江苏高邮地埋管热响应试验及浅层地热能资源评价

为研究江苏高邮浅层地热能资源储量,选取2个典型区块开展现场热响应试验,以线热源理论为建模基础,结合地埋管进出水温度试验数据,建立了典型区块内地埋管热传导模型,采用体积法对研究区浅层地热能资源作出定量评价。数据分析表明:在G001孔处,初始地层温度为17.69℃,导热系数为1.389 W/(m·K),钻孔内传热热阻为0.111 K/W,热扩散系数为0.921×10^(-6) m^(2)/s,热容量为1.508×10^(6) J/K,单位延米换热量为104.98 W/m;在G002孔处,初始地层温度为18.58℃,导热系数为2.340 W/(m·K),钻孔内传热热阻为0.110 K/W,热扩散系数为0.229×10^(-6) m^(2)/s,热容量为10.200×10^(6) J/K,单位延米换热量为163.34 W/m。综上试验参数计算结果可知,区内每年可开发浅层地热能储量至少为6.47×10^(13) kJ。试验设计合理,所得参数真实可靠,可为高邮浅层地埋管地源热泵工程后续设计工作提供基础数据与技术支撑。

南通市主城区浅层地热能热物性参数测试及资源量评价

岩土体热物理参数及地热资源量对于浅层地热能开发具有重要意义。为获取南通市主城区热物理参数及浅层地热能资源储量,在研究区内开展了10组现场热响应试验。以线热源理论为建模基础,结合相应地层数据和试验参数,概化出研究区地埋管热传导模型,采用体积法对南通市主城区浅层地热能资源作出定量评价。结果表明:研究区初始地层温度在18.36~20.16℃。在钻孔埋管深度范围内,岩土体的导热系数在1.35~1.88W/m·K,钻孔内传热热阻为0.123~0.125(m·K)/W,热扩散系数为(0.3208~3.3089)×10^(-6)m^(2)/s,热容量为(0.42~4.36)×10^(6)J/(m^(3)·K),单位延米换热量为30.88~69.33W/m。综上试验所得参数计算可知:区内每年可开发浅层地热能储量至少为2.20×10^(14)kJ。试验成果可为后续南通市主城区浅层地埋管地源热泵工程设计提供有力的数据与技术支撑。

如皋城北街道现场热响应试验及浅层地热能资源评价

为获取研究区内热物理参数及浅层地热能资源储量,文章开展了3组现场热响应试验,以线热源理论为基础,结合相应地层数据和试验参数,建立地埋管热传导模型,利用体积法定量评价如皋城北街道浅层地热能资源量。研究表明,如皋城北街道100m范围内浅层地热能热容量为4.88×1013kJ/K。通过合理利用与开发浅层地热能,每年可节省约832.4万吨标准煤。该研究成果可为本区域内浅层地热能的科学规划及绿化开发利用提供技术支撑。

地源热泵地埋管换热器热响应测试分析

为了获得花岗岩地区岩土热物性参数,以指导地埋管地源热泵系统的设计。以青岛市某小学地源热泵测试工程为例,通过开展岩土原位热响应测试工作,得到花岗岩场区岩土平均初始温度、岩土体平均导热系数、每延米地埋管换热器换热功率等岩土热物性参数,并进一步计算了工程场区浅层地热能可采资源储量,对场区浅层地热能进行了评价。结果显示,拟建花岗岩场区岩土初始平均温度为15.72℃,岩土体综合平均导热系数为2.67 W/mK;拟建场区浅层地热能可开采资源量夏季工况为1 635 kW,冬季工况为1 070 kW,可为23 357 m^2建筑提供夏季制冷和11 888 m^2建筑提供冬季供暖。表明拟建花岗岩场区岩土体导热能力较好,测试和分析方法可为相似工程提供借鉴。

GEOTHERMAL RESOURCES ASSESSMENT AND NUMERICAL SIMULATION IN TUANBO REGION

This paper mainly deals with the reservoir on the heat and mass transfer and mass and energy balance in a geothermal field.On the basis of briefing the general characteristics of the reservoir and the supposition of the reservoir modeling,the paper emphasizes the mathematical descriptions of hydra thermal transportation and convection by two methods according to the different models,such as lumped parameter model and distributed parameter model.It is effective to use these models in simulating the heterogeneous,and anisotropical fracture reservoir for the designed lifetime of 15 years.

Experimental assessment of two-phase bubble pump for solar water heating

The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.

Measuring Thermal Mass of Sustainable Concrete Mixes

Thermal mass is currently evaluated with ＂admittance＂ which is the ability of the element to exchange heat with the environment and is based on specific heat capacity, thermal conductivity and density. The aim of this study is to evaluate the effect of thermal properties namely, density, specific heat capacity and thermal conductivity on thermal mass. The objective of the study is to carry out laboratory experiments by measuring such thermal properties of concrete mixes with various percentages of GGBS （ground granulated blast furnace slag）, PFA （pulverized fuel ash）, and SF （silica fume） and RCA （recycled coarse aggregates）. The results obtained from these tests would contribute to the evaluation of how such thermal properties influence the thermal admittance and hence the thermal mass performance of sustainable concrete elements in a building system.

Preparation of MnO_2 and calcium silicate hydrate from electrolytic manganese residue and evaluation of adsorption properties

Electrolytic manganese residue(EMR), a high volume byproduct resulting from the electrolytic manganese industry, was used as a cheap and abundant chemical source for preparing MnO2 and EMR-made calcium silicate hydrate(EMR-CSH). The MnO2 is successfully synthesized from the metal cations extracted from EMR, which can effectively recycle the manganese in the EMR. By the combination of XRD, SEM and EDX analysis, the as-prepared MnO2 is found to exhibit a single-phase with the purity of 90.3%. Furthermore, EMR-CSH is synthesized from EMR via hydrothermal method. Based on the detailed analyses using XRD, FT-IR, FE-SEM, EDX and BET surface area measurement, the product synthesized under the optimum conditions(p H 12.0 and 100 °C) is identified to be a calcium silicate hydrate with a specific surface area of 205 m2/g incorporating the slag-derived metals(Al and Mg) in its structure. The as-synthesized material shows good adsorption properties for removal of Mn2+ and phosphate ions diluted in water, making it a promising candidate for efficient bulk wastewater treatment. This conversion process, which enables us to fabricate two different kinds of valuable materials from EMR at low cost and through convenient preparation steps, is surely beneficial from the viewpoint of the chemical and economical use of EMR.

New Li-ion Battery Evaluation Research Based on Thermal Property and Heat Generation Behavior of Battery

We do a new Li-ion battery evaluation research on the effects of cell resistance and polariza- tion on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 cells with different capacities and electrode materials are evalu- ated by measuring input and output energy which change with charge-discharge time and current. Based on the results of these tests, we build a model of energy loss in cells＇ charge- discharge process, which include Joule heat and polarization heat impact factors. It was reported that Joule heat was caused by cell resistance, which included De-resistance and reaction resistance, and reaction resistance could not be easily obtained through routine test method. Using this new method, we can get the total resistance R and the polarization parameter U. The relationship between R, η, and temperature is also investigated in order to build a general model for series of different Li-ion batteries, and the research can be used in the performance evaluation, state of charge prediction and the measuring of consistency of the batteries.

Evaluation of Nuclear Fuel Centerline Temperature Using New UO2 Thermal Conductivity Models

The nuclear industry needs of prediction of behavior and life-time, for a wide range of normal, off-normal and accident conditions for safe and economic operation. Among different thermo-mechanical properties that can be predictable, the knowledge on the radial temperature distribution of the UO2 （uranium dioxide） nuclear fuel during the operation of nuclear reactors is essential for safety as different mechanical and thermal-hydraulic thresholds should be respected. One of the attributes of the Brazilian CNEN （Nuclear Energy Commission） is to assess the performance of the fuel rods used in these reactors in high-bumup regimes. The effective removal of the heat generated in the fuel rods constitutes one of the primary points to consider in the design of nuclear reactors. One of the important physical parameters in the study of heat conduction from the nuclear fuel to the coolant in a PWR （pressurized water reactor） is its thermal conductivity. It is therefore desirable that the empirical models, updated for the calculation of thermal conductivity in the fuel region be developed from new sets of experimental data from the irradiated fuel rods in controlled environments This paper presents the obtained results of implementing of a new model for thermal conductivity of the UO2 in the FRAPCON code.

Performance Evaluation of New Two Axes Tracking PV-Thermal Concentrator

The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.

Fabrication and performance evaluation of the thermoelectric generation and performance measuring system

A novel thennoelectric generating and performance measuring system （TGPMS） was designed and fabricated. TGPMS can not only achieve the function of thennoelectric generation, but also measure the thennoelectric performance parameters of the bismuth-telluride-based thennoelectric device accurately. These thennoelectric performance parameters mainly include the dependence of the Seebeck coefficient of the thennoelectric device on the device＇s temperature in the low temperature range （about 40 ~ 190~C ）, and the dependence of the power output and thermoelectric conversion efficiency on the temperature dif- ference or output load. With the optimum load, the optimal value of the power output is 3.39W when the temperature difference reaches 231.2~C, and the optimal value of the conversion efficiency is 3.22% when the temperature difference reaches 208.9~C. TGPMS provides an experimental foundation for the application of the thennoelectric generators in the space field.

Experimental Evaluation of Thermal Properties of Grouting Materials

This study is aimed at the thermal analysis of sealant mortar （usually a mixtures of bentonite and cemem with addition of sand） used in geothermal cooling and heating. In particular, thermal conductivity and diffusivity measurements were performed on differem sealant mixtures by using Hot Disk thermal constants analyzer in order to identify the interesting thermal properties of grouting materials. The grouting materials that we considered are of porous nature and, if used in the presence of groundwater, have different levels of imbibitions. It is important to know the thermal behavior of these materials at different water content. A first set of measurements was performed on a not-tinted material at room temperature; then the samples were led to saturation conditions by contact capillary imbibitions with a cotton wool layer moistened in water. The determination of thermal conductivity in these test conditions appears to be critical compared to the measuremems on non-timed sample. The thermal conductivity tests have revealed how the thermal behavior of the samples analyzed is essentially determined by the density and water content of the material： in fact, the thermal conductivity increases of two to three times the value of the not-tinted material.

An Evaluation of R134a and R245fa as the Working Fluid in an Organic Rankine Cycle Energized from a Low Temperature Geothermal Energy Source

The characteristics of an organic Rankin cycle designed to operate with a low temperature geothermal source and constant temperature cooling water supplied from freshwater ponds typical to those found near Waddan City in the Al Jufrah region of Libya were examined. Two working fluids were examined and it was concluded that the most suitable for this application was R-245fa. The off design performance of the organic Rankine cycle was examined and it was shown that the cycle is controlled by the performance of the condenser which is cooling water side temperature limited.

Development of Performance Evaluation Technique for Shell-Tube Heat Exchangers

As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currently, thermal performance management of heat exchangers is more importantly issued for long term operation. Therefore, the performance evaluation techniques are required to improve the present method for the integrity evaluation of heat exchangers because of the exclusion of fouling calculation and the uncertainty analysis. This paper describes the developed thermal performance evaluation technique applied to the safety-related heat exchangers such as component cooling heat exchangers in a nuclear power plants.

Evaluation of the Thermodynamic Performance of the Traditional Passive Systems

The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.

Analysis of Forging Dies Coated with Tungsten Carbide through HVOF Processing

In this paper we present a performance evaluation of thermal spraying coated hot forging dies conducted in a production line. The High Velocity Oxy-Fuel process was used for the deposition of a tungsten carbide coating, which is characterized by its optimal adherence and low porosity. A metallurgical characterization of the layer was previously done, in order to obtain reference information to assist in the interpretation of the practical tests results. The coated die allowed an increase in productivity of 37.5%, besides better dimensional stability results through the process and legibility of printed numbers.

Exergy-Economic Criteria for Evaluating Heat Exchanger Performance

Based on the exergy-economic analysis of heat exchanger heat transfer and flow process, two new exergy- economic criteria which are defined as the total costs per unit heat transfer rate ηt for heat transfer exchanger and the net profit per unit heat recovery rate ηr for heat recovery exchanger respectively are put forward. Furthermore , the application of criteria is illustrated by the evaluation of down-flow, counter-flow and cross-flow heat exchangers performance. The methods employed and results presented in this paper can serve as a guide for the performance evaluation of heat exchangers.

Heat transfer performance evaluation of one-stream heat exchangers and one-stream heat exchanger networks

One-stream heat exchangers and one-stream heat exchanger networks are widely used in engineering. In this paper, the heat transfer performance evaluation of one-stream heat exchangers and one-stream heat exchanger networks is analyzed with the concepts of entropy generation rate, entropy generation number, revised entropy generation number, entropy resistance, entransy dissipation rate, entransy dissipation number and generalized thermal resistance. For the analyzed one-stream heat exchangers, our numerical results show that the extremum value of the entransy dissipation rate and the minimum values of the entropy resistance and the generalized thermal resistance always lead to the largest heat transfer rate or the lowest temperature of the cooled object,while the minimum values of the other parameters do not always. For the analyzed one-stream heat exchanger networks, the minimizations of entransy dissipation rate, entransy dissipation number and generalized thermal resistance always correspond to the lowest average temperature of the cooled objects, while the minimizations of the other parameters do not. Therefore, only the extremum entransy dissipation principle and the minimum generalized thermal resistance principle are always applicable for the heat transfer performance evaluation of the systems in this paper, while the applicability of the other parameters is conditional.