the inlet and outlet air temperatures and heat pipe temperature. Furthermore, the system performance is evaluated based on exergy efficiency. In order to verify the precision of the developed model, the numerical results are compared with experimental data. Parametric sensitivity for design features and material associated with the heat pipe, collector cover and insulation is evaluated to provide a combination with higher thermal performance. Simulation results show that applying a solar collector with more than 30 heat pipes is not efficient. The rate of increasing in temperature of air becomes negligible after 30 heat pipes and the trend of the thermal efficiency is descending with increasing heat pipes. The results also indicate that at a cold winter day of January, the proposed system with a 20 heat pipe collector shows maximum energy and exergy efficiency of 56.8% and 7.2%, which can afford warm air up to 30°C. At the end, the capability of the proposed system tomeet the heating demand of a building is investigated. It is concluded that the best method to reach a higher thermal covered area is to apply parallel collectors

  13. How effective is 'greening' of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the ‘urban heat island effect’? A protocol to update a systematic review

    OpenAIRE

    Knight, Teri; Price, Sian; Bowler, Diana; King, Sian

    2016-01-01

    Background: The impact of climate change on public health may occur through a number of main pathways including increased temperature, ground-level ozone levels and ultra-violet radiation, which have a range of consequences for human health. One strategy for adaptation to the predicted effects of climate change on health that has been proposed, is to ‘green’ urban areas, essentially by increasing the abundance and cover of vegetation. This protocol is for an update of a systematic review whic...

  14. Thermoelectric heat exchange element

    Science.gov (United States)

    Callas, James J.; Taher, Mahmoud A.

    2007-08-14

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  15. [Heat waves: health impacts].

    Science.gov (United States)

    Marto, Natália

    2005-01-01

    During the summer of 2003, record high temperatures were reported across Europe, causing thousands of casualties. Heat waves are sporadic recurrent events, characterised by intense and prolonged heat, associated with excess mortality and morbidity. The most frequent cause of death directly attributable to heat is heat stroke but heat waves are known to cause increases in all-cause mortality, specially circulatory and respiratory mortality. Epidemiological studies demonstrate excess casualties cluster in specific risk groups. The elderly, those with chronic medical conditions and the socially isolated are particularly vulnerable. Air conditioning is the strongest protective factor against heat-related disorders. Heat waves cause disease indirectly, by aggravating chronic disorders, and directly, by causing heat-related illnesses (HRI). Classic HRI include skin eruptions, heat cramps, heat syncope, heat exhaustion and heat stroke. Heat stroke is a medical emergency characterised by hyperthermia and central nervous system dysfunction. Treatment includes immediate cooling and support of organ-system function. Despite aggressive treatment, heat stroke is often fatal and permanent neurological damage is frequent in those who survive. Heat related illness and death are preventable through behavioural adaptations, such as use of air conditioning and increased fluid intake. Other adaptation measures include heat emergency warning systems and intervention plans and environmental heat stress reduction. Heat related mortality is expected to rise as a consequence of the increasing proportion of elderly persons, the growing urban population, and the anticipated increase in number and intensity of heat waves associated with global warming. Improvements in surveillance and response capability may limit the adverse health conditions of future heat waves. It is crucial that health professionals are prepared to recognise, prevent and treat HRI and learn to cooperate with local health

  16. Introduction to heat transfer

    CERN Document Server

    SUNDÉN, B

    2012-01-01

    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  17. 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.

  18. Open district heating and marginal cost based heat pricing

    OpenAIRE

    Mäkelä, Henri

    2014-01-01

    Currently, an increasing usage of individual heating systems such as heat pumps and solar heat collectors, pose a challenge to the district heating market. However, individual heating technologies together with industrial processes produce excess heat, which can be utilized in district heating. The usage of excess heat can be seen as an opportuni-ty for new business strategies in district heating. The objective of this thesis was to simulate hourly district heat production in an open dist...

  19. INFLUENCE OF REFRIGERANT DISTRIBUTION ON HEAT TRANSFER IN EVAPORATORS

    Institute of Scientific and Technical Information of China (English)

    高原; 田怀璋; 曾艳; 袁秀玲

    2003-01-01

    Objective To prevent the maldistribution of two-phase refrigerant in dry expansion evaporators composed of parallel coils, a distributor is needed to supply refrigerant into the coils. Methods A simplified model of dry expansion evaporator was proposed. The flow and heat transfer in distributing pipes and evaporator coils were simulated with a numerical method. Results The heat flow rate decreases while the refrigerant is distributed unequally to evaporator coils. Conclusion In order to maintain the heat flow rate, larger heat transfer area should be arranged to make up the effect of maldistribution. The larger the discrepancy of mass flow rate is, the more heat transfer area is needed.

  20. Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

    Energy Technology Data Exchange (ETDEWEB)

    Jarrell, Mark

    2013-09-30

    Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

  1. Experimental study on the start up performance of flat plate pulsating heat pipe

    Science.gov (United States)

    Hu, Chaofa; Jia, Li

    2011-06-01

    An experimental system of flat plate pulsating heat pipe was established and experimental research was carried out in this system to know the mechanism of heat transfer, start-up and operating characteristics. The factors, such as filling rate, heating power, heating method etc, which have great influence on the thermal performance of the plate pulsating heat pipe were discussed. The results indicate that heating power and filling rate are the important factors for the start-up of the plate pulsating heat pipe. The different start-up power is needed with different filling rate, and the start-up of the heat pipe in case of bottom heated is much easier than that of top heated. Increasing the heating power and enlarging the heating area can make the start-up easier. Heating power can also affect the start-up time of heat pipe under the condition of bottom heated, while it does not have some influence to the heat pipe of top heated. The thermal resistance of plate pulsating heat pipe is related with the heating power, and the higher the heating power is, the smaller the thermal resistance is. But the best filling rate which the heat pipe needs is different with different heating methods, and the performance of the heat pipe in the case of bottom heated is better than the others.

  2. Heating plan for Denmark. Appendices; Varmeplan Danmark. Bilagsrapport

    Energy Technology Data Exchange (ETDEWEB)

    2008-10-15

    Today, district heating supplies 46% of the Danish net heating demand. The present report analyses whether it will be feasible for Denmark to extend the share of district heating or whether other alternatives are better. The analysis relates to the government's and parliament's plans to reduce Denmark's CO{sub 2} emission in the short term as well as to transfer the energy supply to be based fully on renewable energy sources in the long term. The appendix volume contains 15 appendices: 1) Heating map; 2) The potential of a future district heating extension; 3) The characteristics of the district heat distribution system; 4) Model for the Danish district heat distribution net; 5) Heating savings through extra insulation; 6) Supply to new built-up areas with district heating; 7) Supply to new built-up areas from central heating plants; 8) The potential of using waste heat; 9) The potential of using biogas; 10) The potential of using large scale solar heat; 11) Use of local straw resources; 12) Cogeneration optimization; 13) Scenario analyses; 14) The potential of cost effective heating savings; 15) Model of heating plan for Denmark (ln)

  3. 农村民居外窗日光采暖的敏感性分析%Sensitivity Analysis of Solar Heating through the Outside Window of the Residential in Rural Areas

    Institute of Scientific and Technical Information of China (English)

    梁海东; 罗江海

    2011-01-01

    本文从建筑节能的角度论述了北方寒冷地区太阳辐射能量通过外窗玻璃对室内温度的影响,并根据一个简单的计算模型,分析了几种常用玻璃窗的建筑节能特点,计算结果表明:对于建筑外窗形式,双层玻璃窗节能效果最好,中空玻璃其次,单层玻璃最差;对于日光采暖,当地的太阳辐射强度,建筑物的朝向和光照是重要的影响因素,即太阳辐射能量是一个非常重要的敏感因素,而室外温度并不是一个敏感的因素.%From the point of energy-saving, this article discussed the influence of solar radiation energy through the outside windows of building in northern cold regions on the room temperature, and based on a simple calculation model, analyzed building energy-saving features of several commonly used windows. The results show that, for the form of windows, the double-layer windows have best energy saving effect, hollow glass followed, the single-layer glass is the worst; for solar heating, the local solar radiation intensity, building orientation and lighting are important factors, namely the solar radiation energy is a very important sensitive factor, while the outdoor temperature is not a sensitive factor.

  4. Challenges in Smart Low-Temperature District Heating Development

    OpenAIRE

    LI, Hongwei; Wang, Stephen Jia

    2014-01-01

    Previous research and development shows that low temperature district heating (LTDH) system is economic feasible for low energy buildings and buildings at sparse areas. Coupling with reduced network temperature and well-designed district heating (DH) networks, LTDH can reduce network heat loss by upto 75% comparing with the current medium temperature district heating system. Further system efficiency improvement can be achieved through a holistic approach which includes measures such as reduc...

  5. Revitalization Areas

    Data.gov (United States)

    Department of Housing and Urban Development — Revitalization areas are HUD-designated neighborhoods in need of economic and community development and where there is already a strong commitment by the local...

  6. MODELING OF THE HEAT PUMP STATION ADJUSTABLE LOOP OF AN INTERMEDIATE HEAT-TRANSFER AGENT (Part I

    Directory of Open Access Journals (Sweden)

    Sit B.

    2009-08-01

    Full Text Available There are examined equations of dynamics and statics of an adjustable intermediate loop of heat pump carbon dioxide station in this paper. Heat pump station is a part of the combined heat supply system. Control of transferred thermal capacity from the source of low potential heat source is realized by means of changing the speed of circulation of a liquid in the loop and changing the area of a heat-transmitting surface, both in the evaporator, and in the intermediate heat exchanger depending on the operating parameter, for example, external air temperature and wind speed.

  7. Basic heat transfer

    CERN Document Server

    Bacon, D H

    2013-01-01

    Basic Heat Transfer aims to help readers use a computer to solve heat transfer problems and to promote greater understanding by changing data values and observing the effects, which are necessary in design and optimization calculations.The book is concerned with applications including insulation and heating in buildings and pipes, temperature distributions in solids for steady state and transient conditions, the determination of surface heat transfer coefficients for convection in various situations, radiation heat transfer in grey body problems, the use of finned surfaces, and simple heat exc

  8. Microscale Regenerative Heat Exchanger

    Science.gov (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  9. Plasma heat pump and heat engine

    International Nuclear Information System (INIS)

    A model system where cold charged particles are locally confined in a volume VP within a warm plasma of volume V (VPE. The law of thermodynamics involving PE and an equation of state for PE are obtained. It is shown that the expansion/compression of electrostatic fields associated with charged particles is a new mechanism that converts mechanical work into plasma heat and vice versa. Two applications of this theory are, first we propose a pumping device which heats plasmas by an adiabatic/isothermal compression of fields. Heating power ranging from a few hundred watts to a few kilowatts is possible with the present day technology. Second, we discuss the feasibility of constructing an electrostatic heat engine which converts plasma heat into mechanical work via plasma electric fields. Effects of PE are shown to be observable in colloidal solutions.

  10. Urban Physiology: City Ants Possess High Heat Tolerance

    OpenAIRE

    Angilletta, Michael J; Wilson, Robbie S; Niehaus, Amanda C.; Michael W Sears; Navas, Carlos A.; Ribeiro, Pedro L.

    2007-01-01

    Urbanization has caused regional increases in temperature that exceed those measured on a global scale, leading to urban heat islands as much as 12 degrees C hotter than their surroundings. Optimality models predict ectotherms in urban areas should tolerate heat better and cold worse than ectotherms in rural areas. We tested these predications by measuring heat and cold tolerances of leaf-cutter ants from South America's largest city (São Paulo, Brazil). Specifically, we compared thermal tole...

  11. Long-term evolution of anthropogenic heat fluxes into a subsurface urban heat island.

    Science.gov (United States)

    Menberg, Kathrin; Blum, Philipp; Schaffitel, Axel; Bayer, Peter

    2013-09-01

    Anthropogenic alterations in urban areas influence the thermal environment causing elevated atmospheric and subsurface temperatures. The subsurface urban heat island effect is observed in several cities. Often shallow urban aquifers exist with thermal anomalies that spread laterally and vertically, resulting in the long-term accumulation of heat. In this study, we develop an analytical heat flux model to investigate possible drivers such as increased ground surface temperatures (GSTs) at artificial surfaces and heat losses from basements of buildings, sewage systems, subsurface district heating networks, and reinjection of thermal wastewater. By modeling the anthropogenic heat flux into the subsurface of the city of Karlsruhe, Germany, in 1977 and 2011, we evaluate long-term trends in the heat flux processes. It revealed that elevated GST and heat loss from basements are dominant factors in the heat anomalies. The average total urban heat flux into the shallow aquifer in Karlsruhe was found to be ∼759 ± 89 mW/m(2) in 1977 and 828 ± 143 mW/m(2) in 2011, which represents an annual energy gain of around 1.0 × 10(15) J. However, the amount of thermal energy originating from the individual heat flux processes has changed significantly over the past three decades.

  12. Theoretical and experimental studies of crossflow minichannel heat exchanger subjected to external heat ingress

    International Nuclear Information System (INIS)

    The effect of heat in-leak, an unavoidable phenomenon occurring due to the temperature difference between the system and its surroundings, has been studied for two-stream crossflow minichannel heat exchangers with unmixed fluids. Assuming that the amount of heat in-leak is known, an analytical expression for the normalised temperature difference between hot and cold fluids has been derived in terms of dimensionless parameters. The analytical results, in conjugation with the area partitioning of crossflow heat exchanger both in x and y directions, have been used for predicting the outlet fluid temperatures. On the experimental part, one of the end plates in a crossflow-type multistream, minichannel heat exchanger has been subjected to deliberate external heat input given electrically. The variation in the exit fluid temperatures has been recorded as a function of this external heat in-leak entering the exchanger through one of its outer surfaces. Experimental data obtained is employed to validate the fluid exit temperatures predicted by the developed model under the same conditions of external heat ingress. - Highlights: • Theoretical model of crossflow heat exchanger with known ambient heat leak amount. • Numerical technique of partitioning exchanger into smaller segments. • Experimental validation of model by testing of crossflow minichannel heat exchanger

  13. Enhancement of Heat Transfer Rate in Fractional Horse Power Condensing Unit

    OpenAIRE

    Tiruveedhula, Vamsi Krishna; Davuluru, Sridevi; Munnangi, Naveen

    2012-01-01

    Rating & Sizing of heat exchangers are two important challenges encountered in the system design. The rating problem is concerned with the determination total heat transfer rate, the sizing problem is concerned with the determination of the total heat transfer surface area. The key factor contributing in higher heat transfer rate & minimum heat transfer area is the air flow over the condenser coil, as the system lies in indoor of a cabinet. CFD (Computational Fluid Dynamics) is used to optimi...

  14. Heating methods and comfort; Oppvarmingsloesninger og komfort

    Energy Technology Data Exchange (ETDEWEB)

    Skree, Jostein

    2004-07-01

    Comfort is subjective. The feeling of pleasant temperature is affected by the relationship between the temperatures of the floors, walls and ceiling, and the air temperature. These temperatures should be relatively close. When energy conservation advertisements state that a room temperature of 20 - 22 degrees centigrade is enough, they refrain from making it clear that the temperature is felt differently in different situations. Different heating systems have different properties. The temperature at which the heat is transferred is also a topic. In new and energy-efficient flats it is quite common that fireplaces and stoves are little used; it is getting too hot and the temperature must be regulated by opening the windows, which results in draught problems. Some electric heaters have small surface and large airflow to the heating element. This type of heater is energy-saving because the air heats up rapidly and little heat energy is stored. But large airflow and possible dust burning are inconveniences. The most popular electric heaters, with electronic thermostat, represent a compromise between surface area, radiation heat and hot air. Comfort and selection of heating system also have something to do with the shape of the house and flat. Wood stoves and heat pumps, which deliver the heat as air, are most appropriate in houses with open spaces and small base.

  15. Radial heat flux transformer

    Science.gov (United States)

    Basiulis, A.; Buzzard, R. J.

    1971-01-01

    Unit moves heat radially from small diameter shell to larger diameter shell, or vice versa, with negligible temperature drop, making device useful wherever heating or cooling of concentrically arranged materials, substances, and structures is desired.

  16. Heat Wave Safety Checklist

    Science.gov (United States)

    ... itself. ❏ Signs of heat stroke include hot, red skin which may be dry or moist; changes in consciousness; vomiting; and high body temperature. ❏ Heat stroke is life-threatening. Call 9-1-1 or ...

  17. Device with Complex System for Heat Utilization and Reduction of Hazardous Air Emissions

    OpenAIRE

    O. Kascheeva; E. Voronov; V. Kascheev; I. Zhidovich; V. Sorokin; O. Klimenkova

    2014-01-01

    Investigations concern heat utilization and reduction of hazardous emissions occurring in residential buildings and accompanying operation of a great number of industrial enterprises in particular heat and power objects, and firstly, heat-generating units of small power located in densely populated residential areas without centralized heat supply.The investigation target is to reduce cost of heat produced by independent system of building heat supply, reduction of air pollution  due to hazar...

  18. Heat exchanger design

    OpenAIRE

    Loukota, Martin

    2014-01-01

    This bachelor thesis solves design of a heat exchanger for hot water boiler with gasification chamber for preheating the combustion air with the heat of the combustion products. Calculation values were experimentally measured. Thesis contains brief description of the shell and tube heat exchanger, stoichiometric combustion calculation, geometrical dimensions design of the heat exchanger, pressure loss and thermal performance calculation. It also includes drawings of the designed exchanger.

  19. Fabrication of Wire Mesh Heat Exchangers for Waste Heat Recovery Using Wire-Arc Spraying

    Science.gov (United States)

    Rezaey, R.; Salavati, S.; Pershin, L.; Coyle, T.; Chandra, S.; Mostaghimi, J.

    2014-04-01

    Waste heat can be recovered from hot combustion gases using water-cooled heat exchangers. Adding fins to the external surfaces of the water pipes inserted into the hot gases increases their surface area and enhances heat transfer, increasing the efficiency of heat recovery. A method of increasing the heat transfer surface area has been developed using a twin wire-arc thermal spray system to generate a dense, high-strength coating that bonds wire mesh to the outside surfaces of stainless steel pipes through which water passes. At the optimum spray distance of 150 mm, the oxide content, coating porosity, and the adhesion strength of the coating were measured to be 7%, 2%, and 24 MPa, respectively. Experiments were done in which heat exchangers were placed inside a high-temperature oven with temperature varying from 300 to 900 °C. Several different heat exchanger designs were tested to estimate the total heat transfer in each case. The efficiency of heat transfer was found to depend strongly on the quality of the bond between the wire meshes and pipes and the size of openings in the wire mesh.

  20. High heat flux loop heat pipes

    Science.gov (United States)

    North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

    1997-01-01

    Loop heat pipes (LHPs) can transport very large thermal power loads over long distances, through flexible, small diameter tubes against gravitational heads. In order to overcome the evaporator limit of LHPs, which is of about 0.07 MW/sq m, work was carried out to improve the efficiency by threefold to tenfold. The vapor passage geometry for the high heat flux conditions is shown. A bidisperse wick material within the circumferential vapor passages was used. Along with heat flux enhancement, several underlying issues were demonstrated, including the fabrication of bidisperse powder with controlled properties and the fabrication of a device geometry capable of replacing vapor passages with bidisperse powder.

  1. Liquid heat capacity lasers

    Science.gov (United States)

    Comaskey, Brian J.; Scheibner, Karl F.; Ault, Earl R.

    2007-05-01

    The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

  2. Heat roadmap China

    DEFF Research Database (Denmark)

    Xiong, Weiming; Wang, Yu; Mathiesen, Brian Vad;

    2015-01-01

    District heating is regarded as a key element of energy saving actions in the Chinese national energy strategy, while space heating in China is currently still dominated by coal boilers. However, there is no existing quantitative study to analyse the future heat strategy for China. Therefore...

  3. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Hansen, Kenneth; Connolly, David; Lund, Henrik;

    2015-01-01

    savings become more expensive than the cost of sustainable heat supply, so society does not overinvest in heat saving measures. This study first investigates the heat saving potentials for different countries in Europe, along with their associated costs, followed by a comparison with alternative ways...

  4. A hybrid solar/diesel water heating system: in medicine area in a hospital in Mexico city; Sistema hibrido de energia solar y diesel para calentamiento de agua: caso en el area de medicina fisica en un hospital en la ciudad de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Nolasco Mejia, Miguel; Wolpert Kuri, Jorge [UNAM, Mexico, D.F. (Mexico)

    2000-07-01

    A hybrid solar/diesel water heating system for therapy in a hospital in Mexico is described in this paper. The use of solar energy in hospitals and clinics, represent an environmentally friendly alternative to the burning of fossil fuels. Analysis is made regarding the feasibility of integrating both solar energy and conventional energy (fuel oil) as back up, to satisfy the hot water demand for hydrotherapy in a hospital. Results from simulation show that solar energy is a cheap means to provide up to 60% of the hot water demand. The solar assisted system proposed uses flat plate solar collectors integrated with an existing hot water tank, where water is heated with vapor from a diesel ran boiler. This represents significant savings on the solar system cost. [Spanish] La utilizacion de la energia solar en hospitales y clinicas, representa una posibilidad para obtener ahorros importantes de energia para satisfacer la demanda de agua caliente. En el presente estudio se analiza la demanda de agua caliente para uso en medicina fisica (hidroterapia), en un hospital ubicado en la Cd. De Mexico y la factibilidad de usar la energia solar, empleando como apoyo el sistema tradicional de combustible fosil (diesel). Mediante un analisis termico se determina el calor necesario para satisfacer la demanda de agua caliente. El analisis economico muestra los costos del sistema solar, los ahorros que se tendran y el periodo de recuperacion de la inversion. Los resultados muestran que la utilizacion de la energia solar es factible debido a la disminucion tanto del consumo de combustible, como de las emisiones atmosfericas. Se propone la instalacion de un sistema solar con colectores planos y el aprovechamiento de uno de los dos tanques de agua caliente existentes, donde se efectua la trasferencia de calor al agua por medio de vapor, lo cual disminuye el costo del sistema solar. La aportacion solar puede ser mayor del 60%, el complemento sera aportado por el sistema tradicional con

  5. The heat spells of Mexico City

    OpenAIRE

    Ernesto Jáuregui

    2009-01-01

    The warning of urban air has been documented to increase in intensity and area as cities grow (Oke, 1982). As the cities grow the so called heat island tends to increase the risk of more frequent heat waves as well as their impacts (IPCC, 2001). Threshold values to define a heat wave vary geographically. For the case of Mexico City located in a high inland valley in the tropics, values above 30° C (daily maximum observed for three or more consecutive days and 25° C or more as mean temperatu...

  6. Boiling heat transfer modern developments and advances

    CERN Document Server

    Lahey, Jr, RT

    2013-01-01

    This volume covers the modern developments in boiling heat transfer and two-phase flow, and is intended to provide industrial, government and academic researchers with state-of-the-art research findings in the area of multiphase flow and heat transfer technology. Special attention is given to technology transfer, indicating how recent significant results may be used for practical applications. The chapters give detailed technical material that will be useful to engineers and scientists who work in the field of multiphase flow and heat transfer. The authors of all chapters are members of the

  7. Numerical and Experimental Investigation for Heat Transfer Enhancement by Dimpled Surface Heat Exchanger in Thermoelectric Generator

    Science.gov (United States)

    Wang, Yiping; Li, Shuai; Yang, Xue; Deng, Yadong; Su, Chuqi

    2016-03-01

    For vehicle thermoelectric exhaust energy recovery, the temperature difference between the heat exchanger and the coolant has a strong influence on the electric power generation, and ribs are often employed to enhance the heat transfer of the heat exchanger. However, the introduction of ribs will result in a large unwanted pressure drop in the exhaust system which is unfavorable for the engine's efficiency. Therefore, how to enhance the heat transfer and control the pressure drop in the exhaust system is quite important for thermoelectric generators (TEG). In the current study, a symmetrical arrangement of dimpled surfaces staggered in the upper and lower surfaces of the heat exchanger was proposed to augment heat transfer rates with minimal pressure drop penalties. The turbulent flow characteristics and heat transfer performance of turbulent flow over the dimpled surface in a flat heat exchanger was investigated by numerical simulation and temperature measurements. The heat transfer capacity in terms of Nusselt number and the pressure loss in terms of Fanning friction factors of the exchanger were compared with those of the flat plate. The pressure loss and heat transfer characteristics of dimples with a depth-to-diameter ratio ( h/D) at 0.2 were investigated. Finally, a quite good heat transfer performance with minimal pressure drop heat exchanger in a vehicle TEG was obtained. And based on the area-averaged surface temperature of the heat exchanger and the Seeback effect, the power generation can be improved by about 15% at Re = 25,000 compared to a heat exchanger with a flat surface.

  8. Area monitoring

    International Nuclear Information System (INIS)

    The exposure of individuals to ionizing radiation is normally subject to legal controls which specify limits, and restriction, of doses that both occupational workers and members of the public are exposed to. The dose limits recommended by the International Commission on Radiological Protection (ICRP), and adopted by many countries are specified in terms of body dose equivalents, sometimes referred to as limiting quantities. However these quantities are not measurable since they are defined as average doses in organs and tissues of the human body. Thus for the same physical radiation field the dose delivered to an individual will not have a fixed value but will depend upon each individual's sex, age and physical construction as well as upon their orientation in the field. Ionizing radiation, also, cannot be detected by a person's physical senses of sight, smell, hearing and touch. Thus to control the levels of radiation to which individuals are exposed, special operational quantities are used and quantitative measurements have to be made using personal dosemeters or area monitoring equipment. This report describes the operational quantities that are being increasingly used worldwide for area monitoring. It provides information on the international standards that are available on the performance requirements for monitoring equipment designed to measure these operational quantities. It also reviews the recent international standards that have been published on the calibration and type testing of area monitors and gives an example of legislative requirements on area monitoring equipment. (author)

  9. Effective Area

    Directory of Open Access Journals (Sweden)

    Ehud Keinan

    2015-07-01

    Full Text Available This article defines a new term, Effective Area, K, of a given territory as a function of four independent parameters: its nominal acreage, A, the intellectual competence of its inhabitants, B, their social competence, C, and their global influence, D, using a simple formalism: K = A x B x C x D. This analysis demonstrates that in our current world any consideration of the physical area of a given territory is meaningless if the quality of its population is ignored. K is a much more useful parameter than A, certainly for political and economical considerations, explaining why claims for territorial expansion are placed low on the national ladder of priorities in the developed countries. In many respects, large geographical areas may become a burden rather than an advantage. Thus, the importance of armed conflicts over geographical territories, which have taken a dominant part of the entire human history, is fading away. Furthermore, although the global acreage is constant, the total effective area of planet Earth keeps growing, providing sufficient room for the growing human population.

  10. Single Electrode Heat Effects

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Broers, G. H. J.

    1977-01-01

    The heat evolution at a single irreversibly working electrode is treated onthe basis of the Brønsted heat principle. The resulting equation is analogous to the expression for the total heat evolution in a galvanic cellwith the exception that –DeltaS is substituted by the Peltier entropy, Delta......SP, of theelectrode reaction. eta is the overvoltage at the electrode. This equation is appliedto a high temperature carbonate fuel cell. It is shown that the Peltier entropyterm by far exceeds the heat production due to the irreversible losses, and thatthe main part of heat evolved at the cathode is reabsorbed...

  11. Principle of uniformity of temperature difference field in heat exchanger

    Institute of Scientific and Technical Information of China (English)

    过增元; 李志信; 周森泉; 熊大曦

    1996-01-01

    A principle of uniformity of temperature difference field (TDF) in heat exchangers is advanced.It states that the more uniform the temperature difference field,the higher the effectiveness of heat exchanger for a given NTU and C,.Analytical and numerical results on the uniformity of TDF and effectiveness of thirteen types of heat exchangers show the validity of the uniformity principle.Its further verification is given by the asymptotical solution of TDF in terms of a recurrence formula of heat transfer area distribution.The analyses of entropy generation caused by heat transfer indicate that the uniformity principle is based on the second law of thermodynamics.Two ways,redistributing heat transfer areas and varying the connection between tubes,are presented for the improvement of the uniformity of TDF and the consequent increase of effectiveness for crossflow heat exchangers.

  12. 库尔勒垦区2000-2009年热量资源变化对棉花生产的影响%Influence of Heat Energy Resources Change on Cotton Production in Kolra Reclamation Area in 2000-2009

    Institute of Scientific and Technical Information of China (English)

    曹娟; 杜峰; 陈海莉

    2012-01-01

    利用库尔勒垦区29团气象站2000-2009年气象资料,分别对垦区近10a稳定通过10、15、20℃界限温度的初、终日期,持续日数,积温及无霜期变化进行了分析。结果表明:近10a库尔勒垦区各界限温度的初日偏早、终日偏晚;稳定通过各界限温度的持续日数均多于历年;各界限温度积温均呈上升趋势;无霜期日数呈略下降趋势且近10a平均初霜日偏早,终霜日明显推迟。棉花是喜温喜光作物,在棉花播种期、苗期、蕾期及花铃期对热量资源都有一定的需求,对热量资源与相应年份棉花单产的相关分析,得出热量资源丰富年份棉花单产较高等结论。%Based on the meteorological data from the observation at the 29th regiment in Korla reclamation area from :2000 to 2009, changes of heat indices including the beginning and ending dates, duration days, accumulative temperature, the frost-free period when the temperature steadily went higher than three critical temperatures (10℃, 15℃ ,20℃ ) were analyzed respectively. The results showed that the beginning dates of each critical temperature were earlier while the ending dates of that were later than normal. Duration days which went above three critical temperatures were all steadily more than the normal. The accumulative temperature of three boundaries presented the increasing trend. Duration days of frost-free period decreased slightly. The average first frost dates advanced, and the last frost dates postponed obviously. Now that cotton is a kind of thermophilic and light-preferring crop, and it has certain requirement of heat resources during its periods of sowing, seedling, budding and flowering. Correlation analysis between heat resources and per-square-meter yield of cotton in the corresponding year indicated that per-square-meter yield of cotton was higher in richer heat resource years.

  13. District Heating System Using Heat Pump Installations and CHP

    Directory of Open Access Journals (Sweden)

    Sit M.L.

    2015-12-01

    Full Text Available The article describes the district heating system, in which part of the heat of return water thermal power is used to supply heat to the district heating puThe article describes the district heating system, in which part of the heat of return water thermal power is used to supply heat to the district heating pumps, evaporators heating and hot water. Heat pumps use carbon dioxide as refrigerant. During the transitional period of the year, and the summer heat pump for preparing hot-water supply system uses the heat of the surrounding air. The heat of the ambient air is used in the intermediate heat exchanger between the first and second stages of the heat pump to cool the gas after the first stage of the compressor of the heat pump.

  14. Comparison of heat transfer efficiency between heat pipe and tube bundles heat exchanger

    OpenAIRE

    Wu Zhao-Chun; Zhu Xiang-Ping

    2015-01-01

    A comparison of heat transfer efficiency between the heat pipe and tube bundles heat exchanger is made based on heat transfer principle and the analysis of thermal characteristics. This paper argues that although heat pipe has the feature of high axial thermal conductivity, to those cases where this special function of heat transfer is unnecessary, heat pipe exchanger is not a high efficient heat exchanger when it is just used as a conventional heat exchang...

  15. Contrasting urban and rural heat stress responses to climate change

    Science.gov (United States)

    Fischer, E. M.; Oleson, K. W.; Lawrence, D. M.

    2012-02-01

    Hot temperatures in combination with high humidity cause human discomfort and may increase morbidity and mortality. A global climate model with an embedded urban model is used to explore the urban-rural contrast in the wet-bulb globe temperature, a heat stress index accounting for temperature and humidity. Wet-bulb globe temperatures are calculated at each model time step to resolve the heat stress diurnal cycle. The model simulates substantially higher heat stress in urban areas compared to neighbouring rural areas. Urban humidity deficit only weakly offsets the enhanced heat stress due to the large night-time urban heat island. The urban-rural contrast in heat stress is most pronounced at night and over mid-latitudes and subtropics. During heatwaves, the urban heat stress amplification is particularly pronounced. Heat stress strongly increases with doubled CO2 concentrations over both urban and rural surfaces. The tropics experience the greatest increase in number of high-heat-stress nights, despite a relatively weak ˜2°C warming. Given the lack of a distinct annual cycle and high relative humidity, the modest tropical warming leads to exceedance of the present-day record levels during more than half of the year in tropical regions, where adaptive capacity is often low. While the absolute urban and rural heat stress response to 2 × CO2 is similar, the occurrence of nights with extremely high heat stress increases more in cities than surrounding rural areas.

  16. Heat transfer performance of a novel double-layer mini-channel heat sink

    Science.gov (United States)

    Tang, Biao; Zhou, Rui; Bai, Pengfei; Fu, Ting; Lu, Longsheng; Zhou, Guofu

    2016-07-01

    High pressure drop and significant non-uniformity in temperature distribution along the streamwise direction are still challenges to the design of mini-channel heat sink. High density mini-channel arrays with high liquid-wall contact area are usually pursued in a conventional single-layer design of heat sink, which also inevitably brings high pressure drop. A novel double-layer structured heat sink is proposed in this paper. Four heat sinks with various designs in mini-channel density and flow direction were fabricated and studied experimentally on the heat transfer performance. The single factor of heat load does not show obvious effect on the overall thermal resistance of the heat sinks. On the other hand, slight decrease in thermal resistance was found with the increase in heat load at high flow rates. Moreover, a computational fluid dynamics modeling work was conducted. The results indicate that the parallel cross-flow field regulated by the double-layer structure enhances the heat exchange in both horizontal and vertical directions and consequently gives an uniform temperature distribution and high heat transfer efficiency.

  17. State Heating Oil & Propane Program. Final report 1997/98 heating season

    Energy Technology Data Exchange (ETDEWEB)

    Hunton, G.

    1998-06-01

    The following is a summary report of the New Hampshire Governor`s Office of Energy and Community Services (ECS) participation in the State Heating Oil and Propane Program (SHOPP) for the 1997/98 heating season. SHOPP is a cooperative effort, linking energy offices in East Coast and Midwest states, with the Department of Energy (DOE), Energy Information Administration (EIA) for the purpose of collecting retail price data for heating oil and propane. The program is funded by the participating state with a matching grant from DOE. SHOPP was initiated in response to congressional inquires into supply difficulties and price spikes of heating oil and propane associated with the winter of 1989/90. This is important to New Hampshire because heating oil controls over 55% of the residential heating market statewide. Propane controls 10% of the heating market statewide and is widely used for water heating and cooking in areas of the state where natural gas is not available. Lower installation cost, convenience, lower operating costs compared to electricity, and its perception as a clean heating fuel have all worked to increase the popularity of propane in New Hampshire and should continue to do so in the future. Any disruption in supply of these heating fuels to New Hampshire could cause prices to skyrocket and leave many residents in the cold.

  18. Experimental research on heat transfer in a coupled heat exchanger

    OpenAIRE

    Liu Yin; Ma Jing; Zhou Guang-Hui; Guan Ren-Bo

    2013-01-01

    The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more tha...

  19. District heating versus local heating - Social supportability

    International Nuclear Information System (INIS)

    District heating, DH, is an energy source which can provide a cost-effective, environmentally friendly source of heat and power for cities, but only in the case of well running systems, with reasonable technological losses. The benefits of DH system are well known: environmental friendly, energy security, economic and social advantages. DH already covers 60% of heating and hot water needs in transition economies. Today, 70 % of Russian, Latvian and Belarus homes use DH, and heating accounts for one-third of total Russian energy consumption. Yet a large number of DH systems in the region face serious financial, marketing or technical problems because of the policy framework. How can DH issues be best addressed in national and local policy? What can governments do to create the right conditions for the sustainable development of DH while improving service quality? What policies can help capture the economic, environmental and energy security benefits of co-generation and DH? To address these questions, the International Energy Agency (IEA) hosted in 2002 and 2004 conference focusing on the crucial importance of well-designed DH policies, for exchanging information on policy approaches. The conclusions of the conference have shown that 'DH systems can do much to save energy and boost energy security, but stronger policy measures are needed to encourage wise management and investment. With a stronger policy framework, DH systems in formerly socialist countries could save the equivalent of 80 billion cubic meters of natural gas a year through supply side efficiency improvements. This is greater than total annual natural gas consumption in Italy'. More efficient systems will also decrease costs, reducing household bills and making DH competitive on long-term. This paper presents the issues: -Theoretical benefits of the district heating and cooling systems; - Municipal heating in Romania; - Technical and economic problems of DH systems and social supportability; - How

  20. Absorption heat pumps

    Science.gov (United States)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  1. 24 CFR 3280.506 - Heat loss/heat gain.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Heat loss/heat gain. 3280.506... URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.506 Heat loss/heat gain. The manufactured home heat loss/heat gain shall be determined by methods outlined...

  2. Fragmentation of suddenly heated liquids

    International Nuclear Information System (INIS)

    Fragmentation of free liquids in Inertial Confinement Fusion reactors could determine the upper bound on reactor pulse rate. The x-ray ablated materials must cool and recondense to allow driver beam propagation. The increased surface area caused by fragmentation will enhance the cooling and condensation rates. Relaxation from the suddenly heated state will move a liquid into the negative pressure region under the liquid-vapor P-V dome. The lithium equation of state was used to demonstrate that neutron-induced vaporization uses only a minor fraction of the added heat, much less than would be required to drive the expansion. A 77% expansion of the lithium is required before the rapid vaporization process of spinodal decomposition could begin, and nucleation and growth are too slow to contribute to the expansion

  3. A thermosyphon heat pipe cooler for high power LEDs cooling

    Science.gov (United States)

    Li, Ji; Tian, Wenkai; Lv, Lucang

    2016-08-01

    Light emitting diode (LED) cooling is facing the challenge of high heat flux more seriously with the increase of input power and diode density. The proposed unique thermosyphon heat pipe heat sink is particularly suitable for cooling of high power density LED chips and other electronics, which has a heat dissipation potential of up to 280 W within an area of 20 mm × 22 mm (>60 W/cm2) under natural air convection. Meanwhile, a thorough visualization investigation was carried out to explore the two phase flow characteristics in the proposed thermosyphon heat pipe. Implementing this novel thermosyphon heat pipe heat sink in the cooling of a commercial 100 W LED integrated chip, a very low apparent thermal resistance of 0.34 K/W was obtained under natural air convection with the aid of the enhanced boiling heat transfer at the evaporation side and the enhanced natural air convection at the condensation side.

  4. Strong eddy compensation for the Gulf Stream heat transport

    Science.gov (United States)

    Saenko, Oleg A.

    2015-12-01

    Using a high-resolution ocean model forced with high-resolution atmospheric fields, a 5 year mean heat budget of the upper ocean in the Gulf Stream (GS) region is analyzed. The heat brought to the region with the mean flows along the GS path is 2-3 times larger than the heat loss to the atmosphere, with the difference being balanced by a strong cooling effect due to lateral eddy heat fluxes. However, over a broad area off the Grand Banks, the eddies warm the uppermost ocean layers, partly compensating for the loss of heat to the atmosphere. The upward eddy heat flux, which brings heat from the deeper ocean to the upper layers, is 30-80% of the surface heat loss.

  5. Mapping of low temperature heat sources in Denmark

    DEFF Research Database (Denmark)

    Bühler, Fabian; Holm, Fridolin Müller; Huang, Baijia;

    2015-01-01

    heat. The total accessible waste heat potential is found to be approximately 266 PJ per year with 58 % of it below 100 °C. In the natural heat category, temperatures below 20 °C originate from ambient air, sea water and shallow geothermal energy, and temperatures up to 100 °C are found for solar...... and deep geothermal energy. The theoretical solar thermal potential alone would be above 500 PJ per year. For the development of advanced thermodynamic cycles for the integration of heat sources in the Danish energy system, several areas of interest are determined. In the maritime transport sector a high......Low temperature heat sources are available in many applications, ranging from waste heat from industrial processes and buildings to geothermal and solar heat sources. Technical advancements, such as heat pumps with novel cycle design and multi-component working fluids, make the utilisation of many...

  6. An alternative method to characterize the surface urban heat island

    OpenAIRE

    Martin, Philippe; Baudouin, Yves; Gachon, Philippe

    2014-01-01

    An urban heat island (UHI) is a relative measure defined as a metropolitan area that is warmer than the surrounding suburban or rural areas. The UHI nomenclature includes a surface urban heat island (SUHI) definition that describes the land surface temperature (LST) differences between urban and suburban areas. The complexity involved in selecting an urban core and external thermal reference for estimating the magnitude of a UHI led us to develop a new definition of SUHIs that excludes any ru...

  7. Silicon Heat Pipe Array

    Science.gov (United States)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  8. Challenges in Smart Low-Temperature District Heating Development

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia

    2014-01-01

    Previous research and development shows that low temperature district heating (LTDH) system is economic feasible for low energy buildings and buildings at sparse areas. Coupling with reduced network temperature and well-designed district heating (DH) networks, LTDH can reduce network heat loss...... by up to 75% comparing with the current medium temperature district heating system. Further system efficiency improvement can be achieved through a holistic approach which includes measures such as reduced system design margin, enhanced demand side management and improved operation of decentralized heat...

  9. Floor heating maximizes residents` comfort

    Energy Technology Data Exchange (ETDEWEB)

    Tirkkanen, P.; Wikstroem, T.

    1996-11-01

    Storing heat in floors by using economical night-time electricity does not increase the specific consumption of heating. According to studies done by IVO, the optimum housing comfort is achieved if the room is heated mainly by means of floor heating that is evened out by window or ceiling heating, or by a combination of all three forms of heating. (orig.)

  10. The effect of heat generation in inclined slats on the natural convective heat transfer from an isothermal heated vertical plate

    International Nuclear Information System (INIS)

    Natural convective heat transfer from a wide heated vertical isothermal plate with adiabatic surfaces above and below the heated surface has been considered. There are a series of equally spaced vertical thin, flat surfaces (termed 'slats') near the heated surface, these surfaces being, in general, inclined to the heated surface. There is, in general, a uniform heat generation in the slats. The slats are pivoted about their centre-point and thus as their angle is changed, the distance of the tip of the slat from the plate changes. The situation considered is an approximate model of a window with a vertical blind, the particular case where the window is hotter than the room air being considered. The heat generation in the slats in this situation is the result of solar radiation passing through the window and falling on and being absorbed by the slats of the blind. The flow has been assumed to be laminar and steady. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces. The governing equations have been written in dimensionless form and the resulting dimensionless equations have been solved using a commercial finite-element package. The solution has the following parameters: (1) the Rayleigh number (2) the Prandtl number (3) the dimensionless heat generation rate in the slats per unit frontal area (4) the dimensionless distance of the slat center point (the pivot point) from the surface (5) the dimensionless slat size (6) the dimensionless slat spacing (7) the angle of inclination of the slats. Because of the application that motivated the study, results have only been obtained for a Prandtl number of 0.7. The effect of the other dimensionless variables on the mean dimensionless heat transfer rate from the heated vertical surface has been examined. (author)

  11. Localized rapid heating process for precision chalcogenide glass molding

    Science.gov (United States)

    Li, Hui; He, Peng; Yu, Jianfeng; Lee, L. James; Yi, Allen Y.

    2015-10-01

    Precision glass molding is an important process for high volume optical fabrication. However, conventional glass molding is a bulk heating process that usually requires a long thermal cycle, where molding assembly and other mechanical parts are heated and cooled together. This often causes low efficiency and other heating and cooling related problems, such as large thermal expansion in both the molds and molded optics. To cope with this issue, we developed a localized rapid heating process to effectively heat only very small part of the glass. This localized rapid heating study utilized a fused silica wafer coated with a thin graphene layer to heat only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating heat on and near the coating. The feasibility of this process was validated by both experiments and numerical simulation. To demonstrate the advantages of the localized rapid heating, both localized rapid heating process and bulk heating process were performed and carefully compared. The uniformity and quality of the molded sample by localized rapid heating process was also demonstrated. In summary, localized rapid heating process by using graphene coated fused silica wafer was characterized and can be readily implemented in replication of micro scale chalcogenide glasses. A fused silica wafer coated with a thin graphene layer was utilized for localized rapid heating only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating high temperature on and near the coating. This process is fast and efficient since only interested areas are heated without affecting the entire glass substrate or the mold assembly. The uniformity and quality of the molded sample by localized rapid heating process was demonstrated by comparing both localized rapid heating

  12. Sleeving repair of heat exchanger tubes

    International Nuclear Information System (INIS)

    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

  13. Performance characteristic of thermosyphon heat pipe at radiant heat source

    Science.gov (United States)

    Hrabovský, Peter; Papučík, Štefan; Kaduchová, Katarína

    2016-06-01

    This article discusses about device, which is called heat pipe. This device is with heat source with radiant heat source. Heat pipe is device with high efficiency of heat transfer. The heat pipe, which is describe in this article is termosyphon heat pipe. The experiment with termosyphon heat pipe get a result. On the base of result, it will be in future to create mathematical model in Ansys. Thermosyphon heat pipe is made of copper and distilled water is working fluid. The significance of this experiment consists in getting of the heat transfer and performance characteristic. On the basis of measured and calculated data can be constructed the plots.

  14. Experimental research on heat transfer in a coupled heat exchanger

    Directory of Open Access Journals (Sweden)

    Liu Yin

    2013-01-01

    Full Text Available The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more than 35%, and the average heating efficiency increases more than 55%, compared with the ordinary air-source heat pump.

  15. Heat-pipe Earth.

    Science.gov (United States)

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

  16. Fluidized bed heat treating system

    Energy Technology Data Exchange (ETDEWEB)

    Ripley, Edward B; Pfennigwerth, Glenn L

    2014-05-06

    Systems for heat treating materials are presented. The systems typically involve a fluidized bed that contains granulated heat treating material. In some embodiments a fluid, such as an inert gas, is flowed through the granulated heat treating medium, which homogenizes the temperature of the heat treating medium. In some embodiments the fluid may be heated in a heating vessel and flowed into the process chamber where the fluid is then flowed through the granulated heat treating medium. In some embodiments the heat treating material may be liquid or granulated heat treating material and the heat treating material may be circulated through a heating vessel into a process chamber where the heat treating material contacts the material to be heat treated. Microwave energy may be used to provide the source of heat for heat treating systems.

  17. Does light attract piglets to the creep area?

    DEFF Research Database (Denmark)

    Larsen, Mona Lilian Vestbjerg; Pedersen, Lene Juul

    2015-01-01

    of the creep area and whether light in the creep area works as an attractant on piglets. A total of 39 sows, divided between two batches, were randomly distributed to three heat source treatments: (1) standard infrared heat lamp (CONT, n=19), (2) eHeat with light (EL, n=10) and (3) eHeat without light (ENL, n...... and was lower in batch 1 compared with batch 2. Seen from the present results, neither eHeat nor light worked as an attractant on piglets; in contrast, piglets preferred to sleep in the dark and it would therefore be recommended to turn off the light in the creep area during darkness. Heating up the creep area...

  18. About the possible options for models of convective heat transfer in closed volumes with local heating source

    Directory of Open Access Journals (Sweden)

    Maksimov Vyacheslav I.

    2015-01-01

    Full Text Available Results of mathematical modeling of convective heat transfer in air area surrounded on all sides enclosing structures, in the presence of heat source at the lower boundary of the media are presented. Solved the system of differential equations of unsteady Navier-Stokes equations with the appropriate initial and boundary conditions. The process of convective heat transfer is calculated using the models of turbulence Prandtl and Prandtl-Reichard. Takes into account the processes of heat exchange region considered with the environment. Is carried out the analysis of the dimensionless heat transfer coefficient at interfaces “air – enclosures”. The distributions average along the gas temperature range are obtained.

  19. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  20. HEAT TRANSFER FLUIDS

    OpenAIRE

    Lenert, Andrej; Nam, Youngsuk; Wang, Evelyn N.

    2012-01-01

    The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based on a new figure of merit capturing the combined effects of thermal storage capacity, convective heat transfer characteristics, and hydraulic performance of the fluids. Thermal stability, freezing point, and safety issues are also discussed. Through a comparative analysis, we...

  1. Convection heat transfer

    CERN Document Server

    Bejan, Adrian

    2013-01-01

    Written by an internationally recognized authority on heat transfer and thermodynamics, this second edition of Convection Heat Transfer contains new and updated problems and examples reflecting real-world research and applications, including heat exchanger design. Teaching not only structure but also technique, the book begins with the simplest problem solving method (scale analysis), and moves on to progressively more advanced and exact methods (integral method, self similarity, asymptotic behavior). A solutions manual is available for all problems and exercises.

  2. Mechanisms of Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma

    2006-06-01

    The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar corona. Recent observations show that Magnetic Carpet is a potential candidate for solar coronal heating.

  3. Heat and thermodynamics

    CERN Document Server

    Saxena, A K

    2014-01-01

    Heat and thermodynamics aims to serve as a textbook for Physics, Chemistry and Engineering students. The book covers basic ideas of Heat and Thermodynamics, Kinetic Theory and Transport Phenomena, Real Gases, Liquafaction and Production and Measurement of very Low Temperatures, The First Law of Thermodynamics, The Second and Third Laws of Thermodynamics and Heat Engines and Black Body Radiation. KEY FEATURES Emphasis on concepts Contains 145 illustrations (drawings), 9 Tables and 48 solved examples At the end of chapter exercises and objective questions

  4. Counterflow Regolith Heat Exchanger

    Science.gov (United States)

    Zubrin, Robert; Jonscher, Peter

    2013-01-01

    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  5. NCSX Plasma Heating Methods

    Energy Technology Data Exchange (ETDEWEB)

    H.W. Kugel; D. Spong; R. Majeski; M. Zarnstorff

    2003-02-28

    The NCSX (National Compact Stellarator Experiment) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral-beam injection, and radio-frequency. Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The plan is to provide 3 MW of 50 keV balanced neutral-beam tangential injection with pulse lengths of 500 msec for initial experiments, and to be upgradeable to pulse lengths of 1.5 sec. Subsequent upgrades will add 3 MW of neutral-beam injection. This Chapter discusses the NCSX neutral-beam injection requirements and design issues, and shows how these are provided by the candidate PBX-M (Princeton Beta Experiment-Modification) neutral-beam injection system. In addition, estimations are given for beam-heating efficiencies, scaling of heating efficiency with machine size an d magnetic field level, parameter studies of the optimum beam-injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of radio-frequency heating by mode-conversion ion-Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron-cyclotron heating. The initial MCIBW heating technique and the design of the radio-frequency system lend themselves to current drive, so that if current drive became desirable for any reason only minor modifications to the heating system described here would be needed. The radio-frequency system will also be capable of localized ion heating (bulk or tail), and possibly ion-Bernstein-wave-generated sheared flows.

  6. NCSX Plasma Heating Methods

    Energy Technology Data Exchange (ETDEWEB)

    Kugel, H. W.; Spong, D.; Majeski, R.; Zarnstorff, M.

    2008-01-18

    The National Compact Stellarator Experiment (NCSX) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral beam injection, and radio-frequency (rf). Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, neutral beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The experimental plan requires 3 MW of 50-keV balanced neutral beam tangential injection with pulse lengths of 500 ms for initial experiments, to be upgradeable to pulse lengths of 1.5 s. Subsequent upgrades will add 3MW of neutral beam injection (NBI). This paper discusses the NCSX NBI requirements and design issues and shows how these are provided by the candidate PBX-M NBI system. In addition, estimations are given for beam heating efficiencies, scaling of heating efficiency with machine size and magnetic field level, parameter studies of the optimum beam injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of rf heating by mode conversion ion Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron cyclotron heating. The initial MCIBW heating technique and the design of the rf system lend themselves to current drive, so if current drive became desirable for any reason, only minor modifications to the heating system described here would be needed. The rf system will also be capable of localized ion heating (bulk or tail), and possiblyIBW-generated sheared flows.

  7. Magnetic Flux Controllers for Induction Heating Applications

    Institute of Scientific and Technical Information of China (English)

    Valentin Nemkov; Robert Goldstein; Robert Ruffini

    2004-01-01

    Application of magnetic flux controllers/concentrators to induction heating coils can drastically improve the process efficiency and heat pattern control. Presentation includes: benefits provided by flux controllers, materials available for controllers, application techniques, computer assisted design of induction coils with concentrators, examples of applications. Depending on induction system design, magnetic flux controllers can concentrate heating in a specified area,change heat source distribution and shield a particular part zone or external area preventing unintended eddy current heating.Besides of the coil efficiency improvement and optimal power distribution, magnetic flux controllers reduce the coil current demand from a supplying circuitry thus strongly reducing losses in busswork, cables, transformers and inverter components.Improvement that can be achieved due to magnetic flux controllers is case dependable. 2D and 3D computer simulation allows the designer to predict accurately effect of controllers on the coil parameters and temperature distribution and optimize the whole electromagnetic system. Special attention in presentation is paid to new magnetodielectric materials optimized for induction heating conditions. These materials have high magnetic permeability and saturation flux density,excellent machinability, good chemical and temperature resistance. Concentrators from these materials can work in a wide range of frequencies and specific powers. Examples of magnetic flux controller application include surface hardening of shafts and gears, induction surface hardfacing and brazing.

  8. An electrohydrodynamic heat pipe.

    Science.gov (United States)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  9. Heat Pipe Materials Compatibility

    Science.gov (United States)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  10. Heat Capacity Analysis Report

    International Nuclear Information System (INIS)

    The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore

  11. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir...

  12. Heat and mass exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2007-09-18

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  13. Heating uranium alloy billets

    International Nuclear Information System (INIS)

    Data were obtained for the surface heat transfer coefficient of uranium and the alloys of uranium-0.75 wt percent titanium, uranium-6 wt percent niobium, and uranium-7.5 wt percent niobium-2.5 wt percent zirconium. Samples were heated to 8500C in both a molten salt bath and an argon-purged air furnace, then the samples were cooled in air. Surface heat transfer coefficients were calculated from the experimental data for both heating and cooling of the metals. 4 fig, 4 tables

  14. Microplate Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple...

  15. Heat rejection system

    Science.gov (United States)

    Smith, Gregory C.; Tokarz, Richard D.; Parry, Jr., Harvey L.; Braun, Daniel J.

    1980-01-01

    A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

  16. Introduction to Heat Pipes

    Science.gov (United States)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  17. Comparative analysis of compact heat exchangers for application as the intermediate heat exchanger for advanced nuclear reactors

    International Nuclear Information System (INIS)

    Highlights: • Compact heat exchanger designs evaluated for advanced nuclear reactor applications. • Wavy channel PCHE compared with offset strip-fin heat exchanger (OSFHE). • 15° pitch angle wavy channel PCHE offers optimum performance characteristics. • OSFHE exhibits higher pressure drop and lower compactness than other options. • Comparison technique applicable for evaluating candidate heat exchangers designs. - Abstract: A comparative evaluation of alternative compact heat exchanger designs for use as the intermediate heat exchanger in advanced nuclear reactor systems is presented in this article. Candidate heat exchangers investigated included the Printed circuit heat exchanger (PCHE) and offset strip-fin heat exchanger (OSFHE). Both these heat exchangers offer high surface area to volume ratio (a measure of compactness [m2/m3]), high thermal effectiveness, and overall low pressure drop. Helium–helium heat exchanger designs for different heat exchanger types were developed for a 600 MW thermal advanced nuclear reactor. The wavy channel PCHE with a 15° pitch angle was found to offer optimum combination of heat transfer coefficient, compactness and pressure drop as compared to other alternatives. The principles of the comparative analysis presented here will be useful for heat exchanger evaluations in other applications as well

  18. Constraints and opportunities of geothermal district heating in northern Italy

    Energy Technology Data Exchange (ETDEWEB)

    Chierici, R. [CESEN S.P.A., Genova (Italy). Geothermal Sector; Carella, R. [Unione Geotermica Italiana, Milano (Italy)

    2000-09-01

    Northern Italy is the Italian area with higher potential for the development of DH Systems supplied by geothermal fluids due to the large availability of low-medium enthalpy geothermal resources, heat demand and climatic conditions. This area is identified mainly in the Po Valley bordered by the Alpine and Apennines foothills and includes five main geothermal sectors: Po basin, Ferrara uplift, Berici-Euganei hills Veneto plain, and South Piedmont trough. The geothermal applications so far developed in the area include DH systems or space heating and agricultural uses. In table 1 the main data for the main civil heating operations are summarized. (orig.)

  19. Heat-stimulus correction for pulsed-infrared thermography

    Science.gov (United States)

    Benítez, Hernán D.; Ibarra-Castanedo, Clemente; Bendada, AbdelHakim; Maldague, Xavier

    2009-05-01

    The modified DAC version with thermal quadrupoles can be considered an interesting alternative to thermal contrast computations since it provides an automated tool for depth retrieval and eliminates the need of selecting a non-defective area. In practice it is important to have heat stimulus with complex shapes and long durations (several seconds) in order to cover larger inspection areas, enhance thermal contrast between defective and sound areas and increase the depth of inspection inside the material. In this work we present a heat stimulus correction by using the thermal quadrupoles theory and its validation with several heat stimulus shapes and durations.

  20. Compact ground heat exchangers in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Hellstroem, G. [Dept. of Mathematical Physics, Lund Univ. (Sweden); Rosen, B. [Swedish Geotechnical Inst., Linkoeping (Sweden)

    2004-12-01

    About 30,000 ground-coupled heat pumps are currently installed each year in Sweden. Of these, 70-80% use vertical boreholes rock, whereas the remaining part uses horizontal loops. Vertical boreholes are considered to be a technically safer installation, since there is little risk of accidental damage to the pipes. The house owners also appreciate that there is less impact of excavation and possible frost heave in their garden. A research project aimed at developing compact shallow ground heat exchangers was started in 2001 as a cooperation between Lund University and the Swedish Geotechnical Institute funded by the Swedish Research Council FORMAS and the Swedish Energy Agency. The purpose is to reduce the ground area and the trench length required for installation of cost-effective ground heat exchangers in soil to be used in Swedish climatic and geological conditions. The project is carried out in cooperation with installers and heat pump manufacturers. (orig.)

  1. Micro-Scale Regenerative Heat Exchanger

    Science.gov (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2004-01-01

    A micro-scale regenerative heat exchanger has been designed, optimized and fabricated for use in a micro-Stirling device. Novel design and fabrication techniques enabled the minimization of axial heat conduction losses and pressure drop, while maximizing thermal regenerative performance. The fabricated prototype is comprised of ten separate assembled layers of alternating metal-dielectric composite. Each layer is offset to minimize conduction losses and maximize heat transfer by boundary layer disruption. A grating pattern of 100 micron square non-contiguous flow passages were formed with a nominal 20 micron wall thickness, and an overall assembled ten-layer thickness of 900 microns. Application of the micro heat exchanger is envisioned in the areas of micro-refrigerators/coolers, micropower devices, and micro-fluidic devices.

  2. Lunar Base Heat Pump

    Science.gov (United States)

    Walker, D.; Fischbach, D.; Tetreault, R.

    1996-01-01

    The objective of this project was to investigate the feasibility of constructing a heat pump suitable for use as a heat rejection device in applications such as a lunar base. In this situation, direct heat rejection through the use of radiators is not possible at a temperature suitable for lde support systems. Initial analysis of a heat pump of this type called for a temperature lift of approximately 378 deg. K, which is considerably higher than is commonly called for in HVAC and refrigeration applications where heat pumps are most often employed. Also because of the variation of the rejection temperature (from 100 to 381 deg. K), extreme flexibility in the configuration and operation of the heat pump is required. A three-stage compression cycle using a refrigerant such as CFC-11 or HCFC-123 was formulated with operation possible with one, two or three stages of compression. Also, to meet the redundancy requirements, compression was divided up over multiple compressors in each stage. A control scheme was devised that allowed these multiple compressors to be operated as required so that the heat pump could perform with variable heat loads and rejection conditions. A prototype heat pump was designed and constructed to investigate the key elements of the high-lift heat pump concept. Control software was written and implemented in the prototype to allow fully automatic operation. The heat pump was capable of operation over a wide range of rejection temperatures and cooling loads, while maintaining cooling water temperature well within the required specification of 40 deg. C +/- 1.7 deg. C. This performance was verified through testing.

  3. Experimental Study on Resistance to Bacterial Toxin Role for Ten Kinds Chinese Herb Medicines with Clearing away Heat and Toxic Material in Guangdong Area%10种广东本地清热解毒中草药抗细菌内毒素作用实验研究

    Institute of Scientific and Technical Information of China (English)

    张健民; 蒋三元; 李雁玲; 郑国燊; 唐荣德

    2011-01-01

    Objective: Explore the role of resistance to bacterial endotoxin for ten kinds Chinese herb medicines with the clearing away heat and toxic material in Guangdong area. Methods: The limulus reagent tests were used in vitro anti -endotoxin agglutinate reaction experiment. Results; Ten kinds Chinese herb medicines with the clearing away heat and toxic material in Guangdong area all have tuba] agglutinate reactions of resistance to limulus reagent ( namely, all have anti - bacterial endotoxin actions) when the concentration is in 1.0g/mL. Other Chinese herb medicines have anti - bacterial endotoxin actions besides Jin niu kou and Xi huang cao when the concentration is in 0.5g/mL and besides Jin niu kou.Xi huang cao and Gang mei gen when the concentration is in 0. 3g/mL. Tian ji huang,Hu lu cha and Jiu bi ying have anti - bacterial endotoxin actions when the concentration is in 0. Lg/mL. These results point out that the various medicinal materials have different anti - bacterial endotoxin actions. Conclusions: Ten kinds Chinese herb medicines with the clearing away heat and toxic material in Guangdong area all have the roles of resistance to bacterial endotoxin. Tian ji huang、Hu lu cha and Jiu bi ying have strongest actions. Jin niu kou, Xi huang cao have relatively weak actions.%目的:探讨10种广东本地清热解毒中草药的抗细菌内毒素作用.方法:采用鲎试剂试管凝集反应进行体外抗内毒素实验.结果:所研究的10种广东本地清热解毒中草药,药液浓度为1.0g/mL时,10种中草药均有抗鲎试剂试管凝集反应,均具有抗细菌内毒素的作用;调整浓度为0.5g/mL时,除金扭扣、溪黄草外,其余中草药具有抗细菌内毒素作用;浓度为0.3g/mL时,除金扭扣、溪黄草、岗梅根外,其余中草药具有抗细菌内毒素作用;浓度为0.1g/mL时,田基黄、葫芦茶、救必应具有抗细菌内毒素作用,提示不同的药材存在抗细菌内毒素作用的差异.结论:广东10种本地清

  4. Solar heating cooling. Preparation of possible participation in IEA, Solar Heating Cooling Task 25

    International Nuclear Information System (INIS)

    For the Danish solar heating industries it is interesting to discuss the domestic market possibilities and the export possibilities for solar heating cooling systems. The Danish solar heating sector also wants to participate in the international collaboration within IEA Solar Heating and Cooling Task 25 'Solar Assisted Air Conditioning of Buildings'. The Danish Energy Agency therefore has granted means for this project to discuss: The price of cooling for 3 different solar cooling methods (absorption cooling, desiccant cooling and ejector cooling); Market possibilities in Denmark and abroad; The advantages by Danish participation in IEA Task 25. The task has been solved through literature studies to establish status for the 3 technologies. It turned out that ejector cooling by low temperatures (85 deg. C from the solar collector) exists as pilot plants in relation to district heating, but is still not commercial accessible. Desiccant cooling, where the supplied heat has temperatures down to 55 deg. C is a well-developed technology. However only a handful of pilot plants with solar heating exists, and thus optimization relating to operation strategy and economy is on the experimental stage. Absorption cooling plants driven by solar heating are found in a large number in Japan and are also demonstrated in several other countries. The combination of absorption heating pump and solar heating is considered to be commercial accessible. Solar heating is interesting as heat source of to the extent that it can replace other sources of heat without the economy being depreciated. This can be the case in South Europe if: 1) oil or natural gas is used for heating; 2) a solar heating system already exists, e.g. for domestic water supply, and is installed so that the marginal costs by solar heating supply of the ventilation plant is reduced. All in all the above conditions mean that the market for solar heating for cooling is very limited in Europe, where almost everybody are

  5. Analysis of thermosyphon heat exchangers for use in solar domestic hot water heating systems

    Science.gov (United States)

    Dahl, Scott David

    1998-11-01

    A recent innovation in the solar industry is the use of thermosyphon heat exchangers. Determining the performance of these systems requires knowledge of how thermosyphon flow rate and heat exchanger performance vary with operating conditions. This study demonstrates that several thermosyphon heat exchanger designs operate in the laminar mixed convection regime. Empirical heat transfer and pressure drop correlations are obtained for three tube-in-shell heat exchangers (four, seven, and nine tube). Thermosyphon flow is on the shell side. Correlations are obtained with uniform heat flux on the tube walls and with a mixture of glycol and water circulating inside the tubes. Ranges of Reynolds, Prandtl, and Grashof numbers are 50 to 1800, 2.5 and 6.0, and 4×105 to 1×108, respectively. Nusselt number correlations are presented in a form that combines the contributions of forced and natural convection, Nu4Mixed=Nu4Forced+Nu4Natural. The Nusselt number is influenced by natural convection when the term Raq0.25/(Re0.5Pr0.33) is greater than unity. Pressure drop through these three designs is not significantly affected by mixed convection because most pressure drop losses are at the heat exchanger inlet and outlet. A comparison and discussion of the performance of several other heat exchanger designs (tube-in-shell and coil-in- shell designs) are presented. Generally, the coil-in- shell heat exchangers perform better than the tube-in- shell heat exchangers. Data from all heat exchanger designs is used to develop a new one-dimensional model for thermosyphon heat exchangers in solar water heating systems. The model requires two empirically determined relationships, pressure drop as a function of water mass flow rate and the overall heat transfer coefficient-area product (UA) as a function of Reynolds, Prandtl, and Grashof number. A testing protocol is presented that describes the procedure to obtain the data for the correlations. Two new TRNSYS component models are presented

  6. Solar/electric heating systems for the future energy system

    Energy Technology Data Exchange (ETDEWEB)

    Furbo, S.; Dannemand, M.; Perers, B. [and others

    2013-05-15

    The aim of the project is to elucidate how individual heating units for single family houses are best designed in order to fit into the future energy system. The units are based on solar energy, electrical heating elements/heat pump, advanced heat storage tanks and advanced control systems. Heat is produced by solar collectors in sunny periods and by electrical heating elements/heat pump. The electrical heating elements/heat pump will be in operation in periods where the heat demand cannot be covered by solar energy. The aim is to use the auxiliary heating units when the electricity price is low, e.g. due to large electricity production by wind turbines. The unit is equipped with an advanced control system where the control of the auxiliary heating is based on forecasts of the electricity price, the heat demand and the solar energy production. Consequently, the control is based on weather forecasts. Three differently designed heating units are tested in a laboratory test facility. The systems are compared on the basis of: 1) energy consumption for the auxiliary heating; 2) energy cost for the auxiliary heating; 3) net utilized solar energy. Starting from a normal house a solar combi system (for hot water and house heating) can save 20-30% energy cost, alone, depending on sizing of collector area and storage volume. By replacing the heat storage with a smart tank based on electric heating elements and a smart control based on weather/load forecast and electricity price information 24 hours ahead, another 30-40% can be saved. That is: A solar heating system with a solar collector area of about 10 m{sup 2}, a smart tank based on electric heating element and a smart control system, can reduce the energy costs of the house by at least 50%. No increase of heat storage volume is needed to utilize the smart control. The savings in % are similar for different levels of building insulation. As expected a heat pump in the system can further reduce the auxiliary electricity

  7. Space Heating in Sweden 2009; Uppvaermning i Sverige 2009

    Energy Technology Data Exchange (ETDEWEB)

    2009-06-15

    therefore important that a heat pump has a high coefficient of performance, that a wood burning boiler is efficient and that the district heat is produced and distributed effectively. It not possible to say which type of heating system is best environmentally. An effective heat pump with environmentally friendly electricity might be at least as good as district heating. Solar is by far the cleanest heating option but fails to warm the house throughout the year. Oil has a high environmental impact in all areas. Natural gas boilers have good environmental values in all areas except the greenhouse effect. Biofuel pellet boilers and wood burning boilers has a medium impact on the environment in relation to the other heating systems in terms of acidification, eutrophication and particulate matter but a major environmental advantage in terms of greenhouse effect. Financial support is given for conversion from direct-acting electricity to district heating, lake or ground source heat pumps. Furthermore, support is provided for conversion to heating with biofuel where the direct-acting electricity is replaced wholly or partly with a water-based heating systems. Most conversions from direct-acting electricity is made to district heating

  8. Heat capacity and thermodynamic functions of dimethyltellurium

    International Nuclear Information System (INIS)

    Temperature dependence of dimethyl-tellurium heat capacity (DMT) in the area of 6-308 K is studied in a vacuum adiabatic calorimeter. Temperature, enthalpy and melting entropy of the DMT high-temperature crystal modification are determined. The S Deg(T), H Deg(T)-H Deg(0) and G Deg(T)-H Deg(0) thermodynamic functions in the studied temperature areas function of the DMT formation in liquid and gaseous state at 298.15 K are calculated

  9. Experimental evaluation of the heat transfer performance of sodium heated once through steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Vinod, V., E-mail: vvinod@igcar.gov.in; Sivakumar, L.S.; Kumar, V.A. Suresh; Noushad, I.B.; Padmakumar, G.; Rajan, K.K.

    2014-07-01

    Highlights: • PFBR has eight units of steam generators to transfer 1250 MWt power. • A model steam generator was tested for its heat transfer performance. • The model steam generator transferred 6.05 MWt power at nominal conditions. • To produce steam at nominal conditions 91.7% of area is sufficient. • The steam generator design for PFBR is validated by experiments. - Abstract: Steam generator is a crucial component in a nuclear power plant because its availability is directly linked to the availability of heat transport system and thus the plant availability. In Prototype Fast Breeder Reactor (PFBR) which is in advanced stage of construction in India, eight number of steam generators each with a heat transfer capacity of 156 MWt transfers 1250 MW of heat from secondary sodium to the conventional steam/water system. The sodium heated once through steam generator with 23 m long seamless straight tubes produces super heated steam at 17.2 MPa pressure and 493 °C temperature. A model steam generator of 5.5 MWt power was tested in steam generator test facility of Indira Gandhi Center for Atomic research for validating the thermal hydraulic and mechanical design of the steam generator. The testing revealed the adequacy of heat transfer capability of the steam generator to transfer the intended power. From the experimental data it is estimated that the steam generator has 8.3% more tube surface area than the required to produce steam at nominal conditions. This paper gives the details of the model steam generator, heat transfer experiments conducted to validate the thermal design and the method for estimating the additional heat transfer area in once through type steam generator.

  10. Gel fire suppressants for controlling underground heating

    Institute of Scientific and Technical Information of China (English)

    HU Sheng-gen; XUE Sheng

    2011-01-01

    One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines.CSIRO researchers have developed a number of polymer gels suitable for controlling heatings in coal mines.These gels were developed to meet strict selection criteria including easy preparation,no or low toxicity,controllable gelation time,adaptable to mine water chemistry,adjustable viscosity,relatively long gel life,thermally and chemically stable and low cost.The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in underground coal mines.These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.

  11. Geothermal resource area 3: Elko County. Area development plan

    Energy Technology Data Exchange (ETDEWEB)

    Pugsley, M.

    1981-01-01

    Geothermal Resource Area 3 includes all of the land in Elko County, Nevada. There are in excess of 50 known thermal anomalies in this area. Several of the more major resources have been selected for detailed description and evaluation in this Area Development Plan. The other resources are considered too small, too low in temperature, or too remote to be considered for development in the near future. Various potential uses of the energy found at each of the studied resource sites in Elko County were determined after evaluating the area's physical characteristics; the land ownership and land use patterns; existing population and projected growth rates; transportation facilities and energy requirements. These factors were then compared with resource site specific data to determine the most likely uses of the resource. The uses considered in this evaluation were divided into five main categories: electrical generation, space heating, recreation, industrial process heat, and agriculture. Within two of these categories several subdivisions were considered separately. It was determined that several of the geothermal resources evaluated in the Area Development Plan could be commercially developed. The potential for development for the seven sites considered in this study is summarized.

  12. 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...

  13. Limitations of floor heating - optimum heating surface design. Grenzen der Deckenheizung - optimale Heizflaechengestaltung

    Energy Technology Data Exchange (ETDEWEB)

    Glueck, B.

    1994-06-01

    The publication on the use of cooling floors for heating purposes has resulted in the following questions amongst the professionals: Can rooms with relatively poor thermal insulation and customary outside air filtration, also be thermophysiologically heated in a permissible manner with radiant floor surfaces How do corner areas behave Can the radiator design be optimized where radiated temperature distribution is concerned The effects and the present limitations are indicated by means of practical examples. (orig.)

  14. Passive Vaporizing Heat Sink

    Science.gov (United States)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

    2011-01-01

    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  15. Heat supply project Sent

    Energy Technology Data Exchange (ETDEWEB)

    Studach, J.

    1981-05-01

    The aim to get back to energy autarky with heat generation plants from 1 to 5 MW capacity and a distribution network is becoming more and more attractive for small communities like the village Sent in Switzerland, especially since energy sources have become more and more scarce. The operation of a communal heating station and the maintenance of a heat distribution network is a task which the community will be able to cope with like water supply and waste disposal. The pilot project was handed in June 1980, all efforts are at the moment directed at realising it at the quickest possible pace. Long-term experience is needed urgently even though there are reality oriented accompanying test projects like wood-gas-dual-purpose power plants and the new collector-air-to-water heat exchanger element and distant heat pipes. A booklet supplies information on the domestic heat demand, heat generation with wood gas, wood supply, ambient air and sun, heat distribution and delivery, building installations, costs of construction and operation.

  16. Introductory heat-transfer

    Science.gov (United States)

    Widener, Edward L.

    1992-01-01

    The objective is to introduce some concepts of thermodynamics in existing heat-treating experiments using available items. The specific objectives are to define the thermal properties of materials and to visualize expansivity, conductivity, heat capacity, and the melting point of common metals. The experimental procedures are described.

  17. Radioisotopic heat source

    International Nuclear Information System (INIS)

    Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 15700F to about 17200F for about one h

  18. Heat pump for heat recovery with superheated vapor

    Directory of Open Access Journals (Sweden)

    Liu Yin

    2015-01-01

    Full Text Available A heat pump for heat recovery is designed to produce hot water through recovering the heat from the superheated vapor and hot refrigerant in the condenser. The experimental results show that performance of the heat pump system with superheated vapor heat exchanger has obvious superiority over the regular condenser for hot water production.

  19. Heat pump for heat recovery with superheated vapor

    OpenAIRE

    Liu Yin; Ma Jing; Zhou Guang-Hui; Wan Wen-Lei

    2015-01-01

    A heat pump for heat recovery is designed to produce hot water through recovering the heat from the superheated vapor and hot refrigerant in the condenser. The experimental results show that performance of the heat pump system with superheated vapor heat exchanger has obvious superiority over the regular condenser for hot water production.

  20. Heat pipes and use of heat pipes in furnace exhaust

    Science.gov (United States)

    Polcyn, Adam D.

    2010-12-28

    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  1. Solar-heating system design data brochure

    Science.gov (United States)

    1979-01-01

    Report details design and performance specifications of complete system for space and hot-water heating that is assembled from commercially available components. System can meet need of single family dwelling having approximately 1,200 sq ft of floor area and can be scaled to requirements of larger or smaller installations.

  2. Solar-heating and cooling demonstration project

    Science.gov (United States)

    1980-01-01

    Florida Solar Energy Center has retrofitted office building, approximately 5,000 square feet of area, with solar heating and air-conditioning. Information on operation, installation, controls, and hardware for system is contained in 164 page report. Document includes manufacturer's product literature and detailed drawings.

  3. Heat tolerance in wheat

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari

    and quantitative genetics in particular, plant phenotyping based quantitative trait loci (QTL) discovery for a physiological trait under heat stress. Chlorophyll a fluorescence trait, Fv/Fm was used as a phenotyping tool, as it reflects the effect of heat stress on maximum photochemical efficiency of photosystem...... reveal how important these identified QTLs are in terms of improving heat tolerance in wheat. Similar approach of plant phenotyping based gene discovery can be used to understand other physiological traits in plants in response to different abiotic stresses, which may lead to identification of genes...... climate, wheat is sensitive to heat stress. We need to understand how our crops will perform in these changing climatic conditions and how we can develop varieties, which are more tolerant. The PhD study focussed on understanding heat tolerance in wheat with a combined approach of plant physiology...

  4. ICRF heating in DIVA

    International Nuclear Information System (INIS)

    ICRF Heating of impurity-free tokamak plasmas has been studied in DIVA. The frequency is fixed at 25 MHz, which is a second harmonic cyclotron frequency of deuterons with a toroidal magnetic field of 16.4 kG. (1) Optimum heating conditions were investigated in varying the toroidal magnetic field B sub( t) and the proton-to-deuteron density ratio epsilon sub(p). The most favorable ion heating is observed for B sub( t) -- 18 kG and epsilon sub(p) = 5 -- 10%, which is explained by two-ion hybrid effects. (2) In heating results after improvement of the coupling structure, the ion heating efficiency is raised from 40% to almost 100%. Bulk ion temperature increased by a factor of 2.7 in application of the rf net power of 180 kW including the circuit loss. (author)

  5. Advanced heat pump

    Science.gov (United States)

    Ashley, Joseph L.; Matthews, John D.

    1989-09-01

    This patent application discloses a heat pump which includes a first packed bed of liquid desiccant for removing moisture from outside air in the heating mode of operation, and a pump for transferring the moisture laden desiccant to a second packed bed which humidifies condenser heated inside air by adding water vapor to the air. The first packed bed, by removing moisture from the outside air before it passes through the heat pump's evaporator coils, prevents frost from forming on the coils. In the cooling mode of operation the second packed bed of liquid desiccant removes water vapor from the air inside of the building. The moisture laden desiccant is then transferred to the first packed bed by a second pump where condenser heat transfers the moisture from the desiccant to outside air.

  6. Heating of domestic water by waste heat recovery from household refrigerating equipment

    Science.gov (United States)

    Reil, J.; Kaster, B.; Wegner, M.

    1982-09-01

    Heat from a 370 l deep freeze was used to heat water in a 250 l boiler. Both units were made from mass produced components. Tests show that the functions of cooling and deep freezing units can be effectively combined with one warm water boiler. The necessary expenditure for the appliance is, however, only economical with deep freezing units because with normal domestic refrigerators the amount of waste heat is too small. The economy of the unit could be considerably increased by the development of a mass produced motor compressor with a sufficiently large oil cooler to accomplish an optimum thermal insulation of the motor compressor surface area.

  7. High temperature heat exchanger studies for applications to gas turbines

    Science.gov (United States)

    Min, June Kee; Jeong, Ji Hwan; Ha, Man Yeong; Kim, Kui Soon

    2009-12-01

    Growing demand for environmentally friendly aero gas-turbine engines with lower emissions and improved specific fuel consumption can be met by incorporating heat exchangers into gas turbines. Relevant researches in such areas as the design of a heat exchanger matrix, materials selection, manufacturing technology, and optimization by a variety of researchers have been reviewed in this paper. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

  8. An experimental study of a pin-fin heat exchanger

    OpenAIRE

    Ramthun, David L.

    2003-01-01

    Approved for public release; distribution is unlimited A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins. A modular wind-tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achie...

  9. An important feature of air heat pump cycle: Heating capacity in line with heating load

    International Nuclear Information System (INIS)

    In the conventional vapor-compression heat pumps, the heating capacity and the heating load usually vary in opposite directions, which results in a mismatch of the heating capacity and the heating load at off-design conditions. Air (reversed Brayton) cycle is a potential substitute for the conventional vapor-compression cycles. This paper proved that in theory the air heat pump cycle can make the heating capacity in line with the heating load at a stable level of heating COP (coefficient of performance). A thermodynamic model for the air heat pump cycle with practical compressor and expander was developed. The optimal heating COP and the corresponding pressure ratio were derived from the model. Then the cycle performance was analytically expressed under the optimal COP conditions. The heating capacity under different operating conditions was found in line with the heating load. Comparisons between the air heat pump cycle and two typical vapor-compression heat pump cycles were numerically done for further verification. It also turned out that the energy efficiency of air heat pump is comparable to the transcritical CO2 heat pump, particularly at large temperature difference. - Highlights: • We developed a thermodynamic model for air heat pump cycle. • The optimal COP (coefficient of performance) was derived and the corresponding cycle performance was analyzed. • Comparison of air heat pump cycle and vapor-compression cycles was numerically done. • We proved air heat pump cycle can make heating capacity in line with heating load

  10. Utilization of heat pumps in the brown coal industry

    Energy Technology Data Exchange (ETDEWEB)

    Strehlau, R.

    1981-09-01

    This paper points out fields for possible energy recovery by heat pumps in the area of brown coal surface mines. It is stated that surface mine ground water from a depth of 80 m has a constant temperature of 10 to 11 C. The theoretical heat content of cooling 170,000 m/SUP/3/h of drainage water of all GDR surface mines from 10 C to 5 C is calculated to amount to 9 million MWh. Research is therefore being conducted on recovering heat from mine drainage and mine surface waters for use as space heating in buildings and installations of surface mines, which are at present electrically heated. Further sources of heat which are being examined for possible heat pump employment are heat generating plants and large surface mine machinery. Studies have been carried out by TAKRAF on determining feasibility and economic benefit of using waste heat from engine and transmission mechanisms of heavy surface mining equipment. Results of a further study on utilizing waste heat from a large transformer station show that a direct heat recovery system is definitely more efficient than employing a heat pump system, but only in the case of a transformer average load higher than 60%. (2 refs.)

  11. Local village heating. Final rapport; Landsby Naervarme. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Bojesen, C.

    2012-04-15

    Local Village Heating project relates to smaller villages which are located outside existing or planned district heating areas in Denmark. The analysis phase of Local Village Heating has shown that the concept can be the most feasible common heating system for villages that: 1. has a high building density - the buildings must be placed close together; 2. at least one large heat consumer, school, elder home or company is present in the village; 3. the number of buildings/households in the village is less than approx. 100. The analysis has shown that it is theoretical possible to establish a controlling system for the combined supplier/consumer option and an overall system for prioritizing the primary heat suppliers. A feasible Local Village Heating organisation could be a cooperative similar to other supply systems, such as common water supply and waste water cooperative. (Author)

  12. Residential heat pumps in the future Danish energy system

    DEFF Research Database (Denmark)

    Petrovic, Stefan; Karlsson, Kenneth Bernard

    2016-01-01

    for politically agreed targets which include: at least 50% of electricity consumption from wind power starting from 2020, fossil fuel free heat and power sector from 2035 and 100% renewable energy system starting from 2050. Residential heat pumps supply around 25% of total residential heating demand after 2035......Denmark is striving towards 100% renewable energy system in 2050. Residential heat pumps are expected to be a part of that system.We propose two novel approaches to improve the representation of residential heat pumps: Coefficients of performance (COPs) are modelled as dependent on air and ground...... temperature while installation of ground-source heat pumps is constrained by available ground area. In this study, TIMES-DK model is utilised to test the effects of improved modelling of residential heat pumps on the Danish energy system until 2050.The analysis of the Danish energy system was done...

  13. [Mechanism of heat transfer in various regions of human body].

    Science.gov (United States)

    Luchakov, Iu I; Nozdrachev, A D

    2009-01-01

    The processes of heat transfer in a human body were studied with the use of a mathematical model. It has been shown that only conductive or only convective heat transfer may occur in different body areas. The rate of blood-mediated heat transfer in the presence of blood circulation is many times higher than heat transfer due to temperature gradient; therefore, the convective process prevails over the conductive process. The body core contains a variety of blood vessels, and the bulk of blood concentrates there in the norm. Hence, heat transfer in it is mainly convective. In surface tissues, where the rate of blood circulation is lower and the vasculature has certain specific features, heat transfer is mainly conductive. Hence, the core and surface tissues are absolutely different body zones in terms of heat transfer.

  14. Co-operatives as heating entrepreneurs

    International Nuclear Information System (INIS)

    The objective of heating entrepreneurship functioning in the form of a co operative is to make the use of the wood chips competitive primarily through district heating of municipal centres. When compared with the conventional heating mode the reliability of chip delivery and the remuneration paid to the co-operative for attending to the running of the heating centres are considered to be the competitive advantages. The system has proven to be a working one; one indication of this is its growing application in the country. In the spring of the year 2000 there were 26 chip-based energy co-operative active in Finland. The first time that the use of bioenergy underwent a powerful rise was in the 1970s as a consequence of the oilcrises. Subsequently the enthusiasm shown to this energy form subsided. Then in the early 1990s, biofuels once again became a subject of interest mainly due to environmental issues, the restructuring of rural areas and silvicultural reasons. With the past decades' experiences forming the basis, the development needs associated with the use of bioenergy were in fresh memory and they were addressed on a wide font. Boiler technology related to solid fuels evolved rapidly and the least successful manufacturers had been eliminated by the recession. In the case of co-operative heating entrepreneurship, the commonest form neither the district heating centre nor the system of heat-transfer pipes belong to co-operative society. The co-operative is responsible only for the delivery of the fuel and for looking after the heating plant. Remuneration is generally based on the amount of energy leaving the district heating plant. Thus the heat dissipated at the heating plant is the co-operative's problem and the heat dissipated during transfer are the energy buyer's problem. The investor in the equipments usually the local municipality or an energy utility. In some cases the co-operative owns the equipments well, in which case it is correct to speak of

  15. Industrial process heat market assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bresnick, S.

    1981-12-01

    This report is designed to be a reference resource, giving a broad perspective of the potential HTGR market for industrial process heat. It is intended to serve as a briefing document for those wishing to obtain background information and also to serve as a starting point from which more detailed and refined studies may be undertaken. In doing so, the report presents a qualitative and quantitative description of the industrial process heat market in the US, provides a summary discussion of cogeneration experience to date, and outlines the existing institutional and financial framework for cogeneration. The intent is to give the reader an understanding of the current situation and experience in this area. The cogeneration area in particular is an evolving one because of regulations and tax laws, which are still in the process of being developed and interpreted. The report presents the latest developments in regulatory and legislative activities which are associated with that technology. Finally, the report presents a brief description of the three HTGR systems under study during the current fiscal year and describes the specific market characteristics which each application is designed to serve.

  16. Heat transfer between graphene and amorphous SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Persson, B N J; Ueba, H [Division of Nanotechnology and New Functional Material Science, Graduate School of Science and Engineering, University of Toyama, Toyama (Japan)

    2010-11-24

    We study the heat transfer between graphene and amorphous SiO{sub 2}. We include both the heat transfer from the area of real contact, and between the surfaces in the non-contact region. We consider the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies, and the heat transfer by the gas in the non-contact region. We find that the dominant contribution to the heat transfer results from the area of real contact, and the calculated value of the heat transfer coefficient is in good agreement with the value deduced from experimental data. (fast track communication)

  17. Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, Anoop [Terrafore Inc.

    2013-08-14

    A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during

  18. Heat pipes. Citations from the NTIS data base

    Science.gov (United States)

    Reed, W. E.

    1980-04-01

    Theory, design, fabrication, testing, and operation of heat pipes are presented in these Federally sponsored research reports. Applications are described in the areas of heating and air conditioning, power generation, electronics cooling, spacecraft, nuclear reactors, cooling engines, and thermodynamics. This updated bibliography contains 70 abstracts, all of which are new entries to the previous edition.

  19. The porosity in a fluidized bed heat transfer model

    NARCIS (Netherlands)

    Visser, G.; Valk, M.

    1993-01-01

    A mathematical model of heat transfer between a fluidized bed and an immersed surface and a model of gas flow and porosity, both recently published, were combined and further modified in the area of low velocities where the particle convective component of heat transfer is low or neglectable. Experi

  20. Refrigeration, Heating & Air Conditioning. Post Secondary Curriculum Guide.

    Science.gov (United States)

    Garrison, Joe C.; And Others

    This curriculum guide was designed for use in postsecondary refrigeration, heating and air conditioning education programs in Georgia. Its purpose is to provide for the development of entry level skills in refrigeration, heating, and air conditioning in the areas of air conditioning knowledge, theoretical structure, tool usage, diagnostic ability,…

  1. A Geographic Method for High Resolution Spatial Heat Planning

    DEFF Research Database (Denmark)

    Nielsen, Steffen

    2014-01-01

    In many countries, district heating (DH) covers a large share of the heat market. In these countries, the best locations for DH systems have already been found. Therefore, the challenge for these countries is to find expansion potentials for existing DH. The expansion to less ideal areas requires...

  2. Experimental research on heat transfer of pulsating heat pipe

    Science.gov (United States)

    Li, Jia; Yan, Li

    2008-06-01

    Experimental research was conducted to understand heat transfer characteristic of pulsating heat pipe in this paper, and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appears in top heating condition. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred from bulk flow to semi-annular flow and annular flow, and the performance of heat transfer is improved for down heating case. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

  3. Experimental research on heat transfer of pulsating heat pipe

    Institute of Scientific and Technical Information of China (English)

    LI Jia; Yan Li

    2008-01-01

    Experimental research was conducted to understand heat transfer characteristic of pulsating heat pipe in this paper,and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appears in top heating condition. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred from bulk flow to semi-annular flow and annular flow, and the performance of heat transfer is improved for down heating case. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

  4. 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.

  5. Heat pipe dynamic behavior

    Science.gov (United States)

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

    1988-01-01

    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  6. Coral Reef Watch, Degree Heating Weeks, 50 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Coral Reef Watch distributes Degree Heating Week products using a combination of the POES AVHRR Global Area Coverage data, and data from a climatological...

  7. Heat Island Mitigation Measures in Response to Climate Change Impacts

    Science.gov (United States)

    Quattrochi, Dale a.; Estes, Maurice, Jr.; Crosson, William; Al-Hamdan, Mohammad

    2010-01-01

    This slide presentation examines the effect of cities, the accompanying heat island effect, and other impacts that urbanization has had on the environment. Various satellite views of several urban areas are shown.

  8. Solar heating and cooling technical data and systems analysis

    Science.gov (United States)

    Christensen, D. L.

    1977-01-01

    The research activities described herein were concentrated on the areas of economics, heating and cooling systems, architectural design, materials characteristics, climatic conditions, educational information packages, and evaluation of solar energy systems and components.

  9. GIS Based Analysis of future district heating potential in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    2012-01-01

    The physical placement of buildings is important when determining the future potential for district heating (DH). Good locations for DH are mainly determined by having a large heat demand within a certain area combined with an access to local resources. In Denmark, the placement of buildings and...... finding the heat production cost within these areas, and adding transmission and distribution costs, the economic feasibility of supplying areas with DH is found. The result of the analysis is that the DH potential differs from area to area. In many areas it is economically feasible to expand DH, while in...... others production costs and grid losses should be reduced for DH expansions to be feasible. Including transmission and distribution costs into the calculation, gives an idea about where the boundaries for DH are. These boundaries are not static, but changes under different conditions....

  10. Electrohydrodynamic heat pipes.

    Science.gov (United States)

    Jones, T. B.

    1973-01-01

    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  11. Elementary heat transfer analysis

    CERN Document Server

    Whitaker, Stephen; Hartnett, James P

    1976-01-01

    Elementary Heat Transfer Analysis provides information pertinent to the fundamental aspects of the nature of transient heat conduction. This book presents a thorough understanding of the thermal energy equation and its application to boundary layer flows and confined and unconfined turbulent flows. Organized into nine chapters, this book begins with an overview of the use of heat transfer coefficients in formulating the flux condition at phase interface. This text then explains the specification as well as application of flux boundary conditions. Other chapters consider a derivation of the tra

  12. Heat pipes - Thermal diodes

    Science.gov (United States)

    Aptekar, B. F.; Baum, J. M.; Ivanovskii, M. N.; Kolgotin, F. F.; Serbin, V. I.

    The performance concept and peculiarities of the new type of thermal diode with the trap and with the wick breakage are dealt with in the report. The experimental data were obtained and analysed for the working fluid mass and the volume of the liquid in the wick on the forward-mode limiting heat transfer. The flow rate pulsation of the working fluid in the wick was observed visually on the setup with the transparent wall. The quantitative difference on the data on the investigated thermal diode and on the identical heat pipes without the wick breakage is found experimentally concerning the forward-mode limiting heat transfer.

  13. Episodic coronal heating

    International Nuclear Information System (INIS)

    A study is made of the observational consequences of the hypothesis that there is no steady coronal heating, the solar corona instead being heated episodically, such that each short burst of heating is followed by a long period of radiative cooling. The form of the resulting contribution to the differential emission measure (DEM), and to a convenient related function (the differential energy flux, DEF) is calculated. Observational data for the quiet solar atmosphere indicate that the upper branch of the DEM, corresponding to temperatures above 100,000 K, can be interpreted in terms of episodic energy injection at coronal temperatures. 22 refs

  14. Heat pump planning handbook

    CERN Document Server

    Bonin, Jürgen

    2015-01-01

    The Heat Pump Planning Handbook contains practical information and guidance on the design, planning and selection of heat pump systems, allowing engineers, designers, architects and construction specialists to compare a number of different systems and options. Including detailed descriptions of components and their functions and reflecting the current state of technology this guide contains sample tasks and solutions as well as new model calculations and planning evaluations. Also economic factors and alternative energy sources are covered, which are essential at a time of rising heat costs. T

  15. Waste heat recovery system

    International Nuclear Information System (INIS)

    Full text: The Konzen in-house designed anaerobic digester system for the POME (Palm Oil Mill Effluent) treatment process is one of the registered Clean Development Mechanism (CDM) projects in Malaysia. It is an organic wastewater treatment process which achieves excellent co-benefits objectives through the prevention of water pollution and reduction of greenhouse gas emissions, which is estimated to be 40,000 to 50,000 t-CO2 per year. The anaerobic digester was designed in mesophile mode with temperature ranging from 37 degree Celsius to 45 degree Celsius. A microorganisms growth is optimum under moderately warm temperature conditions. The operating temperature of the anaerobic digester needs to be maintained constantly. There are two waste heat recovery systems designed to make the treatment process self-sustaining. The heat recovered will be utilised as a clean energy source to heat up the anaerobic digester indirectly. The first design for the waste heat recovery system utilises heat generated from the flue gas of the biogas flaring system. A stainless steel water tank with an internal water layer is installed at the top level of the flare stack. The circulating water is heated by the methane enriched biogas combustion process. The second design utilizes heat generated during the compression process for the biogas compressor operation. The compressed biogas needs to be cooled before being recycled back into the digester tank for mixing purposes. Both the waste heat recovery systems use a design which applies a common water circulation loop and hot water tank to effectively become a closed loop. The hot water tank will perform both storage and temperature buffer functions. The hot water is then used to heat up recycled sludge from 30 degree Celsius to 45 degree Celsius with the maximum temperature setting at 50 degree Celsius. The recycled sludge line temperature will be measured and monitored by a temperature sensor and transmitter, which will activate the

  16. Episodic coronal heating

    Science.gov (United States)

    Sturrock, P. A.; Dixon, W. W.; Klimchuk, J. A.; Antiochos, S. K.

    1990-01-01

    A study is made of the observational consequences of the hypothesis that there is no steady coronal heating, the solar corona instead being heated episodically, such that each short burst of heating is followed by a long period of radiative cooling. The form of the resulting contribution to the differential emission measure (DEM), and to a convenient related function (the differential energy flux, DEF) is calculated. Observational data for the quiet solar atmosphere indicate that the upper branch of the DEM, corresponding to temperatures above 100,000 K, can be interpreted in terms of episodic energy injection at coronal temperatures.

  17. Heat exchanger design handbook

    CERN Document Server

    Thulukkanam, Kuppan

    2013-01-01

    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  18. Probe tip heating assembly

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  19. Heat treatment furnace

    Science.gov (United States)

    Seals, Roland D; Parrott, Jeffrey G; DeMint, Paul D; Finney, Kevin R; Blue, Charles T

    2014-10-21

    A furnace heats through both infrared radiation and convective air utilizing an infrared/purge gas design that enables improved temperature control to enable more uniform treatment of workpieces. The furnace utilizes lamps, the electrical end connections of which are located in an enclosure outside the furnace chamber, with the lamps extending into the furnace chamber through openings in the wall of the chamber. The enclosure is purged with gas, which gas flows from the enclosure into the furnace chamber via the openings in the wall of the chamber so that the gas flows above and around the lamps and is heated to form a convective mechanism in heating parts.

  20. Heat conduction in nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Wang Liqiu [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)], E-mail: lqwang@hkucc.hku.hk; Wei Xiaohao [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)

    2009-03-15

    We show that macroscale heat conduction in nanofluids is of a dual-phase-lagging type rather than the Fourier type. This leads to models for effective thermal capacity, conductivity and diffusivity of nanofluids and reveals even more anomalous thermal behavior of nanofluids than those reported in the literature. Due to the coupled conduction of the two phases, thermal waves and possibly resonance may appear in nanofluid heat conduction. Such waves and resonance are responsible for the extraordinary conductivity enhancement. The analysis and result are also valid for heat conduction in two-phase systems.

  1. Microscale surface modifications for heat transfer enhancement.

    Science.gov (United States)

    Bostanci, Huseyin; Singh, Virendra; Kizito, John P; Rini, Daniel P; Seal, Sudipta; Chow, Louis C

    2013-10-01

    In this experimental study, two surface modification techniques were investigated for their effect on heat transfer enhancement. One of the methods employed the particle (grit) blasting to create microscale indentations, while the other used plasma spray coating to create microscale protrusions on Al 6061 (aluminum alloy 6061) samples. The test surfaces were characterized using scanning electron microscopy (SEM) and confocal scanning laser microscopy. Because of the surface modifications, the actual surface area was increased up to 2.8× compared to the projected base area, and the arithmetic mean roughness value (Ra) was determined to vary from 0.3 μm for the reference smooth surface to 19.5 μm for the modified surfaces. Selected samples with modified surfaces along with the reference smooth surface were then evaluated for their heat transfer performance in spray cooling tests. The cooling system had vapor-atomizing nozzles and used anhydrous ammonia as the coolant in order to achieve heat fluxes up to 500 W/cm(2) representing a thermal management setting for high power systems. Experimental results showed that the microscale surface modifications enhanced heat transfer coefficients up to 76% at 500 W/cm(2) compared to the smooth surface and demonstrated the benefits of these practical surface modification techniques to enhance two-phase heat transfer process.

  2. Counterflow Regolith Heat Exchanger Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  3. Heat Stress in Older Adults

    Science.gov (United States)

    ... Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Heat Stress in Older Adults Recommend on Facebook Tweet Share ... What You Can Do for Someone With Heat Stress If you see any signs of severe heat ...

  4. Split-system solar cooker with heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, A.M.A.; Taha, M.M.A.; Mannaa, A.; Akyurt, M.

    1986-01-01

    A split-system solar cooker is described which has its flat-plate collector outdoors and the cooking chamber inside the kitchen, with heat pipes transferring the energy between the two. Test results are discussed, and areas of possible improvement are indicated. The results of a series of tests conducted to ascertain the most suitable heat transfer arrangement in the cooking chamber are presented. Recommendations are made for further areas of improvement.

  5. Some comments on air source heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Haukaas, H.T. (Norges tekniska hoegskola, Trondheim (Norway)). Institutt for kuldeteknikk

    1982-02-01

    Some vital conditions regarding air/water heat pumps are analyzed by use of computer simulators of a middle sized heat pump system. Heat pumps, and specially air source units, should always be used in combination with conventional heating equipment for peak load supply. (Bivalent systems). The economic optimum heat pump capacity compared to system design load is strongly related to the climate. At typical coastal conditions a ratio of 60-70 per cent is found favourable, while 40-50 per cent will be the correct choice for Norwegian inland area. Analysis of the evaporator shows that it should be designed for 120-130 W/m/sup 2/ specific load and 2-2.2 m/s inlet air velocity, which is well below common practice in designing standard air coolers. The condenser LMTD (logaritmic mean temperature difference) should be chosen about 4 degrees C, while the corresponding 'sellers optimum' is calculated to app. 8.5 degrees C. The difference in total heating costs between systems fully designed according to 'sellers optimum' and 'buyers optimum' respectively is found to be about 0.01 Nkr/kWh.

  6. Advanced heat pump cycle

    Energy Technology Data Exchange (ETDEWEB)

    Groll, E.A.; Radermacher, R.

    1993-07-01

    The desorption and absorption process of a vapor compression heat pump with a solution circuit (VCHSC) proceeds at gliding temperature intervals, which can be adjusted over a wide range. In case that the gliding temperature intervals in the desorber and the absorber overlap, a modification of the VCHSC employing a desorber/absorber heat exchange (DAHX) can be introduced, which results in an extreme reduction of the pressure ratio. Although the DAHX-cycle has features of a two-stage cycle, it still requires only one solution pump, one separator and one compressor. Such a cycle for the working pair ammonia/water is built in the Energy Laboratory of the Center for Environmental Energy Engineering at the University of Maryland. The experimental results obtained with the research plant are discussed and compared to those calculated with a simulation program. The possible temperature lift between heat source and heat sink depending on the achievable COP are presented.

  7. Condensation heat transfer

    Science.gov (United States)

    Rose, J. W.

    The paper gives a brief description of some of the better understood aspects of condensation heat transfer and includes discussion of the liquid-vapour interface, natural and forced convection laminar film condensation and dropwise condensation.

  8. Analytical heat transfer

    CERN Document Server

    Han, Je-Chin

    2012-01-01

    … it will complete my library … [and] complement the existing literature on heat transfer. It will be of value for both graduate students and faculty members.-Bengt Sunden, Lund University, Sweden

  9. Policies for Renewable Heat

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    This paper builds on IEA publications, Deploying Renewables, Principles for Effective Policies and Deploying Renewables, Best and Future Policy Practice, that discuss the 'integrated policy approach,' whereby renewable energy technologies require different support policies at different stages of their maturity pathways. The paper discusses how the integrated policy approach applies to renewable heat. It attempts to provide guidance for policy-makers on renewable heat throughout the different phases of the policy lifecycle, allowing for the specific challenges of renewable heat and needs of the many stakeholders involved. Stimulating a market for heat involves challenges that are different and, often, more difficult to overcome than in the electricity and transport sectors.

  10. Estimation of the Distribution of Global Anthropogenic Heat Flux

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The radiance lights data in 2006 from the National Oceanic and Atmospheric Administration Air Force Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) and authoritative energy data distributed by the United State Energy Information Administration were applied to estimate the global distribution of anthropogenic heat flux.A strong linear relationship was found to exist between the anthropogenic heat flux and the DMSP/OLS radiance data.On a global scale,the average value of anthropogenic heat flux is approximately 0.03 W m 2 and 0.10 W m 2 for global land area.The results indicate that global anthropogenic heat flux was geographically concentrated and distributed,fundamentally correlating to the economical activities.The anthropogenic heat flux concentrated in the economically developed areas including East Asia,Europe,and eastern North America.The anthropogenic heat flux in the concentrated regions,including the northeastern United States,Central Europe,United Kingdom,Japan,India,and East and South China is much larger than global average level,reaching a large enough value that could affect regional climate.In the center of the concentrated area,the anthropogenic heat flux density may exceed 100 W m 2,according to the results of the model.In developing areas,including South America,Central and North China,India,East Europe,and Middle East,the anthropogenic heat flux can reach a level of more than 10 W m 2 ;however,the anthropogenic heat flux in a vast area,including Africa,Central and North Asia,and South America,is low.With the development of global economy and urban agglomerations,the effect on climate of anthropogenic heat is essential for the research of climate change.

  11. DEVELOPING LOW TEMPERATURE SOURCE LOCAL HEATING FOR PIGLETS

    Directory of Open Access Journals (Sweden)

    Chus R. V.

    2015-04-01

    Full Text Available During the research, we have developed a low-temperature zonal heating panels with an infrared emitter to create a local microclimate for piglets in the suckling period. This heater is lightweight and durable frame in the form of an inverted box size 400 mm x 1800 mm, attached to the wall of the building swivel. Top frame mounted thermostat is connected to a temperature sensor mounted directly on a metal plate with a thickness of 1 mm, painted in black color. In the upper part of the inner carcass layer is a light insulating material, which is located directly under the low-temperature heat source is electric. Study of the optimal size of the heating panel revealed that in view of the limitations associated with the area of the machine and biological characteristics of the optimum size of the sow for 11 piglets are: width – 400 mm; length – 1500 mm (at ventral position and 1800 mm (lateral position. Comparison of different heating sources for piglets revealed that the use of infrared lamps enables newborn piglets seating area by 55.6%, while in 28 days – by 88.9%. Infrared lamps can not completely meet the recommended specifications as to ensure a more intense heat lamp to be lowered towards the floor surface, which leads to a reduction in the useful area heated. Using as a source of local heating mats and low-temperature panels satisfies pigs in the area of the den in the early suckling period at 138.9 and 200.0%, to weaning, respectively – by 48.5 and 65.5%. Thus, we have developed a low-temperature heating panels contributed to a more uniform distribution of heat in a recreation area of suckling piglets and to provide a comfortable environment at temperatures of 2-3 C lower in comparison with other methods of heating

  12. Thermal radiation heat transfer

    CERN Document Server

    Howell, John R; Siegel, Robert

    2016-01-01

    Further expanding on the changes made to the fifth edition, Thermal Radiation Heat Transfer, 6th Edition continues to highlight the relevance of thermal radiative transfer and focus on concepts that develop the radiative transfer equation (RTE). The book explains the fundamentals of radiative transfer, introduces the energy and radiative transfer equations, covers a variety of approaches used to gauge radiative heat exchange between different surfaces and structures, and provides solution techniques for solving the RTE.

  13. Superradiant Quantum Heat Engine

    OpenAIRE

    Hardal, Ali Ü. C.; Müstecaplıoğlu, Özgür E.

    2015-01-01

    Scientific Reports | 5:12953 | DOI: 10.1038/srep12953 1 www.nature.com/scientificreports Superradiant Quantum Heat Engine Ali Ü. C. Hardal & Özgür E. Müstecaplıoğlu Quantum physics revolutionized classical disciplines of mechanics, statistical physics, and electrodynamics. One branch of scientific knowledge however seems untouched: thermodynamics. Major motivation behind thermodynamics is to develop eficient heat engines. Technology has a trend to miniaturize engines, ...

  14. Heat Switches for ADRs

    Science.gov (United States)

    DiPirro, M. J.; Shirron, P. J.

    2014-01-01

    Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

  15. Geodesics in Heat

    OpenAIRE

    Crane, Keenan; Weischedel, Clarisse; Wardetzky, Max

    2012-01-01

    We introduce the heat method for computing the shortest geodesic distance to a specified subset (e.g., point or curve) of a given domain. The heat method is robust, efficient, and simple to implement since it is based on solving a pair of standard linear elliptic problems. The method represents a significant breakthrough in the practical computation of distance on a wide variety of geometric domains, since the resulting linear systems can be prefactored once and subsequently solved in near-li...

  16. Beam induced heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Baudrenghien, P; Bracco, C; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Esteban Mueller, J; Gentini, L; Goddar, B; Grudiev, A; Henrist, B; Jones, R; Lanza, G; Lari, L; Mastoridis, T; Métral, E; Mounet, N; Nougaret, J L; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Sapinski, M; Shaposhinkova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wollmann, D

    2012-01-01

    In 2011, the rapid increase of the luminosity performance of LHC came at the expense of increased temperature and pressure readings on several near-beam LHC equipments. In some cases, this beam induced heating was suspected to cause beam dumps and even degradation of the equipment. This contribution aims at gathering the observations of beam induced heating due to beam coupling impedance, their current level of understanding and possible actions that could be implemented during the winter stop 2011-2012.

  17. Heat Pipe Systems

    Science.gov (United States)

    1988-01-01

    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

  18. Demand modelling for central heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    Most researchers in the field of heat demand estimation have focussed on explaning the load for a given plant based on rather few measurements. This approach is simply the only one adaptable with the very limited data material and limited computer power. This way of dealing with the subject is here called the top-down approach, due to the fact that one tries to explain the load from the overall data. The results of such efforts are discussed in the report, leading to inspiration for own work. Also the significance of the findings to the causes for given heat loads are discussed and summarised. Contrary to the top-down approach applied in literature, a here-called bottom-up approach is applied in this work, describing the causes of a given partial load in detail and combining them to explain the total load for the system. Three partial load 'components' are discussed: 1) Space heating. 2) Hot-Water Consumption. 3) Heat losses in pipe networks. The report is aimed at giving an introduction to these subjects, but at the same time at collecting the previous work done by the author. Space heating is shortly discussed and loads are generated by an advanced simulation model. A hot water consumption model is presented and heat loads, generated by this model, utilised in the overall work. Heat loads due to heat losses in district heating a given a high priority in the current work. Hence a detailed presentation and overview of the subject is given to solar heating experts normally not dealing with district heating. Based on the 'partial' loads generated by the above-mentioned method, an overall load model is built in the computer simulation environment TRNSYS. The final tool is then employed for the generation of time series for heat demand, representing a district heating area. The results are compared to alternative methods for the generation of heat demand profiles. Results form this comparison will be presented. Computerised modelling of systems

  19. Optimal design of the separate type heat pipe heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YU Zi-tao; HU Ya-cai; CEN Ke-fa

    2005-01-01

    Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations have to be carried out separately, which makes it very complicated. In this work, the ε-NTU (effectiveness-Number of Transfer Units) method was applied for optimization analysis of single- or multi-level separate type heat pipe heat exchangers. An optimizing formula for single-level separate type heat pipe heat exchangers was obtained. The optimizing principles of effectiveness-NTU and heat transfer rate by the equal distribution method for multi-level separate type heat pipe heat exchanger are presented. The design of separate type heat pipe heat exchangers by the optimizing method is more convenient and faster than by the traditional method.

  20. 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.

  1. Heat Pipe Solar Receiver for Oxygen Production of Lunar Regolith

    Science.gov (United States)

    Hartenstine, John R.; Anderson, William G.; Walker, Kara L.; Ellis, Michael C.

    2009-03-01

    A heat pipe solar receiver operating in the 1050° C range is proposed for use in the hydrogen reduction process for the extraction of oxygen from the lunar soil. The heat pipe solar receiver is designed to accept, isothermalize and transfer solar thermal energy to reactors for oxygen production. This increases the available area for heat transfer, and increases throughput and efficiency. The heat pipe uses sodium as the working fluid, and Haynes 230 as the heat pipe envelope material. Initial design requirements have been established for the heat pipe solar receiver design based on information from the NASA In-Situ Resource Utilization (ISRU) program. Multiple heat pipe solar receiver designs were evaluated based on thermal performance, temperature uniformity, and integration with the solar concentrator and the regolith reactor(s). Two designs were selected based on these criteria: an annular heat pipe contained within the regolith reactor and an annular heat pipe with a remote location for the reactor. Additional design concepts have been developed that would use a single concentrator with a single solar receiver to supply and regulate power to multiple reactors. These designs use variable conductance or pressure controlled heat pipes for passive power distribution management between reactors. Following the design study, a demonstration heat pipe solar receiver was fabricated and tested. Test results demonstrated near uniform temperature on the outer surface of the pipe, which will ultimately be in contact with the regolith reactor.

  2. Flat plate electrohydrodynamic heat pipe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Loehrke, R.I.; Sebits, D.R.

    1975-07-01

    Performance capabilities of electrohydrodynamic (EHD) flat heat pipes were investigated using Freon 113 and Freon 11 as working fluids. All of the pipes employed straight rod electrodes to form axial liquid flow channels and tranverse grooves for capillary surface wetting. Results show: (1) the EHD pipe will prime under load; (2) voltage controlled conductance can be achieved by varying the active area of the evaporator; and (3) the average evaporator conductances measured in these experiments were consistent with those obtained in other experiments with heat pipes of similar surface geometry using the same or similar working fluids.

  3. Conducting the Heat

    Science.gov (United States)

    2003-01-01

    Heat conduction plays an important role in the efficiency and life span of electronic components. To keep electronic components running efficiently and at a proper temperature, thermal management systems transfer heat generated from the components to thermal surfaces such as heat sinks, heat pipes, radiators, or heat spreaders. Thermal surfaces absorb the heat from the electrical components and dissipate it into the environment, preventing overheating. To ensure the best contact between electrical components and thermal surfaces, thermal interface materials are applied. In addition to having high conductivity, ideal thermal interface materials should be compliant to conform to the components, increasing the surface contact. While many different types of interface materials exist for varying purposes, Energy Science Laboratories, Inc. (ESLI), of San Diego, California, proposed using carbon velvets as thermal interface materials for general aerospace and electronics applications. NASA s Johnson Space Center granted ESLI a Small Business Innovation Research (SBIR) contract to develop thermal interface materials that are lightweight and compliant, and demonstrate high thermal conductance even for nonflat surfaces. Through Phase II SBIR work, ESLI created Vel-Therm for the commercial market. Vel-Therm is a soft, carbon fiber velvet consisting of numerous high thermal conductivity carbon fibers anchored in a thin layer of adhesive. The velvets are fabricated by precision cutting continuous carbon fiber tows and electrostatically flocking the fibers into uncured adhesive, using proprietary techniques.

  4. Magnetic heat pump design

    Science.gov (United States)

    Kirol, L. D.; Dacus, M. W.

    1988-03-01

    Heat pumps utilizing the magnetocaloric effect offer a potentially attractive alternative to conventional heat pumps and refrigerators. Many physical configurations of magnetic heat pumps are possible. Major classes include those requiring electrical energy input and those with mechanical energy input. Mechanical energy is used to move magnets, working material, or magnetic shielding. Each type of mechanical magnetic heat pump can be built in a rotary (recuperative) or reciprocal (regenerative) configuration. Machines with electrical energy input utilize modulation of the magnetic field to cause working material to execute the desired thermodynamic cycle, and can also be recuperative or regenerative. Recuperative rotary heat pumps in which working material is moved past stationary magnets is the preferred configuration. Regenerative devices suffer performance degradation from temperature change of regenerator material and mixing and conduction in the regenerator. Field modulated cycles are not practical due to ac losses in superconducting magnets. Development of methods for recuperator fluid pumping is the major challenge in design of rotary recuperative devices. Several pumping options are presented, and the design of a bench scale heat pump described.

  5. Critical heat flux thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Collado, F.J. E-mail: fjk@posta.unizar.es

    2002-11-01

    Convective boiling in subcooled water flowing through a heated channel is essential in many engineering applications where high heat flux need to be accommodated, such as in the divertor plates of fusion reactors. There are many available correlations for predicting heat transfer in the individual regimes of the empirical Nukiyama boiling curve, although unfortunately there is no physical fundamentals of such curve. Recently, the author has shown that the classical entropy balance could contain key information about boiling heat transfer. So, it was found that the average thermal gap in the heated channel (the wall temperature minus the average temperature of the coolant fluid) was strongly correlated with the efficiency of a theoretical reversible engine placed in this thermal gap. In this work and from the new proposed correlation, a new expression of the wall temperature in function of the average fluid temperature is derived and successfully checked against experimental data from General Electric. This expression suggests a new and simple definition of the critical heat flux (CHF), a key parameter of the thermal-hydraulic design of fusion reactors. Finally, based on the new definition, the CHF trends are commented.

  6. Advective Heat Transport in an Unconfined Aquifer Induced by the Field Injection of an Open-Loop Groundwater Heat Pump

    OpenAIRE

    Stefano L. Russo; Glenda Taddia

    2010-01-01

    Problem statement: The increasing diffusion of low-enthalpy geothermal open-loop Groundwater Heat Pumps (GWHP) providing buildings air conditioning requires a careful assessment of the overall effects on groundwater system, especially in the urban areas. The impact on the groundwater temperature in the surrounding area of the re-injection well is directly linked to the aquifer properties. Physical processes affecting heat transport within an aquifer include advection (or convection) and hydro...

  7. Heat illness--a review of military experience (Part 1).

    Science.gov (United States)

    Bricknell, M C

    1995-10-01

    This paper is the first part of a two part review of the published literature reporting the military experience of heat illness. It summarises current concepts of the mechanisms for the development of heat illness. The reports of heat illness in the military medical literature from pre-World War 1 to the end of World War 2 are discussed. The second part will consider reports from the end of the Second World War to the present day. Epidemiological evidence for the factors causing heat illness will be summarised and finally the current areas of uncertainty will be identified with proposals for future research.

  8. Barents Sea heat – transport, storage and surface fluxes

    Directory of Open Access Journals (Sweden)

    Ø. Skagseth

    2009-07-01

    Full Text Available Sensitivity of the Barents Sea to variation in ocean heat transport and surface fluxes is explored using a 1-D column model. Mean monthly ocean transport and atmospheric forcing are synthesised and force model results that reproduce the observed winter convection and surface warming and freshening well. Model results are compared to existing estimates of the ocean to air heat fluxes and horizontally averaged profiles for the southern and northern Barents Sea. Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production. The northern Barents Sea, the major part of the area, receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss in the north, the balance is achieved by long wave loss removing most of the solar heating, and the model also suggests a positive sensible heat gain. During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. Despite large changes the Barents Sea heat loss remains robust, the temperature adjusts, and the yearly cycle remains. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport probably leads to a spreading of warm water further north.

  9. 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

  10. Utilization of heat pipes for transfer heat from the flue gas into the heat transfer medium

    Directory of Open Access Journals (Sweden)

    Lenhard Richard

    2014-03-01

    Full Text Available The contribution is listed possible application of heat pipes in systems for obtaining heat from flue gas of small heat sources. It is also stated in the contribution design an experimental device on which to study the impact of fill (the quantity, type of load at various temperature parameters (temperature heating and cooling thermal power transferred to the heat pipe. Is listed measurement methodology using heat pipes designed experimental facility, measurement results and analysis of the results obtained.

  11. Heat transfer interface between a high temperature heat source and a heat sink

    Energy Technology Data Exchange (ETDEWEB)

    du Pre, F.K.; Jaspers, H.A.

    1977-10-11

    A heat-transfer interface between and separating a high temperature heat source and a heat sink is formed by the adjacent walls of the heat source and heat sink with a thin gap between these walls and helium gas sealed in the gap, the walls preferably defining concentric hemispheres; this interface being particularly feasible as separable walls of the heater portion of a Stirling engine and a heat source.

  12. Quantitative Study of Green Area for Climate Sensitive Terraced Housing Area Design in Malaysia

    International Nuclear Information System (INIS)

    Neighbourhood plays a significant role in peoples' daily lives. Nowadays, terraced housing is common in Malaysia, and green areas in the neighborhood are not used to their maximum. The aim of the research is to quantify the types of green area that are most efficient for cooling the environment for thermal comfort and mitigation of Urban Heat Island. Spatial and environmental inputs are manipulated for the simulation using Geographic Information System (GIS) integrated with computational microclimate simulation. The outcome of this research is a climate sensitive housing environment model framework on the green area to solve the problem of Urban Heat Island

  13. Quantitative Study of Green Area for Climate Sensitive Terraced Housing Area Design in Malaysia

    Science.gov (United States)

    Yeo, O. T. S.; Saito, K.; Said, I.

    2014-02-01

    Neighbourhood plays a significant role in peoples' daily lives. Nowadays, terraced housing is common in Malaysia, and green areas in the neighborhood are not used to their maximum. The aim of the research is to quantify the types of green area that are most efficient for cooling the environment for thermal comfort and mitigation of Urban Heat Island. Spatial and environmental inputs are manipulated for the simulation using Geographic Information System (GIS) integrated with computational microclimate simulation. The outcome of this research is a climate sensitive housing environment model framework on the green area to solve the problem of Urban Heat Island.

  14. Optimization Studies of Tank-Volume-to-Collector-Area Ratio for South-Facing Flat-Plate Solar Water Heating System Used in Yunnan Province%云南南向平板太阳能热水系统水量配比特性研究

    Institute of Scientific and Technical Information of China (English)

    胡粉娥; 魏生贤

    2016-01-01

    基于平板型集热器日均能量输出模型,建立了太阳能热水系统水箱水量与集热器面积的配比模型.以云南省10个城市的典型气象数据为例,利用所建模型对太阳能热水系统的水量配比进行了计算.为便于实际应用,给出了水箱终温为60℃时各城市各季节和全年使用太阳能热水系统水量配比与倾角间相关系数大于0.999的数学关系式.进一步研究发现,这10个城市春季、夏季、秋季、冬季和全年使用太阳能热水系统集热器的最佳倾角及其对应的水量配比分别在5~15°,0~0°,29~38°,43~50°,20~30°和50~62,44~60,43~56,44~58,46~56 kg/m2之间.依据供热目的的不同,可利用该研究结果对太阳能热水系统进行优化设计.%The model for discussing the tank‐volume‐to‐collector‐area ratio (the ratio is abbreviated as MAR) for south‐facing flat‐plate solar water heating system was established based on the energy output model of the flat‐plate solar collector .The MARs were calculated by using the typical meteorological data of ten cities in Yunnan Province .The final water temperature in the storage tank is 60 ℃ in the calculation process .To facilitate engineering applications ,the quadratic fit relations between the MARs and the tilt angles of the solar collector have been obtained with high correlation coefficients (R2 > 0.999) .Further discussions found that the optimal tilt angles and the corresponding MARs for spring ,summer ,autumn , winter and year‐round operation of the solar water heating system are respectively in 5~15° ,0~0° ,29~38° ,43~50° ,20~30° ,50~62 kg/m2 ,44~60 kg/m2 ,43~56 kg/m2 ,44~58 kg/m2 and 46~56 kg/m2 . Depending on the purpose and requirement of heating ,the seasonal or year‐round solar hot water systems can be optimized and designed by using the key results from this paper .

  15. Expansion of district heating in Munich; Fernwaermeausbau in Muenchen

    Energy Technology Data Exchange (ETDEWEB)

    Prein, Thomas [SWM Services GmbH, Muenchen (Germany)

    2012-07-01

    For some time the population of Munich (Federal Republic of Germany) is growing. However, the residential areas within the existing boundaries of the city is limited. The demand for living area is very high and results in a compact building construction. In the western region of Munich the new district Freiham is developed for about 20,000 people, commerce and trade. The public utility Munich have decided to realize the heat supply of this new district by means of district heating. This requires not only a new district heating network, but also a new power plant.

  16. Heat exchanger device and method for heat removal or transfer

    Science.gov (United States)

    Koplow, Jeffrey P

    2013-12-10

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  17. Numerical research of heat transfer in gas heat exchanger

    OpenAIRE

    Khomutov Eugene O.; Gil Andrey V.

    2015-01-01

    The article presents a numerical study of heat and mass transfer based on the finite volume method. Researched by installing a tubular heat exchanger for heating of natural gas. The results according to changes in temperature of the natural gas depend on the initial temperature of the heating flow. The results can be used in the analysis of further effective combustion.

  18. Advanced heat removal system with porous media for electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Mahalle, A.M. [Sant Gadge Baba Amravati Univ., Amravati (India). Dept. of Mechanical Engineering; Jajoo, B.N. [Sant Gadge Baba Amravati Univ., Amravati (India). College of Engineering and Technology

    2007-07-01

    High porosity metal foams are primarily utilized in aerospace applications, although there use has been widened to include cooling in electronic packaging. They are good for high heat dissipation and other important applications have been found taking advantages of the thermal properties of the metal foam, including compact heat exchangers for airborne equipment; regenerative and dissipative air cooled condenser towers; and compact heat sinks for electronic power. Metal foam heat exchangers are efficient, compact and lightweight because of their low relative density, open porosity and high thermal conductivity of the cell edges, as well as the large accessible surface area per unit volume, and the ability to mix the cooling fluid. This paper presented the results of an investigation whose purpose was to prove the foam metal is a high heat dissipater using different heat inputs. The paper discussed the experimental methodology and described the metal foam sample used in the experiment. The heat transfer coefficient was increased as the velocity increased. The Reynolds number and Nusselt number was increased to increasing velocity. It was concluded that heat transfer from foam was primarily governed by total heat transfer area of the foam rather than the thermal conductivity. 16 refs., 14 figs.

  19. Heat Pump with Two Heat Sources on Different Temperature Levels

    OpenAIRE

    Bertsch, Stefan; Uhlmann, Michael; Heldstab, Andres

    2014-01-01

    Aim of the project is the development of a new heat pump system with economizing that is able to improve the heating performance using two or more different heat sources. These heat sources preferably on different temperature levels are incorporated in the system with minimal loss of exergy, by adding the heat at different pressure levels. Applications are i.e. buildings with heat pump and a solar thermal collector. While solar thermal systems can be used for heating and domestic hot water in...

  20. Role of radiogenic heat generation in surface heat flow formation

    Science.gov (United States)

    Khutorskoi, M. D.; Polyak, B. G.

    2016-03-01

    Heat generation due to decay of long-lived radioactive isotopes is considered in the Earth's crust of the Archean-Proterozoic and Paleozoic provinces of Eurasia and North America. The heat flow that forms in the mantle is calculated as the difference between the heat flow observed at the boundary of the solid Earth and radiogenic heat flow produced in the crust. The heat regime in regions with anomalously high radiogenic heat generation is discussed. The relationship between various heat flow components in the Precambrian and Phanerozoic provinces has been comparatively analyzed, and the role of erosion of the surfaceheat- generating layer has been estimated.