In certain extremely low probability, severe accident scenarios which have been postulated for liquid metal cooled fast reactors, large bubble cavities containing fuel vapor and fission products transit a layer of coolant and release this material to the cover gas thereby presenting a contribution to an accident-specific source term [5]. Rayleigh model in radiation heat transfer has been investigated to analysis and interpret the experiments that conducted during 1980's for oxide UO 2 fueled reactors in Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL).These analyses are applied to estimate the bubble collapse of Liquid Metal reactors (LMR's) during a hypothetical core disruptive accident (HCDA). In Rayleigh non-scattering model the particle size was 0.01 µm [6],and according to Mie theory principle, the absorption coefficient for small particle-size distribution was estimated (k = 10 m-1 was used) from reference [7] at complex refractive index of UO 2 at λ = 600 µm and x = 0.0785.A MATLAB code was used to solvethe radiative heat equation (RTE) in spherical coordinates. The mixture is in local thermodynamic equilibrium inside the bubble which has a black body surface boundary.The mixture in the cavity contains three components: the non-condensable gas Xenon, Uranium dioxide vapor, and fog.To simulate fuel bubble's geometry as realistically as possible, according to experimental observation, the energy equation in a spherical coordinate system has been solved with the radiative flux heat transfer equation (RTE) to obtain the effect of fuel bubble's geometry on the transient radiative heat flux and to predict the transient temperature distribution in the participating medium during a hypothetical core disruptive accident (HCDA) for liquid metal fast breeding reactor (LMFBR) for FAST. The transient temperature distribution in fog region was utilized to predict the amount of condensable UO 2 vapor = − ! " ! #. The conclusion that can be drawn from the present study, is that the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory has a larger margin of safety since the bubble rising time is greater than the bubble collapse time.

In certain extremely low probability, severe accident scenarios which have been postulated for liquid metal cooled fast reactors,large bubble cavities containing fuel vapor and fission products transit a layer of coolant and release this material to the cover gas thereby presenting a contribution to an accident-specific source term [5].Mie model in radiation heat transfer has been investigated to analysis and interpret the experiments that conducted during 1980's for oxide UO 2 fueled reactors in Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL).These analyses are applied to estimate the bubble collapse of Liquid Metal reactors (LMR's) during a hypothetical core disruptive accident (HCDA).InMie scattering model the particle size was 0.07 µm [6]. The scattering coefficient of UO 2 particles (σ = 1.24 m-1), was calculated by using Mie theory,at the same number of stable nuclei's N (2.9 E15 nuclei/m 3) that resulted from theabsorbed coefficientk = 0.082 m-1 [7].P 1 approximation method was used to solve the radiative heat transfer equation (RTE) in spherical coordinates of participating medium confined between the two concentric spheres.The surfaces of the spheres are assumed to be gray, diffusely emitting and diffusely reflecting boundaries, and an isothermal boundary conditions were assumed at these surfaces.Marsak's boundary condition was to computed, the net radiative heat flux q(τ), and the incident radiation G(τ), to analyze and interpret the CVD experiments data that were conducted in the FAST facility at ORNL [8] and Fast Flux Test Facility reactor (FFTF) in Argonne National Laboratory ANL.The conclude that extracted from this study is greater margin of safety when the bubble rising time is greater than the bubble collapse time since the bubble collapses (UO 2 condenses) before it can reach the top of the vessel therefore there is less chance of release of aerosol as in Oak Ridge National Laboratory (ORNL) FAST experiments and Argonne National Laboratory (FFTF) reactor.

Abstract: A conventional ground-coupled heat pump (GCHP) can be used to supplement heat

rejection or extraction, creating a hybrid system that is cost-eective for certainly unbalanced climes.

This research explores the possibility for a hybrid GCHP to use excess heat from a combined heat

power (CHP) unit of natural gas in a heating-dominated environment for smart cities. A design for

a multi-family residential building is considered, with a CHP sized to meet the average electrical

load of the building. The constant electric output of the CHP is used directly, stored for later use in a

battery, or sold back to the grid. Part of the thermal output provides the building with hot water,

and the rest is channeled into the GCHP borehole array to support the building’s large heating needs.

Consumption and weather data are used to predict hourly loads over a year for a specific multi-family

residence. Simulations of the energies exchanged between system components are performed, and a

cost model is minimized over CHP size, battery storage capacity, number of boreholes, and depth of

the borehole. Results indicate a greater cost advantage for the design in a severely heated (Canada)

climate than in a moderately imbalanced (Ohio) climate.

The multi-family residential building sector is the least energy efficient in the United States, thus allowing for ample opportunities for significant cost-effective energy and carbon savings. In the present study, we propose a district solar borehole thermal solar energy storage (BTES) system for both retrofit and new construction for a multi-family residence in the Midwestern United States, where the climate is moderately cold with very warm summers. Actual apartment interval power and water demand data was mined and used to estimate unit level hourly space and water heating demands, which was subsequently used to design a cost-optimal BTES system. Using a dynamic simulation model to predict the system performance over a 25-year period, a parametric study was conducted that varied the sizes of the BTES system and the solar collector array. A life-cycle cost analysis concluded that is it possible for an optimally-sized system to achieve an internal rate of return (IRR) of 11%, while reducing apartment-wide energy and carbon consumption by 46%. Both a stand-alone and solar-assisted ground-source heat pump system were designed and simulated for comparison to the BTES system, and found to be less economically favorable than the solar BTES system. Thus, the promise for district-scale adoption of BTES in multi-family residences is established, particularly for new buildings.

A novel geothermal heat pump (GHP) system with an integrated low- to moderate-temperature salt hydrate phase change material (PCM) storage tank for buildings in cold climates is proposed in this study. The purpose of the PCM storage tank is to dampen peak heating loads and to remove annual ground thermal load imbalances on the ground heat exchanger (GHX) to assist in achieving an optimally-sized GHX. As heat is extracted from the closed-loop system by heat pumps in heating mode, a significant portion of this heat is used to solidify a salt hydrate PCM. This heat of fusion is later released back into the heat transfer fluid, storing it in the PCM tank and GHX for later diurnal and seasonal use. To examine the merits of the proposed concept, electric utility meter data on 15-minute time intervals were mined from an actual apartment building and used to estimate space heating, cooling, and hot water heating loads. Those data were used in an hourly, dynamic 20-year life-cycle simulation model in TRNSYS to design an optimum combination of GHX and PCM storage, where each component was sized to balance the annual ground thermal loads. The system simulation results show significant potential for GHX size reduction with a PCM storage tank, but the system is quite sensitive to the PCM melt temperature due to significant hysteretic nature of the salt hydrate PCM heating and cooling curves. We also find that there is no unique optimum unless other factors are considered such as installation cost and physical constraints; many combinations of GHX size and PCM mass are capable of achieving the design goal with similar annual electric energy consumption. For the cases examined here, a PCM melt temperature of 27 °C yields the most favorable economic results, and a preliminary economic analysis suggests that with typical drilling cost and PCM tank cost values, the GHX size can be reduced by over 50 %.

The metallurgical influence of niobium (Nb) on an annealed high manganese (Mn) steel is still an active issue of discussion between automobile companies and steel manufacturers. Some controversy exists in the literature concerning the influence of Nb solubility on microstructure and thereby on mechanical properties. The influence of Nb-solubility on microstructure of Fe30Mn alloy steel was investigated experimentally and by computational materials modeling. Nb was added in 0.05, 0.1, 0.2, 0.4, 0.6 and 1% additions and the alloy samples were annealed at 1200oC for 2, 5, 10, 30 and 60 minutes. The microstructure was investigated using an optical microscope, TEM and SEM-EDX and precipitates were chemically tested. Niobium solubility in Fe30Mn austenite was theoretically studied based on Gladman assumptions and was also examined by Thermo-Calc analysis. The result of this work is a comparison between the microstructure analysis and theoretical studies, and it has been found that Nb was soluble in Fe30Mn austenite phase and has had a solute drag effect where Nb(C,N) and NbN precipitates were seen and the effect was pinning effect 

Abstract— The optimized methods for a forecasting demand have been discussed among researchers to overview the most sufficient need in a rapid expansion city. The methods developed test and compare between all interrelated issues. Many variables are involved in the calculation of energy future demand, the prediction makes aggressive result to achieved requirements. After discussing proposed research methods a suitable and accurate approach is elected to be applied for any city to satisfy the public demand. The objectives of this research are to overview all the methods of forecasting of the electrical demand using different approaches , and come out with the most optimum suitable procedure in the field of electrical network for long and short terms. The result indicates a brilliant analysis with high contribution in the electrical industry, will find its application in a global rapid expansion city. The methods show a tradeoff between cost, reliability and complexity of operations regardless of energy generated.

With regard to oil production in Libya, the following instruments are particularly important:

- Sustainability guidelines

- Risk analyses

- Eco-efficiency analyses

- Balanced scorecards -

Key sustainability criteria (KPI)

- Certification systems

Sustainability consists of the balance between economic efficiency/economics on the one hand and ecology/environmental compatibility on the other. 15 Sustainable energy systems are always geared to demand. Energy is just one resource among many.

Employees, raw materials, knowledge, etc. are also important resources that need to be managed sustainably and a balance found. A system that is only one-sidedly focused on profit maximization or social compatibility