New prospects in the political economy of inner-Caspian hydrocarbons and western energy corridor through Turkey

This paper makes a new conceptualization on Caspian energy system and the transit routes that pass through Turkey. Firstly, it puts forward the term of “inner-Caspian”, comprising Azerbaijan, Kazakhstan and Turkmenistan. Secondly, it identifies sub-systems of “western energy corridor through Turkey” (WECT) by diversifying: (1) “WECT inner-Caspian”, which includes hydrocarbon transportation from Azerbaijan, Kazakhstan and Turkmenistan; (2) “WECT Russia”, which is currently composed of Blue Stream gas pipeline and oil transportation by tankers through Turkish straits; and (3) “WECT Middle East”, which refers to Iranian, Iraqi and Egyptian hydrocarbons. Thirdly, this paper makes a comparative analysis on WECT systems through selected economic (reserves, supply/demand, production and transportation costs), geo-political (e.g. moves of the concerned actors), political (e.g. recent developments in government structures) and security (especially in terms of transport) indicators which bring out that “it is more reasonable for the EU to first embrace WECT inner-Caspian, then develop WECT Middle-East in order to diversify its energy supply”.     

A probability density function for daily insolation within the temperate storm belts

Long-term insolation data are frequently obtainable either from recordings or from various empirical formulae. Many radiation-driven processes are, however, highly non-linear. The ability to model the correct long-term frequency distribution of a sequence of radiation events having a specified long-term mean insolation, is, therefore, valuable. This paper emphasizes that the “U-shaped” cloud cover frequency distribution, characteristic of the temperate storm belts, is “mapped” into the irradiation domain in a way that augments the number of “poor” and “excellent” days of sunshine at the expense of “average” days. An analytical and adjustable model is proposed, correlating the probability density of daily clearness index with the monthly average clearness index. This model is tuned to the two longest records of solar radiation in Norway, and it is verified against independent observations from the northern temperate storm belt.     

Nuclear methane reforming for coal gasification

The G.E.G.N. (Groupement pour l'Etude de la Gazéification Nucléaire) is a group which will study nuclear coal gasification and which is formed by “Commissariat à l'Energie Atomique”, “Gaz de France”, “Charbonnages de France”, “Creusot-Loire” and “Novatome”. The G.E.G.N. was created in 1976, with the approval of the French government, to determine a coal gasification process, to define a R & D programme and to evaluate the cost of the process.

The nuclear steam reforming of methane and the hydrogasification of coal were chosen as preliminary options. The hydrogasification was also chosen because the temperatue level of the steam reforming is lower than that of the coal steam gasification.

Therefore, it seems reasonable to limit the core outlet temperature to 850°C, although the core can deliver higher helium temperatures.

The use of an intermediate circuit allows a great flexibility in the reformer design and makes it easier to handle the catalyst.

In this paper the reasons for these choices are explained and the technological solutions are discussed.     

Residential hot water use patterns in Greece

This paper presents the results from the monitoring of hot water consumption in four apartment buildings that are located in Solar Village 3, in Greece. The buildings were monitored centrally for hot water consumption using a Data Acquisition System (DAS). The hot water is prepared in one building by an air-to-water heat pump and in the other three buildings by central solar plants. The main objective of the paper is the development of average residential hot water use patterns based on data from actual measurements conducted over the period September 1990 to August 1991. Average hourly, daily, and yearly profiles, which refer to central DHW systems, are presented and discussed. The average hot water consumption “per person” is also concluded. In addition, the effect of “family size” in hot water use is examined. It was found that the majority of the families consume between 25 and 35 liters per person per day, and the mean annual energy consumption is 0.83 kWh per person per day.     

Architecture and performance of neural networks for efficient A/C control in buildings

The feasibility of using neural networks (NNs) for optimizing air conditioning (AC) setback scheduling in public buildings was investigated. The main focus is on optimizing the network architecture in order to achieve best performance.

To save energy, the temperature inside public buildings is allowed to rise after business hours by setting back the thermostat. The objective is to predict the time of the end of thermostat setback (EoS) such that the design temperature inside the building is restored in time for the start of business hours.

State of the art building simulation software, ESP-r, was used to generate a database that covered the years 1995–1999. The software was used to calculate the EoS for two office buildings using the climate records in Kuwait. The EoS data for 1995 and 1996 were used for training and testing the NNs. The robustness of the trained NN was tested by applying them to a “production” data set (1997–1999), which the networks have never “seen” before.

For each of the six different NN architectures evaluated, parametric studies were performed to determine the network parameters that best predict the EoS. External hourly temperature readings were used as network inputs, and the thermostat end of setback (EoS) is the output. The NN predictions were improved by developing a neural control scheme (NC). This scheme is based on using the temperature readings as they become available. For each NN architecture considered, six NNs were designed and trained for this purpose. The performance of the NN analysis was evaluated using a statistical indicator (the coefficient of multiple determination) and by statistical analysis of the error patterns, including ANOVA (analysis of variance).

The results show that the NC, when used with a properly designed NN, is a powerful instrument for optimizing AC setback scheduling based only on external temperature records.     

The calculation of wall and fluid temperatures for the incompressible turbulent boundary layer, with arbitrary distribution of wall heat flux

Numerical solution of the partial differential equation for heat transfer in the incompressible turbulent boundary layer has been obtained for uniform (q_w/ρC_pu_i)/√(c_f/2) and for Prandtl numbers 0–7, 1 and 7. The Spalding boundary-layer velocity law was assumed, and the Schmidt method of integration used. Boundary-layer temperature distributions up to x⁺ = 10⁶ are presented, together with the “Spalding function” St/√(c_f/2). A method is given for the application of the solutions to the case of arbitrary distribution of heat flux at the wall.     

Heat transfer in simulated boiling

An experimental study was undertaken to determine the variations of heat-transfer coefficient on a submerged heating surface while air bubbles were injected into the liquid through an orifice in the plate. The results indicated that heat transfer is most intensive during the time that the bubble detaches from the surface. This casts doubts on boiling heat-transfer correlations based on bubble growth or rising phase considerations. In conclusion, it is suggested that the “agitation” and “latent heat” views of boiling heat transfer may be combined in a unified model.     

Optimization of an absorber plate fin having a step-change in local thickness

Solar collectors having “tube-and-fin” absorber plates have traditionally used rectangular fins. The introduction of a “step-change” in fin thickness, so that the fin is thinner far from the tube, permits a savings in material content. Through heat transfer analysis, this paper derives an expression for the efficiency of a fin of this step-change shape, and applies it to the problem of finding the savings in material this shape permits. The results indicate that roughly a 20% reduction in fin material is possible.     

On the efficiency of night ventilation techniques for thermostatically controlled buildings

A new, integrated method to calculate the energy contribution of night ventilation techniques to the cooling load of a building is presented in this paper. The method is based on the principle of “Balance Point Temperature” and permits the calculation of the energy required to cool a building to acceptable comfort conditions when night ventilation techniques are used. It also permits the calculation of the energy contribution of night ventilated buildings compared to conventional air conditioned buildings. The proposed method is successfully validated with data from an extended and detailed simulation procedure using the TRNSYS simulation programme to calculate dynamically the thermal performance of buildings using night ventilation techniques. It is found that the method is of sufficient accuracy and can be used during the predesign as well as the design phase of a building to access the performance of night ventilated buildings.     

Heat transfer through the turbulent incompressible boundary layer in the presence of moderate pressure gradient

From the assumption that the “universal law of the wall” is applicable to the turbulent boundary layer for moderately accelerating and decelerating flows along a wall it is shown that the thickness and the eddy diffusivity variation through the thickness can be derived at any Reynolds number.

With the additional assumption that the eddy diffusivities for momentum and heat are equal solutions were carried out to the energy equation to obtain Stanton number variations with Reynolds number for both uniform wall temperature and uniform wall heat flux. Two Reynolds number values were considered at which the heating commenced, Prandtl numbers of 0.01, 0.7 and 10 were used and these cases were examined for a number of arbitrarily chosen uniform pressure gradient parameters corresponding to one dimensional diverging or converging ducts.     

Myths in passive solar design

For years passive solar design principles have been perpetuated without being reexamined or questioned regarding their relevance in the context of new materials and constructions. Rarely does an architect get quantitative feedback on system or concept performance after the building is built. The result has been the perpetuation of beliefs among conference papers, text books and popular articles, all too often based only on belief. In this paper examples of premises which likely deserve to be kept passive rather than acted on are challenged. Designers are encouraged to ask three questions when applying a commonly held rule or assumption: Does it address the right issue? Does it apply, given the properties of new components and materials? If the premise is violated, how badly is comfort or the energy balance affected? Examples taken from monitoring and sensitivity studies illustrate the importance of asking “stupid” questions.     

A new analytical expression for the drag of a flat plate valid for both the turbulent and laminar regimes

An analytical expression for the “law of the wall”, valid for the laminar, turbulent and intermediate regions, is shown to permit the derivation of explicit relations connecting: the local drag coefficient and the momentum-thickness Reynolds Number; the local drag coefficient and the length Reynolds Number; and the overall drag coefficient and the length Reynolds Number. Agreement is good with the Prandtl-Schlichting formula at high Reynolds Numbers and the Blasius solution at low Reynolds numbers. An extension to flows with stream-wise pressure gradients is presented.     

Prospect of RBMK-NPPS strength monitoring system on-line module development

System for strength monitoring and residual lifetime (SMS) assessment of NPP equipment makes it possible to improve safety and effectiveness of operation.

According to SMS concept it includes two main modules: for on-line data acquisition and diagnostic and for off-line date processing and lifetime assessment.

Algorithm for RBMK SMS on-line module is proposed to be based on the basis of “DASHA” expert system shell.

Universal expert shell “DASHA” was created using the original matrix method of image identification theory and can be used for on-line diagnostic system development for any complex technological object of arbitrary physical nature.     

Some environmental and safety aspects of using hydrogen as a fuel

At present, less than 7% of the hydrogen produced in the U.S. is delivered to users as “merchant” hydrogen. The balance is produced and used as “captive” hydrogen as a chemical intermediate. In the future it is probably that this pattern will change and that the predominant use for hydrogen will be as fuel. In this paper the discussion of environmental and safety considerations related to the use of hydrogen is focused primarily on its use as a fuel for autos, trucks and buses, and for aircraft. The objective is to bring some of the interesting generalities of the subject to the attention to those who are just acquiring an interest in the potential of hydrogen, as well as for those specialists in hydrogen technology who may not have given much thought to these considerations.     

Thermodynamics applied to oxygen enrichment of combustion air

In order to reduce overall fuel consumption, or to partially substitute a “valuable” fuel with a poor one, in industrial heating, oxygen enrichment of combustion air can be very effective. For the second option, a general criterion is stated in this paper for examining the suitability of oxygen enrichment in single cases. The topic is particularly interesting, as for the first time, it is now feasible to produce oxygen enriched air using permeable membranes on a commercial scale and with costs that are remarkably lower than those of other existing techniques. In this paper, the subject is investigated after some remarks about the definition of the “usable exergy” parameter, which was already proposed in previous papers by one of the authors and is here utilized for the above criterion.     

Energy from Waste: A Wholly Acceptable Waste-management Solution

This paper briefly reviews the “waste management hierarchy” and why it should be treated as a checklist and not a piece of unquestioning dogma. The role of energy from waste (EfW) is examined in depth to show that it is a rigorous and environmentally sound waste-management option which complements other components of the waste-management hierarchy and assists resource conservation.     

Strain gradient-induced diffusion of hydrogen in palladium and nickel membranes

The “uphill” diffusion of hydrogen during permeation through flat sheets of palladium and nickel has been studied by an electrochemical permeation method at 303 K. For both annealed and “as cold rolled” Pd samples, uphill diffusion effects on hydrogen absorption and desorption have been observed over a range of initial hydrogen contents from about H/Pd = 0.01, i.e. near or slightly less than the _max composition, up to H/Pd = 0.25–0.3. The occurrence of a non-Fickian component of permeation flux has been associated with temporary formation of lattice volume differences across the ( + β)/β and ( + β)/ interfaces during absorptions and desorptions, respectively. Influences of the magnitudes of galvanostatic hydrogen fluxes and of the membrane thickness on the uphill effects were examined. Analogous uphill effects were observed in similar studies with nickel membranes also in both annealed and “as cold rolled” states, which were much larger than those observed for palladium.     

Global oil outlook: return to the absence of surplus and its implications

As we approach the end of the 20th century, the global oil picture starts to look more like the early 1970s, which set the scene for the first oil crisis in 1973. The “security margin” — the gap between demand and production capacity, has been shrinking since the early 1990s. In 1985 OPEC was producing at only 55% of capacity. By 1997 capacity utilization had risen to 95% and, barring the full re-entry of Iraq into the oil market, capacity utilization in 1998 is projected to rise to 96% with a growth of more than 1.6 million barrels a day (mbd) in global demand. No wonder, then, that the “capacity question” has been termed “oil's perennial problem”. The dilemma confronting producers is either they face the danger of over investing if demand grows slowly or not at all, or they run the risk of investing too little, too late. Yet, without outright investment, the capacity constraint may start to bite at some point in the near future. This paper will endeavour to analyse the origins of the shrinking “security margin” and its impact on the global oil supplies, the price of oil and the global economy. It will argue that under such conditions, one has to seriously consider the possiblity of a third oil crisis capable of again disrupting the global economy, triggered again by political upheaval in the Middle East.     

Thermal performance of air-heating solar collectors with thick, poorly conducting absorber plates

Expressions are derived for the efficiency and loss factors of a coverless, air-heating solar collector in which it is possible to assign finite values for the thickness and thermal conductivity of the absorber plate. In the geometry treated, air flow is beneath a flat absorber, and heat transfer is both steady state and one dimensional. The expressions are validated by outdoor measurements from a fullscale tile roof used as a collector and by indoor measurements from tile and metal roof sections tested in a heating simulator. For the tile roofs, the expressions presented give better agreement with experiment than do expressions based on the usual “thin plate” models since the absorber is thick and poorly conducting. Efficiency characteristics of the full-scale tile roof are also presented. Trapezoidally profiled metal panels are commonly used as a cladding for industrial buildings; it is shown that their performance as collectors may be described by a “fin and tube” model. Information is presented in a format that is useful for design and may be used in computer models of the thermal performance of solar-assisted buildings comprising these, or similar, collection devices.     

Assessment of thermal stresses and ratchetting in reactor vessels

Reactor vessels are often subject to “hot spots” developing at certain positions on the shell, which, if they are of a cyclic nature, may result in strain growth and fatigue failure if the amplitude of the cyclic strains are not restricted.

The paper deals with an investigation of a particular vessel with the object of determining the characteristics of “hot spots” that would cause cyclic plasticity or ratchetting in order to determine the limiting criteria to avoid or restrict such effects onder continuous operational conditions.

The basis of the investigation is finite element analysis. Temperature dependent elasto-plastic material properties are taken into account and the mesh is refined in selected “hot spot” positions in order to obtain accurate strain and stress states under cyclic loading conditions.

The assessment criteria are discussed which are the basis of recommendations for continuous operation under cyclic conditions.